Whilst researching people, places and events surrounding the XJ13 I came across references to the West Yorkshire Foundry.

Who are they ... do I hear you ask? For the best part of 100 years the Foundry was responsible for the casting of cylinder heads and blocks for the British automotive industry. Have a look on practically any cylinder head or block made in the UK in the last 60 years and the chances are you will see the initials "WYF" cast into the block and/or head. For example, the following initials are proudly displayed on my prototype quad-cam engine block:

Prototype V12 casting marks.

The West Yorkshire Foundry emblem can be seen as an intertwined "W" and "Y". The other characters refer to the material of construction (LM8), Jaguar's experimental identification (XW 5014) and Part Number (C2020). If you look at more recent Jaguar blocks, the West Yorkshire Foundry initials are even more prominently displayed as shown on this SOHC V12 block from the 1980s:

SOHC V12 casting marks.

The West Yorkshire Foundry has had an association with Jaguar from the days of the SS Jaguars right up to the first years of the 21st Century - not only supplying castings for Jaguar's production cars but also one-offs and small runs for things such as the initial run of 10 castings for Jaguar's "XJ6" quad-cam V12 engine project (not to be confused with their later saloon of the same name). The supplied bare castings for the racing engine project were delivered to Coventry Climax in 1964 for final fettling before being delivered to Jaguar's Experimental and Competition Departments for assembly and installation.

Watch almost any programme or film on TV and you will see something that was made by the West Yorkshire Foundry - Aston Martin, Rolls-Royce, Jaguar, Rover and many more.

Having found almost nothing in print about the West Yorkshire Foundry I set about trying to learn a little more about them and their association with Jaguar. I had visions of perhaps stumbling across casting patterns and records of correspondence between the Foundry and Jaguar - perhaps even from the times of Jaguar's Le Mans successes in the 1950s through to the XJ13 project itself? These initial hopes were soon dashed when I discovered the Foundry had quietly closed in 2004 with almost no trace of its former existence to be found.

This is what is found if you visit parts of the site of the foundry today:

The West Yorkshire Foundry today.

Even more poignant if you superimpose a picture of a group of workers on a picture of some of the remaining original buildings:

What had happened to all those moulds, patterns, drawings and historic correspondence? It seemed that nothing had survived. I continued my search and , at the start of 2010, came across a website - www.fettling.com. The website reads,

The book, "Meltdown" and DVD referred to above are available from: 

Heads Together Productions, The Media Centre, 7 Northumberland Street, Huddersfield HD1 1RL E: adrian@headstogether.org

Leeds Industrial Museum, Armley Mills, Canal Road, Leeds, LS12 2UF T: 0113 263 7861 E: www.leeds.gov.uk

Waterstones, Albion Street, Leeds, LS1 6HX T: 0113 242 0839

The Round Foundry Media Centre, Foundry Street, Leeds, LS11 5QP T: 0870 420 2300 E: info@roundfoundry.net www.roundfoundry.net

"Meltdown - Words and Images from a Yorkshire Foundry"

The book and DVD do provide a fascinating glimpse into the day-to-day life and individuals who worked at the Foundry. Thankfully, someone had the foresight to preserve at least some images. The website also provides a forum connecting past employees and my research continues with surviving foundry-workers (bearing in mind the prototype engines were made almost 50 years ago!).

For now, here are some glimpses into the last days of the Foundry as shown in the DVD. I don't know how many copies of the book are left of whether there is enough interest to justify a reprint but I do recommend you add a copy to your personal library while you still can. It is currently on sale for a very reasonable £10.

Here are some excerpts from the book that accompanies the DVD:

"The Clarence Road Foundry was part of Leeds' manufacturing heritage for many years. Its closure brought to an end another chapter in our industrial history.

Engineering is concerned with the transformation of energy and the manufacture of industrial engines and power driven appliances. Defined in this way, Leeds was a pioneering city in the late eighteenth and nineteenth centuries. Millwrights were the earliest mechanical engineers, concerned with such 'prime movers' as water mills and waterwheels. By 1820, the steam power revolution was well underway in Leeds, thanks to its textile mill owners harnessing their operations to the ideas of inventors like Thomas Savery (1650-1715), Thomas Newcomen (1663-1729) and, more importantly, James Watt (1736-1819)...

... by 1938, the derelict foundries in Sayner Lane were occupied by the Airdale Light Alloy Company ... one source suggests that the Airdale Light Alloy Company had been given a small contract to manufacture aircraft parts, but could not meet the Ministry's tight deaadlines; as a result MAP asked Leyland Motors to step in and manage the foundry ... there was a distinct shortage of carburettors for the Rolls-Royce Merlin engines, which powered both the Spitfire and Hurricane fighter aircraft, during the Battle of Britain ... Leyland sent a small team of foundry specialists to Leeds ... in March of 1942,... the total weight of carburettors produced was less than that of other castings. He (Mr West of Leyland) was beginning to feel his task was completed ... by the end of the war it is probably true to say that many, if not all the carburettor bodies flying for the RAF had been made in Sayner Lane ...

The last tank produced at Sayner Lane by Leyland Motors - © British Commercial Vehicle Museum

... the resurrection of the wartime foundry in Sayner Lane, Leeds, as West Yorkshire Foundries in 1846 is closely linked with the development of the British Motor Industry in the second half of the twentieth century ... between 1948 and 1951, domestic sales accounted for less than 30% of the output of private cars and only 45% of commercial vehicles. The British Automotive Industry had become one of the world's key exporters of motor cars. It was into this favourable economic climate that the foundry at Sayer Lane emerged as a manufacturer of high quality iron and aluminium castings for cars and commercial vehicles ... rumour has it that, after the war, MAP sold the Sayner Lane Foundry to Leyland Motors for one pre-decimal penny as a gesture of gratitude for the Company's efforts during the war ... by 1961, production at West Yorkshire Foundries had reacged 120 tons of aluminium per week and 600 tons of grey iron ... the physical expansion of the plant was enormous, growing from 7,300 square yards in 1946 to 48,000 square yards in 1961 ... The Company, by 1961, employed 2,000 people to make 14,000 different parts for the domestic motor industry ... West Yorkshire Foundries supplied most of the motor manufactureres in Great Britain with cylinder blocks and heads ... Jaguar bought over thirty separate parts for their specialist car market and headed a list of customers which reads like a Hall of Fame for British car manufacturers ... in 1966 ... the West Yorkshire Foundries built a new state-of-the-art gravity die-casting foundry ... the main Aluminium Sand Foundry was producing the six cylinder heads for Jaguar and Rover ... Walter West retired from the company in 1969, and left behind a prosperous and expanding business ...

1954 advert

... however, sooner than West or anyone else could have anticipated, the cold blasts of merger, rationalisation and recession would be whistling at the foundry doors in Sayner Lane ... in Britain, output of vehicles per employee per year became an embarrassing statistic. The British needed 67% more labour to make a Ford Escort than the Germans, and 132% more than the Belgians to make a Mini ... as a result of a series of mergers and acquisitions, in 1962, Leyland Motors Limited became the British Leyland Motor Corporation; operating on sixty different UK sites - West Yorkshire Foundries being one of them ... British Leyland faced a serious cash-flow crisis and were forced to turn to the Government of the day ... Leyland were in a fight for their very survival ... under pressure from Margaret Thatcher's 'belt-tightening' Government, Michael Edwardes announced a long-overdue restructuring of British Leyland ... following an internal review of management and staff, the future of thirty Leyland sites was still in the balance; West Yorkshire Foundries was one of them ... in 1982, British Leyland was renamed the Austin-Rover Group and the foundry at Leeds continued to act in a limited way as a supplier of high-cored cylinder blocks and heads to the automotive industry ... (in) 1985/86, West Yorkshire Foundries was sold to a private German company (Eisenwerk Bruhl) ... Yorkshire Foundries changed its name to VAW Motorcast Ltd and flourished after 1997 ... in 2002, West Yorkshire Foundries once more faced the prospect of new owners (later to become Hydro Aluminium Motorcast Limited) ... within eighteen months ... Hydro decided there was too much capacity in the automotive cylinder head and block market and a worrying lack of orders beyond 2004 ..."

Announcement by Hydro Aluminium Motorcast

... by 2005, the foundry buildings in which they (the workforce) and generations before them had laboured, would be silent, empty and unused ..."

On Friday, 16th December 2011 a small group gathered around the XJ13 at Jaguar Heritage to mark the launch of Peter Wilson's book, "XJ13 - The definitive story of the Jaguar Le Mans car and the V12 engine that powered it".

This was no ordinary gathering, as those present included many surviving members of the team that were originally involved in the original XJ13 car as well as the development of the engine that powered it. Those present included Norman Dewis, George Buck, Frank Philpott, Jim Eastick, Ron Greves, Mike Kimberley, Roger Shelbourne, Robert Berry, Peter Taylor and Peter Wilson himself.

Click the images below to see videos and more detail of the proceedings

The videos include introductions by Tony Duckhouse (on behalf of Jaguar Heritage), Paul Skilleter (renowned Jaguar author and publisher) and further insights by Mike Kimberley (XJ13 Project Manager - later to join Colin Chapman and become CEO of Group Lotus):

More details of the book itself are available from Paul Skilleter Books or the Jaguar Clubs of North America.

A question often asked of me is,

"How many prototype V12 quad-cam engines were built by Jaguar and where are they now?"

As I reported on this blog back in May 2010, the answer is SIX. Of this six, only three progressed beyond test-bed stage and were installed in cars. A seventh engine was assembled as a 60° V8 and run on Jaguar's test bed. The V12 block for this engine was converted into a V8 using a special crankshaft with throws for only eight of the twelve cylinders. There were plans to assemble an eighth engine but it never reached the test bed stage.

The above has now been confirmed by XJ13-expert Peter Wilson in an excerpt from his forthcoming book which appears in the November 2011 issue of "Jaguar World". I can now add further confirmation of these facts from a collection of previously unknown and unpublished original documentation. These documents were in the personal collection of the late Claude Baily - the architect of Jaguar's quad-cam V12, their legendary XK engine and quad-cam 90° 8 litre V8 amongst others.

Jaguar's Claude Baily.

Claude Baily joined the SS Jaguar drawing office during the second World War and his engineering talents were soon exploited by Jaguar. Baily became intimately involved in Jaguar's plans to replace their pre-war engine designs with a new generation of engines designed to power their latest saloons. He is perhaps best known for his part in the design of the legendary XK twin-cam engine.

Claud Baily's appointment letter.
© Copyright Tony Bailey (WPO Communications) - not to be reproduced without permission.

Spending long war-time nights fire-watching in a small office above the assembly tracks in Coventry, in the company of William Lyons, William Heynes and Walter Hassan, the architecture of the world-beating XK engine was laid down. The new engine was required to reliably provide a minimum of 160bhp, have a long service life and be refined in operation. Before the end of the war, a number of experimental single-cylinder and full engines were evaluated. The following original document from 1941 is likely to relate to one such experimental engine. J.A.Prestwich was better known by its initials "J.A.P." whose engines were used in many famous motorcycle marques and early aeroplanes. Customers included Morgan, Triumph, Brough Superior, AJS and HRD.

12th December 1941 - letter to SS Cars referring to experimental engine.
© Copyright image - not to be reproduced without permission.

4, 6, 8 and 12 cylinder configurations were all considered at this very early stage but it was the 4 and 6 cylinder versions that were finally adopted. It has to be said that the BMW 328 engine played an important part in formulating the architecture of these engines. Indeed, Heynes was great friends with an owner of a 328, Leslie Johnson, who loaned his 328 to SS Cars for evaluation.  Johnson was a British racing driver who competed in rallies, hill climbs, sports car races and Grand Prix races. Johnson's car was highly developed and had raced pre-war. In my opinion, the styling of the XK120 owes much to the BMW. A BMW saloon was also acquired by SS during the war and was fitted with one of the early experimental engines (the "XG"). Walter Hassan used this car as his own personal transport for an extended period for evaluation. One of Jaguar's own 2.5 litre SS Saloons was also used for testing the prototype engines although most of the development work was carried out on the test bed.

3.5 litre experimental XK engine - drawing produced to calculate compression ration.
© Copyright image - not to be reproduced without permission.

Left to right - Walter Hassan, William Heynes, Claude Baily.
© Copyright image - not to be reproduced without permission.

Heynes and Baily applied all their thoughts on engine design to the XK engine although they later commissioned Henry "Harry" Weslake to help optimise their design. Jaguar already had a long association with Weslake, a cylinder head specialist who had been instrumental in modifying the side valve standard engine used in the first SS sports car. He also worked on the larger SS engine. It is believed he was involved in the design of every Jaguar engine up to and including the V12 of the early 1970s.

Harry Weslake - © Copyright image - not to be reproduced without permission.

The following Weslake report gives a fascinating insight into his evaluation methods and his closing summary bears testament to the soundness of the XK basic design. Weslake concludes:

".... The engine has stood up remarkably well through these series of tests. The valve gear has remained quiet throughout, there has been no sign of variation in oil pressure and the engine improves in power out-put the longer it runs. The tests have been very severe, particularly the distribution ones, but never once was any mechanical trouble experienced. It is suggested that some breather attachment should be developed in order to keep a small depression in the crankcase so that oil corrosion can be minimised and this would also help to stop oil leaks, particularly in the valve chest covers ..."

© Copyright image - not to be reproduced without permission.

© Copyright image - not to be reproduced without permission.

© Copyright image - not to be reproduced without permission.

© Copyright image - not to be reproduced without permission.

© Copyright image - not to be reproduced without permission.

© Copyright image - not to be reproduced without permission.

© Copyright image - not to be reproduced without permission.

The camshaft drive was by duplex roller chain - an arrangement that was carried forward to the quad-cam V12 prototype engines. This arrangement was used in the first engine installed in the XJ13 as well as the second engine built and tested in a Mk.10 Jaguar. The "genetics" of the XK engine could clearly be seen in the later quad-cam V12. The following page of sketches (made by Claude Baily around 1949/50) clearly show how he was formulating a suitable cam drive for a quad-cam engine. It is believed the sketches were produced as a precursor to designing and building a quad-cam 8-litre 90° V8 engine for a post-war military application. A similar architecture found its way into Baily's quad-cam V12.

Baily's drawings showing his ideas for a quad-cam duplex chain drive
© Copyright image - not to be reproduced without permission.

Claude Baily had been working on a quad-cam 60° since 1949/50 - perhaps earlier. By the February of 1951 a fully-working engine may have been running on the test bed. This 12-cylinder engine was later developed as an 8-cylinder variant for military use. The following quad-cam V12 performance data was recorded on the 19th February 1951.

Claud Baily's 1950/51 60° quad-cam 8-litre V12 engine performance data.
© Copyright image - not to be reproduced without permission.

The following picture shows Baily's data in his own hand. Was this an estimate/conjecture or are they figures actually recorded on the test bed?

Claud Baily's 1950/51 notes.
© Copyright image - not to be reproduced without permission.

In 1962, Baily was given the go-ahead to develop his design as a 5 litre V12 to challenge at Le Mans. Although primarily designed for racing, consideration was also given to using the engine in production cars. At least two years before the go-ahead, Baily's 60° V12 engine was being proposed as a future Jaguar engine with a range of possible capacities as the following memo from Claude Baily to William Heynes demonstrates:

5th December 1960 memo - "POSSIBLE FUTURE RANGE".
© Copyright image - not to be reproduced without permission.

The quad-cam V12 engine project was given the code "XJ6" - not to be confused with the saloon of the same name. "XJ6" followed on from "XJ5" which was the code name given to the Mk10 replacement (eventually to become the 420G). Two Mk.10 cars (XJ5/4 and XJ5/5) were to become mules for the production variant of the "XJ6" racing engine. The following memo confirms that six prototype engines were being developed.

25th November 1964 memo - "12 CYLINDER ENGINES".
© Copyright image - not to be reproduced without permission.

The first two engines (XJ6/1 & XJ6/2) were first assembled to almost identical specifications which included dry-sump lubrication and Lucas mechanical fuel injection. In April 1966 XJ6/1 was installed in the XJ13. The second engine, XJ6/2, was installed in a Mk10 Jaguar (XJ5/5 - manual gearbox) on 14th April 1965. It was converted to wet-sump lubrication although its Lucas fuel injection system remained. After six months of testing in the Mk.10, XJ6/2 was removed from the car and reunited with a dry sump for further test bed development. In March 1966 it's dry sump was again converted to enable fitment in a second Mk.10 (XJ5/4 - automatic gearbox). By this time it had acquired a sextet of SU carburettors. It ran for almost 35,000 miles in this car before it was removed and replaced in XJ5/5. It was finally removed from the latter car and placed on the test bed for further development/testing until it was put into store in March of 1969. It remained as a complete engine until I acquired it in 2010. It is now being rebuilt to its original specification and will be placed in my replica of the 1966 XJ13.

So, to answer the question "How many quad-cam V12s were built and where are they now?" SIX quad-cam V12 engines were built.

XJ6/1 The first quad-cam V12 built but only the second to leave the test-bed and be installed in a car (XJ4/1).  Damaged in 1967 and retained as a spare by Jaguar. 

XJ6/2 The second quad-cam V12 built and the first to be installed in a car (XJ5/5) Survived as a complete engine and sold by Jaguar in the mid 1970s. Currently under restoration to original specification (same build spec as XJ6/1).

XJ6/3 Only ever ran on the test bed in a variety of configurations. Has not survived.

XJ6/4 Built using cast iron block and ran on test bed. Has not survived.

XJ6/5 Internally modified to run as a V8. Ran on test bed for a short while in 1965. Surviving components are with a collector in the US.

XJ6/6 No records exist. It is believed this engine was never actually assembled.

XJ6/7 Built to trial a die-cast "open-deck" engine block.  Installed in XJ4/1 (XJ13) to replace its original engine when damaged in 1967. Remains in the car to this day.

XJ6/8 Built to competition spec with ultimate development of cylinder heads but never left the test bed. Cannibalised whilst in storage in 1969. Cylinder heads placed on XJ6/2 which remain with it until today. The engine block found its way into an XJ13 replica built by Bryam Wingfield for the collector Walter Hill. 

It is interesting to note that Jaguar's XJ13 currently has a die-cast block that differs from its original XJ6/1. This die-casting process is used to reduce costs and will have been more relevant for a production as opposed to competition engine. The following letter indicates the target casting weight of a V12 block (OXW 5620 is an experimental part number current at the time of quad-cam testing)

Die Casting Quote.
© Copyright image - not to be reproduced without permission.

The XJ13's rather poor power to weight ratio when compared with its likely Le Mans competitors may have contributed to this attempt to lighten its weight?

As Mike Kimberley recorded after a test of the XJ13 at Silverstone in 1967:

BHP per lb weight

Ferrari P4/ .210

Lola Chev/ .207

Ford Mk4/ .206

XJ13/ .177

It is also interesting to note that the engine currently installed in the XJ13 has a single OPUS 12 cylinder distributor. Its original engine, XJ6/1, as well as XJ6/2 were fitted with twin 6-cylinder distributors.

XJ6/2 Original twin distributors as originally fitted to XJ6/1.
© Neville Swales.

XJ13 single 12-cylinder distributor on XJ6/7 engine.
© Neville Swales.

The rebuilt XJ6/2 will, of course, be built using its original twin distributors. In 1966 Claude Baily was charged with pricing the OPUS system. The following letters give an interesting insight - comparing the various options under consideration.

© Copyright image - not to be reproduced without permission.

© Copyright image - not to be reproduced without permission.

© Copyright image - not to be reproduced without permission.

There are other differences between the XJ13's original engine (XJ6/1) and the one currently installed in the car (XJ6/7). One is the inlet manifold throttle bodies. The first photo shows the original (1967) arrangement with dual throttle bodies (and separate mounting plates - coloured yellow) and the second shows the current arrangement (photo taken 1973) with individual throttle bodies and a single mounting plate on each head. Note also the different cam cover treatment - the earlier engine has the "trademark" polished cam covers wheras the currently-installed engine has a crackle-black finish.

1967 (original car)
© Copyright image - not to be reproduced without permission.

1973 (rebuilt car)
© Copyright image - not to be reproduced without permission.

The time has come to consider the specification for the rebuild of the quad-cam V12 engine. The first important thing to consider was the means of driving the four camshafts.

As stated previously on this blog, the intention is to recreate an EXACT copy of the XJ13 as it was in its heyday in 1966/67 - WITHOUT its subsequent modifications which include its "delightful" 1970s-style flared wheelarches, alloy wheels and gear-drive to the cams. Contrary to common belief, gear-driven cams were not installed in the car until 1978 - a good 11 years after the project had been allowed to die. The XJ13 NEVER ran with gear drive to the cams in period - the cams were always driven by duplex chains. My original engine has duplex chain drive to the cams - as was the case with both engines originally installed in the XJ13.

This "gear-driven cam" myth became widespread by the publication of cutaway drawings such as the ones shown below. Indeed, Jaguar themselves began to believe their own myth.

Cutaway drawing of engine fitted to XJ13 in 1978.

Detail of partial gear drive to cams - part chain and part gears.

The confirmation that the XJ13 never ran with gear-driven cams in period can be found in Jaguar's own archive. The archive contains a series of engine test logs - a log for each of the six prototype engines assembled as quad-cam V12s. Of these six original engines, only three survived as complete units(although a fourth was subsequently built up from new and used parts left over at the end of the project and used by Bryan Wingfield in a XJ13 copy for the late Walter Hill). Two of the three engines remained with the XJ13 and I have the third. As well as these engine logs, a number of original reports and other documents have survived. The facts recorded in these documents can be used to accurately chart the progress of these engines. A good 45 years have elapsed since the project commenced and people's recollections of events all those years ago may be a little hazy - even those who were directly involved at the time. It is for this reason that I base my conclusions purely on the documentary evidence.

The logs confirm the XJ13 never ran with gear-driven cams in period as follows:

1. Only two of the six prototype engines have ever been installed in the XJ13. These are recorded as "No.1" and No.7".

2. The first engine to be installed in the XJ13 was "No.1". This unit was NOT built to competition spec and did NOT have geared cam drive.

3. After a spell of testing on the test-bed (conducted by Mr J Eastick) "No.1" was installed in the car in April 1966 - " ... engine handed to Mr Brookes for installation in XJ13 rear engined car..."

4. In the meantime, "No.7" engine was being developed on the test bed. This engine - No.7 - HAD been assembled with gear-drive to the cams. " ... 12/8/65 ... built to competition specification ...". Later that year, in December while the engine was still on the test bed, the timing gear on "No.7" engine was replaced by the timing gear from the "No.4" engine. " ... timing chain brackets, chains, sprockets, dampers from No.4 ...". "No.4" engine was the only V12 engine with a cast-iron block (the other engines were all alloy). "No.4" was not built to competition specification and had duplex chain drive to its cams. "No.4" may have been subsequently smashed up and has not survived.

5. For the remainder of 1966 and the start of 1967, the XJ13 continued its development powered by the chain-driven "No.1" engine. Meanwhile, "No.7"'s development continued on Jaguar's test bed with numerous references to the cam chain drive in its testing log.

6. On the 23rd April 1967 disaster struck! Norman Dewis missed a gear change at MIRA whilst testing - " ... unable to test for extended period. Dewis missed gear. Suspect bent valves ..." The XJ13's engine ("No.1") suffered extensive damage after the missed gear change. The "No.7" engine, still with chain-driven cams, was hurriedly prepared for installation in the car. On the 10th May 1967 "No.7" was removed from the test bed - still with chain-driven cams. Installation of "No.7" in the XJ13 commenced on 11th May 1967. "No.7" was recorded as still being in the car as late as July 1973 " ... engine in car for Silverstone demonstration run on 14/7/73 ...".

7. Meanwhile, "No.1" was returned to the test bed for further development/testing where it remained until 1978. In July of 1967, gear-driven cams were added to "No.1" while it was still on the test bed.

8. During this time, my engine, "No.2" continued to be developed both on the road and on the test bed. Indeed, it remained under development long after the other V12s had been removed/dismantled for storage. Development of "No.2" continued until 1969 when it was used to carry out comparisons with the road-car single overhead cam engine. It has the distinction of being the very first Jaguar V12 ever to run on the road and may have been the only engine to have reached the 502bhp @ 7500rpm falsely claimed for the engines installed in the XJ13. It is likely the maximum power developed by engines fitted to the XJ13 was a much lower 438bhp.

9. In 1978 disaster struck again ... " ... 3/7/78 (No.7) removed from XJ13 car after damage to 'A' bank cylinder head during warm-up for demonstration run at Daily Express March meeting. Engine known to have over-revved during missed gear change, would appear to be broken tappets or tappet guides, No.6 exhaust valve head broken off and jammed in seat ...". It was at this point, as late as 1978, the XJ13 was fitted with gear-driven cams for the first time - long after the project was dead, after its crash and after it had been "modified" for a life of demonstration runs only.

"No.1" engine remains with the XJ13 to this day.

In January of 2011, on a very cold January morning, the restoration of my quad-cam V12 began in earnest with a total stripdown and detailed examination. The task of rebuilding this important engine has been entrusted to David Butcher.

David can draw on his vast experience gained from many years of rebuilding Jaguar engines from the 1960s to date. He has had a long involvement with Jaguar engines since his days working alongside the late Ron Beaty at Forward Engineering. Although in "semi-retirement", David's skills are very much in demand today - particularly by racers and enthusiasts. David has worked on all variants of Jaguar's classic engines including the Group C and prototype Le Mans racers.

David Butcher starting work on the prototype V12.

We were privileged to be joined at the initial engine stripdown by Peter Wilson and Jim Eastick. Both Peter and Jim worked at Jaguar on projects associated with the XJ13 - Peter on the car itself and Jim on the prototype's V12 engines.

From left to right - Peter Wilson, David Butcher and Jim Eastick.

I was fascinated to learn from Jim Eastick that my engine has a direct connection with the legendary Ron Beaty as it was Ron who actually ran and optimised my engine on the Jaguar test bed. Beaty joined Jaguar and made his way up to being one of the all time greats at the works. He worked in the former competition dept and was experimental engineer for the V12. In the late 1960's Ron Beaty formed the company Forward Engineering which made him a household name in the Jaguar world, creating power units for British and world water speed records, Lister Jaguars (Beaty created the original Lister XJS with Brian Lister) as well as many track records both here and abroad. The original TWR XJS's were also "Forward " powered as were many small volume constructors like Panther. David Butcher worked alongside Ron Beaty at Forward Engineering and played an important role in some of Forward Engineering's various projects. Other notable "Forward Engineering Graduates" were Rob Beere and Carl Taylor of Rob Beere Racing.

While David worked on the engine, I was treated to an accompanying dialogue of recollections of life at Jaguar at the time of the project between Peter, David and Jim - memories sparked by details of the engine revealed as the stripdown progressed - recollections not only of the engine itself but also the many individuals involved at the time. Sadly many of these individuals are no longer with us. Jim also brought with him his personal notebook containing notes made while the prototype engines were actually being run on Jaguar's Test Beds - a book he kept very close to his chest!

Jim Eastick consulting notes made during prototype engine testing.

My engine was the second engine assembled and is believed to be one of only three engines surviving having left Jaguar as a complete engine. Two of the three engines remain with the XJ13. There is a fourth engine which was assembled from a collection of new and used parts left over at the end of the project and installed in a replica for the late collector Walter Hill by Bryan Wingfield. As the stripdown progressed it soon became clear that the engine was not only complete internally but was in quite remarkable condition despite its 40+ years of storage.

Head removal.

Jaguar's habit of liberally applying "Wellseal" to gasket surfaces was very much in evidence! Having removed the heads, the condition of the bores and pistons became apparent. Although there is slight surface oxidation on the crowns of the cast alloy pistons, this is to be expected on an engine that has been stored for this period of time. It does confirm that the engine has spent its last 40 years undercover and in dry conditions. The slight oxide buildup was only present on the pent-roof piston crowns and the remainder of the pistons was found to be in quite remarkably good and usable condition. The lack of any significant carbon buildup does tie up with the original testing logs which indicate the engine was only run for a short time on Jaguar's test bed before being removed for storage in December of 1969. The final bout of testing was for emmision comparisons with the SOHC production engine.

The cylinder block is a L.M.8 sand casting and has a sump face on the crankshaft centre line. This is in contrast with the later SOHC V12 which had a much longer "skirt" which helped increase block stiffness. The prototype engine is a solid casting as opposed to the die-cast "open deck" design of the later engine. This makes it a rather heavy engine which is difficult to manouevre by hand - ask me how I know!

Cylinder heads showing "tin" gaskets. In the foreground can be seen the original twin distributors. Twin distributors were used in the original 1966 XJ13 and were only replaced with a single "modern" V12 distributor during the car's rebuild in 1972/73.

Hemispherical combustion chambers.

The V12 cylinder head design is very similar to the 6-cylinder XK engine in basics such as valve operation with a few significant differences. In an attempt to arrive at a more compact and efficient combustion chamber, the chamber depth was reduced to 1.03" (from the XK's 1.30") and the included valve angle was reduced.

As explained by Jim Eastick, the V12 prototype engine has equal firing impulses along each bank and can be carburetted as an in-line 6 cylinder. The bore and stroke is 87mm x 70mm giving a displacement of 4991cc.

All prototype engines were fitted with twin 6-cylinder distributors. One of the many changes made when Jaguar rebuilt the XJ13 after its crash in 1971 was their replacement by a single 12-cylinder distributor. One of the two distributors, the "master", contained two sets of contact-breakers plus a centrifugal advance mechanism that served both distributors. The second distributor, the "slave", was simply a distributor for the H.T. current. My engine will be rebuilt with both distributors as original.

Jim Eastick explaining how he had added extra springs to the "master" distributor in an attempt to reduce points bounce during testing.

The heads on my engine are numbered 18 and 19. This confirms them as the ultimate development of the prototype cylinder head having an optimum subtended angle of 41 degrees to the valve axis with camshaft centres raised by 0.25". The cylinder heads remaining with the XJ13 may have never achieved the widely-reported maximum power of 502 bhp at 7,600 rpm achieved by an engine with this design of head.

The following picture shows the modified sump fitted to my engine. Although it is the engine's original racing dry sump, it was considerably modified in period to enable its fitment in the two Mk10 Jaguar "mules" for testing. The original gear scavenge/pressure in-sump gear pump was found to be in place but modified so that drive was transferred to a rear "wet-sump" pickup. The welded-up position of the original scavenge/pressure outlets can be seen at the front of the sump. The plan is to return the original sump to dry-sump specification.

Modified dry sump.

The four studs on the skirt of the block are used to not only mount the engine but also to provide a location for the rear trailing arms. There will be a corresponding pair of locating studs on the final sump. The engine/transaxle in the XJ13 supports the entire rear suspension.

Seen here is part of the duplex chain cam-drive arrangement - incidentally, as originally fitted to the XJ13 engines and not gear-drive as widely thought.

Chain-drive to cams.

The next few pictures show the sump being removed - revealing components not seen since the engine was assembled in Coventry in the late 1960s.

Preparing to remove the sump under the watchful eye of Jim Eastick.

Sump removed revealing combined scavenge/pressure pump and shaft used to transfer drive to the rear oil pickup. As with the later SOHC engines, a steel plate extends the full length of the crank.

Oil pump detail.

Chain drive to oil pump.

The engine has seven 3" diameter main bearings which means the later shells can be used (perhaps with slight modification to oil-holes). The big ends are unique which may cause some problems in finding replacements. When Jaguar recently rebuilt the XJ13's engine they found it necessary to increase the diameter of the conrod big ends to accept "off-the-shelf" bearing shells. This avoided a cost of something in excess of £20,000 to tool up for the prototype's unique bearing size. However, we have yet to fully explore whether or not the original size shells can be found. The crank pins are 2.187" diameter and are 1.20" wide to accept the side-by-side conrods. The conrods are offset 0.75" bank-to-bank. The crankshaft is made from forged steel and is lubricated using an end-to-end feed from grooves in the main bearings. The same sludge trap system as used on the earlier 6-cylinder XK engine was used with transverse oil feed holes. Although we have yet to confirm whether or not the crank was nitrided it is known that Jaguar used a EN 40 nitrided crankshaft in the competition V12.

David then began to remove the timing-chain cover so that pistons and crank could be removed.

Preparing to remove timing cover.

Timing cover removed.

The following picture shows detail of the lower two chains (four separate chains in total). One chain drives the oil pump while a second takes drive to intermediate sprockets - one for each head. Another sprocket is used to drive the twin distributors and Lucas fuel injection metering unit via a "Jackshaft". A hydraulic chain tensioner can be seen towards the bottom of the picture. The two top chains (driving the cams) are tensioned by an external nut applying pressure to a slipper.

The complexity of this chain layout was a factor in deciding to go with a SOHC layout for the production engine. The weight and cost could be reduced using a single chain drive with four sprockets compared to the prototype's four chains and twelve sprockets. Also, the noise level of the quad-cam layout was unacceptably high for a production engine. However, for racing purposes the quad-cam layout was preferred.

Timing chain detail.

Drive removed from oil pump.

Steel cover plate and scavenge/pressure pump removed.

Referring to original notes .....

Oil pump.

Removing slave distributor drive.

Distributor drive "jackshaft"

Piston sees light of day after 40 years.

All bearing shells were in remarkably good condition - confirming the engine's short time on Jaguar's test bed before the engine was removed for storage.

Journals also in good condition.

"Yours Truly" lends a hand.

Connecting rod still polished and shiny after all these years.

Preparing to remove crankshaft.

Jim Eastick remembering modifications to oiling system.

Detail showing "grooves" around oil holes on alternate big ends.

Slip-fit dry liners.

Crankshaft removed. Bearing shells were all in excellent condition.

Now that the engine has been stripped it can be given a detailed examination/measurement in readiness for its rebuild. As a matter of course things such as valve springs and (probably) valves will be replaced. After standing for more than 40 years it makes sense to replace items such as this - the thought of a detached valve in the rebuilt engine doesn't bear thinking about! Fortunately, we are well-blessed in the UK with skills and expertise to be able to build an engine such as this.

To be continued ...

As part of my research into the background of my prototype V12 engine, and as its rebuild looms (details to follow ...), I came across the story of a key man involved in its design - Walter T.F.Hassan, O.B.E.,M.I.Mech.E. What follows is the story of one of this country's most gifted designers of high-performance engines and a vital link in the XJ13 story.

Walter Hassan on his 90th birthday with fellow designers and veteran cars.

As previously revealed, the engine which will be installed in my recreation of the XJ13 is one of only three prototype engines originally designed by Claude Baily and developed by Walter Hassan and Harry Mundy which survived as complete units. Two of these engines are with the XJ13 and this third engine is presently undergoing a complete restoration to its original spec - a similar spec to the engine first installed in the 'original' XJ13. The most notable difference being that, wheras the engines originally installed in the 'original' XJ13 were not built to "full competition spec", the only surviving heads from the single engine assembled to this ultimate competition spec found their way onto my engine and remain with it today. This important engine represents a significant milestone in Jaguar's eventual V12 engine development - leading to one of the finest and most long-lived luxury car power units of recent years - a credit to the expertise of Walter Hassan. 

There is a "fourth" engine that was assembled from a collection of new and original parts left over at the end of the V12 engine project. This latter engine found its way into a Bryan Wingfield replica built for the late Jaguar collector Walter Hill.

There is no doubt that the quad-cam V12 prototype engines were all built primarily with racing in mind. As Walter Hassan wrote in his booklet summarising the development of the V12 engine:

It was clearly never the intention to install the quad-cam engine in a production car as, in Hassan's own words it would need to " fit into the same space as the six-cylinder engine without structural alterations to the body hull of existing models." The quad-cam prototype engine was too large and heavy to fulfil this role. Although my engine was installed in two Mk10 "mules" this was done as a means of further developing the quad-cam as a racing engine. In a filmed interview Hassan stated, " ... the engine was too big and noisy for a production car ...". (Click HERE to see the Hassan interview video). Soon after becoming involved in the V12 project, and after Jaguar took the decision not to race the XJ13,  Hassan began to formulate plans for a single-overhead-cam version more suited for road use.

Original 1976 booklet written by Walter Hassan for the Technical, Administrative and Supervisory Section of AUEW

Although the second engine built, my engine was ready for installation in a car long before the first engine because the latter encountered a number of problems during test-bed development as evidenced by the engine test records. The XJ13 car's development had been delayed and was not ready so my engine was installed in the first Mk10. The engine was installed in this car complete with Lucas mechanical fuel injection and modified dry sump (to clear the Mk10 cross-beam). By the time the engine was installed in the second Mk10 "mule" it had acquired a sextet of SU carburettors in place of the Lucas mechanical system. By all accounts, this produced an under-steering, nose-heavy, poorly-braking car with a limited turning circle (due to the width of the quad-cam engine) - albeit rather quick! This confirmed Hassan's belief that, although suited to racing, a more refined, lighter and more compact SOHC engine would be needed for road use.

But I am getting ahead of myself ... long before my engine's bark was heard in Coventry and was used to terrorise the Aston Martins on the M1 outside Newport Pagnell, Walter Hassan was taken on as an apprentice by WO Bentley. The year was 1920 and Hassan was a wet-behind-the-ears 15-year-old fresh from Hackney Technical Institute.

At this time, WO Bentley had only just moved into their first factory at the Welsh Harp Reservoir, Cricklewood in London. This area was rapidly becoming a centre of engineering excellence after the First World War had greatly stimulated industry in Cricklewood. Handley Page expanded considerably, and the French aircraft companies Caudron and Nieuport both had works in the area. In 1916 the School of Mechanical Warfare was set up in the fields between Dollis Hill Lane and Oxgate Lane as a proving ground for tanks. Amphibious tanks were tested in the Welsh Harp reservoir.

Women workers in an aircraft factory at Cricklewood during the First World War

the young Hassan's talents flowered very early on - in 1925 he prepared a Le Mans 3-litre Bentley for a 24-hour record attempt on the banked Montlhery circuit south of Paris, where it averaged over 95mph without problems. The special single-seater was built in 1925 to compete for world and international records at Montlhéry. It gained a World 12-Hour title in 1926 at 100.96 mph. WO Bentley himself described Hassan as, "very young, very keen and very ambitious".

1925 Bentley 3/4 1/2 Litre Le Mans Replica Tourer

It is reported that his "ambition" nearly cost him his life when Bentley returned to Montlhery in 1926 with the single-seater Bentley "slug" to attempt the first 100mph plus 24-hour record. "The works drivers, diamond millionaire Woolf "Babe" Barnato and jockey george Duller, had already covered over 1000 miles when Duller skidded on the banking. Shaken, he drove into the pit to allow Barnato to take over, but the "Babe" had gone off to eat, only the young Walter Hassan was present.
In his attempt to save the record attempt, Hassan leapt into the driving seat and drove off, managing only a third of a lap before the tricky handling of the "slug" sent the car skidding through the crash barrier. It rolled over, ending astride a ditch with Hassan apparently dead. "E's cooked 'is goose" a French bystander was heard to remark. The car was a write-off, and because Hassan was not a designated driver, any record would not have been officially registered anyway.
He recovered after three weeks in a private room in the American Hospital, Paris. It seems the fact that the hospital refused to accept any payment for Hassan's treatment endeared them to the "financially astute" WO Bentley.

The Hon. Mrs. Victor Bruce watches re-fuelling through the Le Mans style quick fill funnel during her record attempt at Montlhéry in June 1929.

In 1931, at the age of 26, Hassan joined the renowned Barnato who had pretty much funded Bentley since 1926 and was put in charge of Barnato's private garage at Ardenrun - Barnato's country house near Lingfield.

It was Barnato who, in 1930, accepted a challenge to race his Bentley against an express train, Le Train Bleu (the Blue Train) from Cannes to London. Barnato bet that he would drive his Bentley from Cannes to London and beat the train to Calais. After averaging 43.43mph during the 570 mile journey to Calais, Barnato crossed the Channel and finally reached the Conservative Club in St.James Street, London, beating the Blue Train to Calais by four minutes and winning his £200 bet.

Financier, motor racing driver and Chairman of Bentley Cars. Joel Woolf 'Babe' Barnato was born in Westminster, London, the son of Barney Barnato, an exceedingly rich man who made his fortune in the Kimberley diamond mines of South Africa.

Hassan developed a special 8-litre Bentley for Barnato - specifically for racing at Brooklands. Hassan used a 4-litre chassis frame which had assumed the identity of the 1929-30 6.5-litre Le Mans winner "Old Number One". The car crashed over the Brooklands banking in 1932 - killing its pilot Clive Dunfee. The car was subsequently rebuilt as a road car.

Portrait of Jack Dunfee and Woolf Barnato at Brooklands in 1929

Walter Hassan also created the Barnato-Hassan Bentley racer whose lap speed of 142.6mph was the second-fastest ever recorded at Brooklands. Hassan's achievements continued as he worked on the new ERA racing voiturette in 1936 after Barnato retired from racing.

In 1937 Hassan joined Thomson & Taylor of Brooklands. His main responsibility was to assist in the development of an advanced land speed record car designed for the legendary John Cobb by Reid Railton. It was Railton who told Cobb about the Bonneville Salt Flats and started the parade of LSR contenders to the Utah salts (then known as Salduro Salts). The year 1937 was a busy one, for Reid not only designed a Water Speed Record boat for Campbell that went 129.30 m.p.h, but an LSR car for Cobb based on 2 combined 1,250-b.h.p Napier Lion engines. The Napier-Railton captured the record in 1937, 1938 and 1947, and was the car that held the record longest in history, until the American assaults of the mid-sixties. Reid himself was at these runs; in fact, in 1939 he stayed in America, settling in Berkeley, California., and opening his new career by joining Hall-Scott Motor Co., makers of boat engines. He stayed with that concern, working on defense and war projects, through 1945, then quit to become a consultanr again. Among his first projects was readying Cobb’s pre-war car for the 1947 LSR attempt.

The Napier Railton on the track driven by John Cobb 1935.

It was in 1938 in the Brooklands paddock that Walter Hassan was approached by Bill Heynes of SS Cars. Heynes was looking for a chief engineer for his experimental department in Coventry. At the time, SS Cars were a rapidly growing company already selling 5,000 cars a year. In 1939 and the coming of the Second World War, Hassan turned his talents to developing carburettors for aero-engines at Bristol but returned to Jaguar in 1943 where he worked on scout vehicles which could be parachuted behind enemy lines.

In those final years of the war, while fire-watching in the company of William Lyons, Bill Heynes and Claude Baily, plans to introduce a new twin-cam engine were sketched out. At the end of hostilities, SS Cars was renamed Jaguar Cars. Hassan brought in an old friend from his Brooklands days - "Lofty" England - as Service Engineer. England was later to succeed William Lyons as Jaguar's Chief Executive.

The Jaguar twin-overhead-cam XK engine.

The new engine was finally unveiled to the public in the sensational 3.4-litre XK120 sports car at the London Motor Show in October 1948. For the first time, these cutting-edge twin-overhead-cam engines became accessible to the general public. The same basic design was employed by Jaguar for more than 40 years - a further testament to Hassan's talent.

Hassan's career didn't end there - he joined Coventry Climax as Chief Engineer and was instrumental in developing the legendary "FW" (featherweight) fire-pump engine into one of the most successful competition units of its day. Two specialised Grand Prix engines followed under Hassan's direction - the FPF 4-cylinder and FWMV V8. The FWMW began winning races in 1962 with Jim Clark. These engines went on to give Coventry Climax a staggering 96 Formula One victories and four world championships between 1958 and 1966. Stirling Moss scored the company's first Formula One victory in Argentina in 1958, using a 1.9-liter version of the engine. The FWE engine was also developed for the Lotus Elite and this enjoyed considerable success in sportscar racing, with a series of class wins at Le Mans in the early 1960s.

Coventry Climax FWMV 1500cc V8 Formula 1 engine in a Lotus 24.

Walter Hassan returned to Jaguar as director in charge of power units when Coventry Climax was purchased in 1963. He recruited Autocar's technical director Harry Mundy as Chief Development Engineer. In December of 1963 these two oversaw the assembly of my prototype engine - the first bark of this engine was heard in Coventry on the test-bed in January 1964.

I look forward to hearing Hassan, Baily and Mundy's remarkable engine roar once again ...... watch this space .....

On the 3rd June 1965 an internal "Instruction to Proceed (XJ13 Car)" was issued by Jaguar’s Bob Knight – it started, “Build one prototype competiton car …”. Responsibilities for all aspects of the car’s design were allocated – the responsibility for the body being given to Malcolm Sayer, Phil Weaver and Bob Blake.

The body was to be, “Light alloy skin on monocoque structure. Comprising of three main sections”. These three sections were:

• “Body Front Structure” (main skin, front bulkhead, headlamp diaphragms, air-ducts for radiator/brakes etc, internal structure to suit 1964 Jaguar Lightweight E-Type independent front suspension and a boot lid).
• “Body Centre Structure” (floor & sills, fuel & oil tanks, seat back bulkhead, doors and windscreen).
• “Body Rear Structure” (main skin, engine cover, spare wheel, cooling ducts for transmission & brakes, rear lid and rear valance).

Other responsibilities were allocated as appropriate. Rather telling was the comment “For the first car only” which does confirm the prototype XJ13 was planned to be one of many.

By the June of 1965, the quad-cam V12 engine project for the XJ13 was well underway – with the emphasis very much on racing. The first V12 engine to be fitted to any car was my engine (engine number 2) which was fitted to a car codenamed “XJ5/5” – XJ5 being the code name for the Mk10 successor. This engine was fitted to this sable-coloured “test mule” in April 1965 – complete with Lucas Mechanical Fuel Injection and modified dry sump - some two months before the XJ13’s “Instruction to Proceed” was issued. The engine in the “test mule” was built to the same specification as the first engine (number one) which was to be installed in the XJ13 a year later in April 1966.

Overall responsibility for the shape was given to the late Malcolm Sayer – the man already responsible for the Jaguar C-Type, D-Type and later to be responsible for the iconic designs of the E-Type and XJS.

Malcolm Sayer, 1916-1970

Malcolm Sayer was a student of aerodynamics at Loughborough University’s Department of Aeronautical and Automotive Engineering in 1938. He was one of the first designers to apply the principles of aerodynamics to cars with his scientific calculations, creating some of the most beautiful forms of the era. Sadly he died in 1970, at the relatively young age of 54.

After graduating from Loughborough he joined the Bristol Aero Company where he worked on various projects including their radial engine. One of Sayer’s colleagues at Bristol was Phil Weaver who was later to work to take charge of Jaguar’s Competition Department and work alongside Sayer on the XJ13. In an interview with Phil Weaver, Paul Skilleter (well-known Jaguar Historian and Author) recorded Weaver’s recollections of his time with Sayer at Bristol.

Malcolm Sayer joined Jaguar in 1950 and his talent was soon recognised. One of his first tasks was to design a suitable body for Jaguar’s XK120C (the “C-Type”). The chassis had already been designed by Jaguar’s Technical Director Bill Heynes. Sayer worked alongside Bob Blake who had been given the responsibility of producing a body. Sayer brought his aerodynamic skills to bear on the project and added a large element of science to the body design. He was one of the first to use wind tunnels in automotive design and photographs exists of the various small-scale models he had made to investigate the aerodynamic characteristics of his various designs.

Norman Dewis, Jaguar’s renowned Chief Tester, joined Jaguar not long after Malcolm Sayer and recalled how Sayer worked:

A number of contemporary sources cite Sayer’s habit of drawing a full-size car on the walls of his office or even with chalk on the floor. I don’t doubt that some of his initial designs for the XJ13 were done in this way. He had at least one small-scale model made up for testing before Bob Blake began the task of clothing the chassis/monocoque.

Sayer’s final designs were “formalised” as side, front, rear and plan view documents which may have become internal “standards” for his designs and used for things such as centre-of-gravity studies etc. The detail shapes of compound curves etc were established mathematically using a technique peculiar to Sayer.

Examples of these final standardised documents are shown below:

XJ13 “dimension summary”© Jaguar Heritage

In late 1967, after he had designed the XJ13, Malcolm Sayer designed three more V12 mid-engined sports racing cars. The drawing above shows one of these designs in the form of a “dimension summary”.copy; Jaguar Heritage

It is interesting to note that Sayer’s original design as shown above differs in many respects from the rebuilt “original”. It is my aim to reproduce the XJ13 exactly as Sayer had intended and before the addition of “1970s wide wheels/wheelarches” and other “updates”. It is important to me to recreate the car as close to its original specification as possible – not only to satisfy requirements for potential racing against cars of the period, but also because the historical significance of the surviving original prototype engine demands this. After all, Jaguar had always intended to produce more than one car and I feel an authentic copy could be considered to be a “continuation” in line with Jaguar’s original intentions.

Malcolm Sayer was very much a man “ahead of his time”. There is much talk nowadays of Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) but it seems that as early as the 1950s Sayer had developed his own longhand version of similar techniques. He kept his calculations and means of representing complex shapes mathematically very close to his chest and there is little information on his methodology available today.
Paul Skilleter reported that Cyril Crouch, who worked in the Body Drawing Office in Sayer’s time, recalls him “using Chambers seven-figure log tables to calculate all the shapes, as one would do on a computer now.”

Bob Blake had joined Jaguar from Briggs Cunningham and was a legendary body-builder. He was able to interpret Sayer’s data and successfully translated his drawings into the full-scale XJ13. He was joined in this task by Roger Shelbourne and Geoff Joyce. Peter Wilson also worked on the car and was responsible for making some components of the car and chassis. Wilson confirms that, contrary to popular belief, the original car wasn’t built by Abbey Panels – their involvement was limited to “the fabrication of skin panels to our formers, and roller-seam welding of the inner sill panels to the main floor and outer sill sections.”
Peter, in his book “Cat Out Of The Bag” goes on to say,

Much of this data has survived – including the precise location points of items such as suspension components, steering rack, anti-roll bars in 3D space. This data will be used in the construction of my 1966 XJ13 copy. The main difference being that technology allows us to carry out this operation on a computer screen before the actual car is manufactured.

To help achieve a faithful copy of the original design, the technique of 3D scanning coupled with digital techniques to incorporate data from period photographs, original technical drawings and eye-witness accounts is being used.
An example of how digital data can be built up from an original document (in this case an accurate drawing used in 1965 for a centre-of-gravity study) is shown below. The pictures show initial work on reproducing the original centre monocoque structure.

© Neville Swales
Not to be reproduced without permission.

© Neville Swales
Not to be reproduced without permission.

© Neville Swales
Not to be reproduced without permission.

This digital data can be supplemented and cross-referenced with original photographs, reports and original technical data – as well as the “original” prototype. Once the information has been captured, it is possible to estimate things such as weights, roll-centres, centre-of-gravity etc. It is also possible to virtually “trial-fit” components to reduce the possibility of an error during the actual build.

Once sufficient digital data has been assembled and the on-screen 3D images have been verified with photographs etc, the next step will be to use the data to produce a physical scale model using CAM techniques including the use of a 3D printer. The scale model can be painted in the correct shade of 1965 BRG (British Racing Green), handled and verified for accuracy. It also gives an opportunity to see how the light catches the car in comparison with period photographs and the current “original”. Once this has been accomplished, the digital data can be used to manufacture millimetre-perfect full-scale formers and bucks – even to the extent of pre-marked or drilled rivet locations.

As well as being able to use these powerful techniques to faithfully reproduce the original car, they can also be used to reproduce unobtainable and unique parts such as cylinder heads etc. The following picture shows this scanning technique in action on the prototype engine:

© Neville Swales
Not to be reproduced without permission.

The item to be scanned (anything from a small component to a full-size car) is covered in a non-reflective white powder. Small adhesive dots are applied across its surface and the item is laser scanned. The small dots allow the sophisticated software to locate specific points in 3D space. Internal passageways may be scanned using similar techniques using lasers on probes.

Manipulation of the resultant data and production of a final digital representation of the scanned item is a skilled operation. Once the item has been captured in this way, faithful clones can be reproduced using computer aided manufacturing techniques.

My previous post looked at the development of the quad-cam V12 – I now look at how this evolved into the first single-overhead-cam V12 engine.

Much has already been published elsewhere – not least of all by renowned authors Skilleter, Whyte, Porter, Viart/Cognet et al. I hope to add to this body of knowledge with my own small contribution on aspects that may not have been already documented elsewhere.

V12 in 5.3 litre Series 3 E-Type guise.

In the mid-1960s, and coinciding with the British Motor Corporation takeover of Jaguar (to become British Leyland), the instruction was given that Jaguar were to withdraw from racing. This, of course, affected the XJ13 Le Mans project and further development of the racing car and its competition engine was curtailed.

As there was now no need for a competition engine, the emphasis switched to developing the V12 as a production engine. In a production engine, maximum power is less important than low and mid-range torque – allowing Jaguar’s saloons to waft along in effortless silence.

The downdraft inlet port arrangement had been found to be sub-optimal for the Jaguar engine. However, the sheer width of the quad-cam unit would have made the addition of a sidedraft arrangement impractical.

There were two other areas of the quad-cam that could be inappropriate for a production engine – the two-stage chain drive and its use of twin distributors. The two-stage chain drive used in the quad-cam engine proved to be rather noisy and, although acceptable in a competition engine, was inappropriate for a production engine. During the development of the twin-cam, a single engine (No.4) was assembled with a cast-iron block. However, the weight penalty was too great. It is not believed that this cast iron block has survived – although it may have found use as a ship’s anchor …

Comparison of single- and twin-cam chain drive mechanisms.

There were distinct advantages to using a single-cam layout rather than twin-cam:

1. There is a cost saving with the simpler design.
2. There is a significant weight saving (approximately 16lbs per head) if a single chain drive using a single sprocket is used rather than four chains and twelve sprockets – not to mention the smaller head castings and fewer camshafts etc.
3. The overall noise level is reduced.
4. The engine runs more smoothly with only two cams rather than four.
5. The greater width of the “Vee” allows the fitment of a single 12-cylinder distributor and other auxiliaries such as air conditioning compressor.
6. The overall width of the engine is reduced (particularly across the exhaust manifolds) which allows for greater wheel movement and a reduced turning circle.

Comparison of the bulk of a twin-cam vs single-cam arrangement.

Some trials were made with a partial gear-drive to the camshafts but this was unsuccessful and wasn’t adopted.

Changes were also made to the cylinder block. Wheras the twin-cam engine had a solid top deck, the later single-cam engine had an open deck. As well as weight savings, the latter design meant the block could be die cast to save money – an important consideration at this time in Jaguar’s history. Also, wheras the twin-cam engine sump face coincided with the crankshaft centreline, the single-cam engine’s sump face was much lower. 

Final cylinder block design showing the “open” deck and receptacles for cuff type push-fit liners. This picture is actually of a block that was used to create a coffee-table!

Perhaps surprisingly, it was found that the assembled non-decked cylinder block, with its associated webbing, was more rigid than the solid deck design of the twin-cam block.

Single-cam cylinder block from beneath showing main bearings and studs.

Just before the end of 1969, it seems that exhaust emissions were compared between the most highly-developed twin-cam competition engine (No.2) and the new single-cam production prototypes. It may have been found that the competition engine was more efficient in emission terms but other considerations will have weighted the decision towards a single-cam arrangement.

A number of single-cam prototypes were assembled and trialled between 1971 and 1977 – development continuing long after the introduction of the new single-cam engine in the Series 3 E-Type of 1971. As well as being developed on the test bed, these prototype engines were fitted to saloon cars for road trials.

Details of a selection of these prototype V12 single-cam engines are as follows:

Other projects – at least three with a 4-valve twin-cam arrangement – were also trialled between 1974 and 1978. The findings and data from these trials will have been fed into the ongoing V12 project. These engines were “slant six” twin-cam engines of between 3.6 and 3.8 litres capacity.

The following chart gives a comparison of performance of the two engines (5 litre twin-cam competition and 5.3 litre single-cam production).

Power curves of single and twin-cam engines.

In the above analysis, each engine used a Lucas mechanical fuel injection system with individual intakes and open exhausts – must have made quite an impressive noise at peak revs …

The single cam engine gave a much better performance up to 5000 rpm where its power reached a healthy 360bhp . The twin-cam competition engine, however, really came into its own above 5000 rpm and achieved over 500bhp @ 7,500rpm.

It is interesting to note that while looking for cost-cutting measures, Jaguar decided to inset the valves by 0.050” in the flat single-cam cylinder head. They could save money by doing this because there was then a higher permissible speed for the cutter used to dress the heads. This meant they could speed up this part of the process. Their static air tests indicated this wouldn’t make any difference to power. However, this cost-saving measure did reduce power in practice as can be seen from the following chart.

Curves showing effect of valve-seat insert depth.

Jaguar looked at various ways of fuelling their new engine – ranging from Lucas mechanical injection as used on the competition engine to carburettors. The first production engine, as fitted to the Series 3 E-Type used carburettors although this quickly gave way to a fully-electronic system to meet the demands of emission control and performance. The system used on the first single-cam injected engines was a fully-electronic fuel-injection system as jointly developed by Lucas and Bosch. The fuelling system continued to evolve throughout the V12’s history.

Single-cam engine showing carburettors (left) and petrol injection (right).

Although originally conceived as a competition engine to keep Jaguar at the forefront of sportscar racing, the possibility of eventually fitting the engine into production cars was always at the back of Lyons’ mind. However, up until the mid 1960s, the emphasis was primarily on competition and racing. This emphasis changed in the mid 1960s towards a “production engine” and the result was the long-lived single-overhead-cam V12. Although many compromises were made along the way, the first production V12 became a commercial success and went on to power a range of Jaguar saloons and sports cars.

I am proud to own an engine that was developed at a time when racing was its main reason for existence. I hope to sympathetically restore this engine and place it in an appropriate home – a copy of the XJ13 Le Mans racer as it was in the mid-1960s – perhaps even fulfilling its competition intentions.

Watch this blog!

Last month I made a post looking at the origins of the V12 – this month I look at the development of the V12 in a little more detail.

Before the V12, Jaguar’s racing and practically all road cars were powered by the powerful and renowned XK straight-six double overhead-cam unit. This engine had its origins in pencilled sketches drawn during the London blitz by Sir William Lyons and his engine designers; William Heynes (Chief Engineer), Walter Hassan and Claude Baily. These sketches and original designs were followed by working prototypes as early as 1943. The first 3,442cc production unit saw the light of day in the beautiful XK120 of 1947. The same basic engine continued production into the 1990s.

1947/1948 Jaguar XK120.

3,442cc Jaguar XK engine.

XK engine cross-section.

This engine went on to power Jaguar to a number of famous Le Mans wins. However, as early as the mid 1950s, the pace of international racing engine development led Jaguar to believe they needed to develop a successor to the XK engine to keep them at the forefront of racing. The Le Mans Sports Car Regulations at the time dictated the maximum capacity of the new engine – up to 5 litres. The Jaguar engineers agreed that the maximum power and tuning potential could be achieved with either a 8-cylinder or 12-cylinder “Vee” formation. The current XK engine had a relatively long stroke and the ability to achieve greater power by running at higher revs was compromised by this design. The XK's cylinder bore of 83mm and stroke of l06mm resulted in a piston speed of 3,820 ft./minute at 5500 r.p.m. – much faster and the engine integrity could not be guaranteed. It was decided that the future engine would have a reduced stroke of 70mm which would allow the engines to run safely up to 8,500rpm.

In around 1965, the project became reality when a number of V12 cylinder blocks and associated components were commissioned. These blocks were used to build up two types of engine – one with internal modifications made to allow a specially-modified crankshaft, lacking two “throws”, so the unit could function as a V8; the second was a full V12.

It is believed that only one of the original “V8” engines has survived. Although not salveageable and not able to be made to run either as a V8 or V12, it survives as a display model. The following picture shows this engine as it appeared in the collection of the late Jaguar collector Walter Hill in the 1980s:

V12 prototype block internally modified to run as a V8.

My previous post on the V12 made reference to the fact that, of the originally-planned eight V12 engines, only four are known to survive today. Two (Nos.1 & 7) remain with the Jaguar XJ13 Le Mans prototype, one (No.2) has survived as a complete engine and is in the process of a full restoration prior to being placed in an authentic recreation of the original 1966 XJ13. The fourth V12 (No.8) was placed in a rather inaccurate XJ13 copy – made by the well-known and talented car builder Bryan Wingfield and sold to the collector Walter Hill.

In Wingfield’s own words (as reported in “Supercar Classic” magazine) – “I got a call from somebody I knew at Jaguar who told me that there were a couple of old prototype engines lying around which were of no use to anybody else, and asked whether I was interested … I had to buy those V12s through another engineering company.”

The Wingfield copy survives today as a running car – albeit with “Ford GT40-inspired” chassis and an approximation of the XJ13 body shape. The engine itself was bought as “a box of bits” and was made up from assorted original and new parts. The most desirable feature of this engine, the only heads with the ultimate development of intake angle (41 degrees), were removed from the “Wingfield” No.8 engine some time before its sale and fitted to the No.2 engine by Jaguar in 1969 and remain with the No.2 engine to this day.

V12 prototype twin-cam engine - stages of inlet port angle development. Greatest power was developed with a 41 degree inlet angle.

V12 prototype twin-cam engine – original inlet port angle (left) and final angle (right).

It was known that a V8 configuration needs a two-plane crankshaft with wide outer crankshaft balance weights to run smoothly. A V8 firing sequence is also not as efficient as a V12 if carburettors are used. In comparison, the V12 engine has equal firing impulses along each bank and can be treated as two sets of 6-cylinder engines as far as carburation is concerned. The V12 engine is inherently smoother than a V8. As well as these technical reasons for favouring a V12 over a V8, the USA car market was very important to Jaguar. It was felt that a V12 would have greater appeal than a V8 in this market.

The first V12 prototype was assembled in 1964. The prototype engine main features were:

• Twin overhead cam per bank
• 87mm bore x 70mm stroke
• 4,991cc capacity
• LM8 (aluminium) sand cast cylinder block
• Sump face on crankshaft centreline
• Top deck with flanged split rim cast iron liners
• Seven main bearings of 3.0” diameter
• Side-by-side connecting rods offset 0.75”
• 2.187” diameter crank pins
• Forged steel crankshaft with eight balance weights
• Crankshaft lubrication end-to-end feed fed from grooves in the main bearings
• Crankpins using sludge trap system used on the XK 6-cylinder engine and transverse feed holes
• EN 4A nitrided crankshaft

The following picture shows the second engine that was assembled in 1964 – as it is today.

V12 prototype twin-cam engine – with Peter Wilson (Jaguar Competitions Department 1961-1966) – complete with ultimate development of cylinder heads.

The prototype V12 cylinder head design was very similar to the tried-and-tested XK 6-cylinder head design but with a number of important differences.

The depth of the new combustion chamber was shallower (1.03” versus the XK’s 1.30”) and the included valve angle was more narrow (60° versus 70°). The combination of shallow combustion chamber and narrower angle was theoretically more efficient.

The following comparisons were made during development:

Competition and production versions of the twin-cam engine were developed at the same time. They were all basically similar except for things such as valve and port sizes and camshafts. Ideally, the prototype engine would have employed the use of transverse inlet ports which became the norm for equivalent competition engines being built by Ferrari and B.R.M. This was found by Jaguar to be a more efficient layout for their engines but it would have been impossible to fit a V12 engine with transverse ports such as those on the XK 6-cylinder engine, with an adequate induction tract length, within the confines of an engine bay – even that of the Mk10! While the competition version was being developed, Lyons and Hassan kept in mind the need to eventually fit a version of the engine in a production car.

During development, Jaguar found that the two stage chain drive was not completely reliable and the noise level was deemed unacceptable in a sophisticated saloon car. For this reason, a partial gear-drive was proposed for the competition engine camshafts as in the following diagram:

Camshaft drive (with gears) proposed for the competition engine.

However, this arrangement was never fully developed. A single engine was completed to this specification and was run on the test-bed. However, it remained in storage after the Le Mans project came to an end and was not fitted to the XJ13 car until 1978 when a missed gear necessitated an engine change – long after the project had ceased and the rebuilt XJ13 was only used for demos etc. For all its development life, the XJ13 ran with duplex chain drive to its camshafts.

The original engines were fitted with twin distributors which were found to be troublesome. One incorporated two sets of contact breakers plus the centrifugal and vacuum advance mechanisms for both; the other was used simply to distribute the HT current. At high engine speeds difficulty was experienced in matching the timing of the two sets of contacts and the variations were deemed unacceptable.

The following picture shows the original twin distributors as still fitted to the surviving engine number 2:

Twin distributors fitted to surviving V12 prototype No.2.

As may be apparent from the picture, it would have been difficult to fit a single 12-cylinder distributor in the “Vee” and so this twin-distributor arrangement continued throughout development. Around 1973, at about the time the crashed XJ13 was rebuilt by Jaguar, they were able to modify and fit a single 12-cylinder distributor and also updated the ignition system to OPUS (Oscillating Pick-Up System). A twelve-cylinder engine running at 6000 rev/min requires a spark rate of 600 sparks/second which is well above the capability of a conventional make and break “points” system (400 sparks/second). OPUS uses an electro-magnetic pick-up and electronic solid-state switching, mechanical delays are eliminated. The prototype engines were subjected to extensive testing – not only in cars (including the XJ13) but also on the test-bed. My own engine, No.2, was also fitted to two Mk10 Jaguars. These big and heavy cars, one white and one sable, were used for road trials as the original XJ13 may have been rather too conspicuous! There are many stories surrounding these two cars including a road test by “Wilkes” of Motorsport magazine who was allowed a test drive on the understanding he never opened the bonnet to see what was inside! Retired ex-Jaguar employees also tell stories of how the cars were used to surprise and embarrass the Aston Martins being tested on the M1 motorway around Newport Pagnell …

The following picture shows this engine fitted with six carburettors for these road tests. Close examination reveals its origins as the dry sump originally fitted in 1964 (modified to wet sump for fitment in the Mk10s).

Archive photo of No.2 V12 prototype – as fitted to Mk10s.

Towards the end of the V12 project the emphasis switched from racing to powering a production saloon. This eventually led, via prototype single-overhead cam V12 engines of 6.4 and 5.3 litre capacity, to the final 6.0 litre HE engine of the mid to late 1990s.

Developments from the quad-cam racing engine to the final single overhead cam engine will be covered in a future post.

To be continued ….

Lucas Fuel Injection

Fuel supply to the original 1966 XJ13 was managed by Lucas Mechanical Fuel Injection.

This system was retained by Jaguar when the car was rebuilt in 1972/73 and remains with it today. The heart of the system is the Lucas metering unit which sits in the "V" of the engine and distributes fuel to each of the 12 cylinders.

The following picture shows the unit in-situ in the car today:

Lucas Fuel Injection unit fitted to the "original" XJ13

The unit is belt-driven at half engine speed using a cog provided at the end of the distributor drive. The following picture shows the cog and mounting points on my engine (prototype engine No2) - just crying out to have a metering unit fitted!

Mounting point for Lucas Fuel Injection metering unit

This type of fuel system was "state of the art" in the 1960s and was fitted to many Ferrari and Maserati racing engines of the time. Finding an original unit proved to be very difficult. Although I actually succeeded in tracking down an original unit which the owner claimed had been removed from the original XJ13 during its rebuild in 1972, it turned out to be so badly damaged and corroded that renovation would not have been possible.

These units are manufactured to tolerances of less than one tenth of a thou and are absolutely critical to the efficient running of the engine. Bearing this in mind, I decided to commission a new unit - built to the original specification. I was fortunate enough to be able to make contact with one of the few engineers capable of carrying out such a task and I am now the proud owner of a brand new, original specification metering unit. It was pleasing to find that the skills to make the units are still available in the Midlands - not too far away from Coventry. These units are truly "works of art" and I look forward to the day when it can take pride of place atop my V12 prototype engine.

Newly-manufactured Lucas Fuel Injection Metering Unit.

Newly-manufactured Lucas Fuel Injection Metering Unit.

The Lucas petrol injection system has been outstandingly successful on high performance cars, particularly in the international racing field. During 1966-67 the first three places in almost every Grand Prix event were held by cars equipped with a Lucas petrol injection system.

1969 Lucas Ad.

A conventional carburettor is not required in the petrol injection system. Instead fuel is injected into each of the 12 air-intake ports by means of this high-pressure metering device.

Some of the more important advantages to be obtained from the use of petrol injection are:

• Reduced Fuel Consumption - A more economic use of fuel, because the quantity injected into the cylinders is closely regulated to suit the engine operating conditions.
• Smoother Running at Low Engine Speeds, and Better Acceleration - Engines fitted with fuel injection equipment accelerate quicker and have greater flexibility, particularly at low engine speeds.
• Increased Performance - A complicated manifold is not required, so that the air intake is greater than normal. This ensures improved volumetric efficiency and hence increased power.
• Cleaner Exhaust Emission - As there is almost complete combustion in the cylinders, the amount of unburnt hydrocarbons and carbon-monoxide is reduced. The result is ‘cleaner’ exhaust emission.

Original Lucas Ad.

The amount of fuel in each injection, and the frequency of the injections, is controlled by the metering distributor and mixture control unit. The mixture control unit regulates the amount of fuel in each injection, in accordance with the requirements of the engine. The function of the metering distributor is to inject fuel into each individual inlet by a system of shuttle-metering. The two component parts - the metering distributor and the mixture control unit - are a “matched” pair.

The metering distributor consists essentially of two parts; the rotor and the sleeve. The rotor has two radial ports, which lead to a centre bore containing a shuttle - which is movable between two stops (one fixed and the other adjustable). The sleeve has fuel inlet and outlet ports. The rotor fits inside the sleeve and is connected to, and driven by, the engine.

A critical component of the metering unit is the "fuel cam" - a lever which is connects the accelerator linkage to the metering unit and controls fuel supply to the engine as required. The following drawing shows the design of fuel cam as originally fitted to the XJ13.

Drawing used to manufacture original XJ13 fuel cam. Drawing produced by George Buck of Jaguar in 1966. © Jaguar Heritage.

The profile of this cam is absolutely critical to efficient running of the engine and a number of different profiles were tried out at different times during engine test-bed development.

The following extracts from a report by George Buck in April 1966 confirm the final fuel cam specification used when the engine was first installed in the XJ13:

Extract from George Buck April 1966 report. © Jaguar Heritage.

Extract from George Buck April 1966 report. © Jaguar Heritage.

Extract from George Buck April 1966 report. © Jaguar Heritage.

To be continued ....

Part One - Origins

For 25 years, between 1971 and 1996, Jaguar’s smooth and refined V12 power unit powered the Series 3 E-Type as well as a range of luxury saloons. Right from the outset the engine was designed with enormous tuning potential reserves and, in racing form, powered cars such as the Le Mans winning TWR prototype racers. Its tuning potential was taken to extremes in the world of offshore powerboat racing as well as drag racing.

Of course, the production V12 engine was not a new idea – the first production use of a V12 was as early as 1915 in Packard’s “Twin Six”.

Other manufacturers such as Fiat (7 litre V12) and Daimler (“Double Six) followed. V12-equipped cars soon proliferated and offerings were available in America from Auburn, Cadillac, Lincoln, Packard and Pierce-Arrow. The Germans followed suit with the Horch and Maybach. In 1930 Tatra of Czechoslovakia offered a 6 litre side-valve V12.

One thing all these cars shared was the association with “refinement” and “luxury” that a V12 configuration offers. This reputation was further enhanced by Hispano-Suiza’s use of a 11.1 litre V12 and Rolls-Royce’s 7.3 litre Phantom III. Early engines tended to have push-rod actuated valves although, just before hostilities commenced in 1939, W.O. Bentley designed a high-revving 4.4 litre for Lagonda with valve-gear very similar to the later Jaguar’s. Since 1945, the V12 became associated with quality Ferraris, Lamborghinis and Maseratis – especially in racing applications.

Jaguar’s V12 does have the distinction of being the first British manufacturer to emerge from WW2 with the first British V12. But why did Jaguar choose the V12 configuration? According to Walter Hassan, OBE and Harry Mundy, both credited with Jaguar’s V12, said the V12 layout gives perfect balance which allows high-speed running and the power potential which accompanies this.

Jaguar’s Walter Hassan (Chief Engineer – left) and Harry Mundy (right)

At the time, this was an important step for Jaguar. They invested over £3 million in tooling for mainstream manufacture of their engine – without an “economy” model to fall back on if the world decided that large capacity V12 engines were not the way forward. It is no coincidence that, early on in the V12 prototype project, alternate configurations such as a V8, slant-6 and straight-4 designs were trialled.

Jaguar had first considered a V12 as early as the 1940s. Claude Baily realised that a replacement for the 6-cylinder XK engine would eventually be needed – particularly if Jaguar were to continue their racing successes in the face of fierce competition from Ferrari and Ford.

In 1964, a first formal “Instruction To Proceed” was issued giving the go-ahead to build a number of V12 prototype engines. A second instruction was given in April of 1965 by Claude Baily for this engine to be installed in the planned prototype Le Mans racecar – the XJ13. In June of 1965 a further “Instruction To Proceed” was issued for construction of the XJ13 itself. The plan was to develop and install this engine in the XJ13 with the aim of repeating their successes at Le Mans in the 1950s. The emphasis of this V12 engine project was very much on racing from the outset – with the possibility of a production engine arising from this experience.

“Instruction To Proceed” © Jaguar Heritage

The first of these engines (engine “number one”) was assembled in July 1964. In common with all previous Jaguar projects, the prototype V12 project was given an internal code. The code for this project was “XJ6” – not to be confused with the later car of the same name!

XJ6 Project - Engine Log © Jaguar Heritage

Conducted in great secrecy, Jaguar’s Competitions Department and Engine Development Department kept meticulous records for each of the engines built, developed and tested. Thanks largely to the efforts of Jaguar Heritage, many of these records have been preserved and safely archived. The detailed log books for all but one of these “XJ6” engines survive (although the “missing” log book may, in fact, be for an engine that never existed as a complete engine). The first prototype V12 was assembled in July of 1964 (engine number one).

XJ6 Project - Engine Log © Jaguar Heritage

In total, it is believed that six complete engines were assembled as part of the XJ6 project. One of the six was assembled using a cast iron block (engine number four – not believed to have survived testing) although the remainder were cast alloy. It was common practice within Jaguar in the 1960s to scrap engines and components when no longer needed and, of this original six, it is believed that only four survive today. Two of these engines (numbers one and seven) remained with the XJ13, one had a privileged existence following extended development (number two) and one was built up from a collection of new and used spare parts long after the project had ceased (number eight).

All these engines were initially assembled with dry sumps and duplex chain drive to the camshafts. The only exception was engine number one that had a gear-driven camshaft arrangement fitted after the XJ13 development had pretty much ceased – this modified engine was fitted to the XJ13 as late as 1978 by which time the car was only wheeled out for demonstration runs etc. For all of its active development life, the XJ13 was powered by engines with duplex chain drive.

The engine blocks themselves were cast by the West Yorkshire Foundry. The foundry on Clarence Road Leeds started production in the 1930's; its closure was announced in September 2003.

West Yorkshire Foundry

The blocks were machined by Coventry Climax and returned to Jaguar for assembly. The Coventry Climax company has its roots in 1903. In 1950 Walter Hassan joined them and designed the FWA, a feather weight engine for automobiles. The first Coventry Climax racing engine appeared at the 1954 Le Mans 24 Hours in the back of a Kieft. The engine became popular in sportscar racing and it quickly became the engine to have in F2. Coventry Climax was purchased by Jaguar only one year before the quad-cam V12 project – bringing Walter Hassan to Jaguar where his talents were further exploited.

The engine logs give information on exactly how each engine was assembled as well as their detailed development history on both the test bed and when fitted to cars. The logs also refer to a number of technical reports – many of which survive in the Jaguar Heritage archive. Practically every engine component was individually coded and it is possible to trace their movements from one engine to another during development.

To be continued …..

I was privileged to be visited by Peter Wilson (ex Jaguar Competitions Department) who confirmed the identity of my prototype quad-cam V12 as being the second engine to have been built as part of Jaguar's quest to return to Le Mans with the XJ13.

Peter worked in the Competitions Department for five years up to 1966 and had hands-on involvement in the construction of the XJ13. Although a number of people have since claimed involvement in the project, many did not even set foot in the Competitions Department! - Peter is one of the few surviving members who can claim first-hand participation in the building of the XJ13 Le Mans prototype racer.

Since leaving Jaguar, he has worked in a number of prominent and senior positions in the automotive industry including time spent Brico Engineering, Cummins Diesel Engines and British Leyland. Since his retirement in 1999 he has written the definitive work on the Competitions Department between 1961 and 1966 including not only the XJ13, but a significant era in the racing and development of the E-Type. I can heartily recommend Peter's book "Cat Out of the Bag" which is available from Paul Skilleter books at http://www.paulskilleterbooks.co.uk/

Peter Wilson - Jaguar Competitions Department 1961-1966 with the second prototype quad-cam V12 engine

Peter is an engaging character with an absolute wealth of information on Jaguar. His straight-forward and no-nonsense account of people, places and the cars kept me absolutely enthralled during his visit. He is a very likeable person with a truly remarkable memory for the detail of past events.

I learnt a lot from Peter about my own engine - in particular:

• It is without doubt the second engine assembled by Jaguar as part of their "XJ6" (quad-cam Le Mans V12 engine) project
• It possesses the ultimate development of the quad-cam head (heads nos 18 & 19)
• The engine was fitted to two Mk10 (XJ5 Project) Cars for continued testing - I guess the XJ13 itself would have attracted too much attention! The engine was removed from the car in 1969 and then stored in the Experimental Department after a short time on the test-bed.
• The engine appears to have been untouched since being displayed at the Coventry Herbert Art Gallery & Museum in the early 1970s (engine still in the ownership of Jaguar).
• It is likely the engine was transferred to Jaguar (Germany) for display from where it was eventually sold to a member of the general public around 1980 (the engine was subsequently displayed at the Essen Motorshow in 1998 - see HERE
• The engine today remains in the same condition as when it was removed from the development test-bed in 1969 (albeit with an external cleanup for display! - the final tests carried out on the engine were to measure exhaust emissions - probably as a comparison with the later SOHC "Heron" V12 project)
• Although the engine has a wet sump (fitted when installed in the Mk10 project cars), it is a converted original dry sump.
• Although fitted with 6 x SU carburettors when installed in the Mk10 cars, the engine was initially assembled with Lucas mechanical fuel injection as the XJ13.

Peter is now engaged on writing an account of the XJ13 and we look forward to this latest book. There is so much myth and misinformation about the XJ13 that it will be very valuable to have an account written by someone who was "really there" and at the heart of the XJ13 project. For example, he was able to confirm that the XJ13 cam drive was always by means of duplex chain and certain changes made to the original car during its post-crash rebuild in 1972/73.

For now, Peter's last book, "Cat Out of the Bag" contains a whole chapter on the XJ13 with much previously-unpublished material.

Title

Nos.1, 3 & 7 XJ6 V12 Engines

Initial Study carried out at the Jaguar Daimler Heritage Trust, Coventry on Tuesday, 30^th March 2010

Abstract

Initial conclusions of a study of original log books and associated documentation in relation to the lineage and significant events in the history of No.1 & No.7 XJ6 V12 engines as fitted to the Jaguar XJ13 prototype car. A consideration is also given to their relationship with No.3 XJ6 V12 engine.

Main conclusions drawn at this early stage are:

1.      Prior to 1978, the XJ13 fitted prototype engines’ cam drive was exclusively by means of duplex chain – and not geared drive as previously thought. It is easy to see how this misunderstanding came about because, after the removal of the No.1 engine from the XJ13 in April 1967 (necessitated by a missed gear change), it was replaced by the No.7 engine (also duplex chain-drive). In July 1967 a gear-driven cam arrangement was added to the No.1 engine while it was out of the car (some parts, including con-rods were transferred from the No.3 engine to the No.1 engine during this rebuild). The No.7 engine remained in the car until July 1978 – sometime later, it was replaced by the No.1 engine which remains in the car to this day. There is no written evidence to suggest that the No.7 engine was ever fitted with anything other than chain-drive.

2.      Although there is an unbroken lineage of the “No.1” and “No.7” engines (thought to be the only two engines to have been installed and tested in the XJ13 – both of which are believed to accompany the car today), during the course of development, major parts such as cylinder blocks, oil pumps etc were interchanged with other prototype engines. Most notable of these was the transfer of No.1’s cylinder block (almost two years after No.1 was first assembled) and associated parts to the No.3 engine.

3.      Whilst subject to the same rigorous testing as the No.1 engine (only No.1 and No.3 log books extend to two volumes), there is no record to show that No.3 was ever fitted to a car  - certainly up to the final log book entry in March 1967 stating that the No.3 engine con-rods were removed and fitted to the No.1 engine. However, a subsequent rebuild/development of the believed "No.3" engine may have taken place as evidenced by its inclusion of (so far) undocumented cylinder heads and other prototype components – including the fitment of Jaguar Mk10/420G-compatible exhaust manifolding. Further work is needed to establish the history/development of the believed “No.3” engine after March 1967.

Introduction

A paper-based initial study was conducted by the author, Neville Swales[1], at the kind invitation of Anders Ditlev Clausager[2] of The Jaguar Daimler Heritage Trust, Coventry – and the assistance of Derek Boyce[4], carried out on Tuesday, 30^th March 2010.

Permission was granted to assist in the determination of the history, background and provenance of the “No.3” XJ6[5] V12 prototype engine currently in the ownership of Neville Swales – one of the original total of six engines. The documents provided were the original engine test-cell log books and a project internal memo[7]. Also provided w as a rather intriguing internal memo giving the go-ahead to “convert a 12 cylinder engine to a V8 engine”[8] This information was supplemented by a visual examination  of the major external components of the actual No.3 XJ6 V12 engine.

The origins of Jaguar’s V12 and desire to return to international racing is already comprehensively documented by various authors – including Peter D Wilson[9], Paul Skilleter [10] and Norman Dewis[11]. Although Peter Wilson left the Jaguar Competitions Department in the same year the XJ13 was fitted with its first prototype engine, he was involved in its early development and construction.

In 1964, the go-ahead was given to produce a series of prototype V12 engines. Later, in 1965, the go-ahead was given to build a prototype competition car, the XJ13 – with an engine “specification as set out in Mr Baily’s project specification No. ZX/558/03/1”[12].

As far as can be ascertained at present, the only engine assembled to this ultimate “competition spec” was No.7 as fitted to the XJ13 on 11^th May 1967. The log for No.7 states, “10/5/67 Removed from test bed…” and, “11/5/67 Engine handed to Mr Brookes for installation in XJ13 rear engined car”. This engine replaced the previously-installed No.1 engine (itself “assembled to project specification ZX/555/01 project schedule X127”).

It is likely that No.7 engine was fitted to the car earlier than anticipated because the installed No.1 engine suffered a catastrophic failure before the 25th^th April 1967 as this entry in its log states – “25/4/67 Engine removed from car after missed gear change and revs 8,200+ causing broken tappet on No.5 A bank. Engine dismantled for inspection.” Although conjecture at this stage, the fact that No.7 engine was assembled with chain-driven cams rather than the specified gear-driven arrangement, suggests that insufficient development time was available to fit gear camshaft drive to the No.7 engine before installation in the XJ13.

All through the logs for Nos. 1 and 7 engines, there are numerous references to chain drive of the camshafts – for example:

No.1

“ … 2/12/64 … chain dampers for top chains badly worn ..”

“ … modified upper chain dampers fitted …”

No. 7

(during assembly) “ … 12/8/65 … Timing chain brackets, chains, sprockets, dampers from No.4 XJ6 …”

The single mention of gear-driven camshaft drive occurs in the log for No.1 engine (after it was removed from the XJ13 – No.1 engine, complete with new gear-driven camshaft drive was not refitted to the XJ13 until after July 1978)

No.1

“ … 12/5/67 … installed on No.8 test bed …”

“ … 26/6/67 … cylinder heads removed, stored in EXP …”

“ … 4/7/67 … timing gear to X134 specification to suit gear driven camshafts .100” eccentric intermediate shafts fitted …”

A greatly-simplified overview of the relationship between engines 1,7 and 3 is shown below:

Future Work

After March 1967 there are no further entries in the log for engine No.3. Further investigative work is required.

A detailed analysis of the engine logs for the remaining three engines (Nos 2, 4 and 8) has yet to be carried out. It is anticipated that there may be references to No.3 engine contained therein – particularly in the case of No.2 engine which contributed many parts to No.3.

Although many Jaguar ex-staff who were intimately involved in the project are no longer with us, some do remain and it is hoped to gradually build up a picture of events surrounding the project between the years 1964 and 1978. The JDHT archive is, thankfully, very well organised and managed now and it is possible that further, previously thought to be unrelated, documents may come to light.

Once a fuller history of the engine is determined, an appropriate and suitable use of it will follow. No.3 is clearly an important engine – at the heart of Jaguar’s initial attempts to design an engine that would not only power a Le Mans winner but evolve into a refined and world-beating production car engine.

Acknowledgements

I wish to record my appreciation of the friendly and open assistance given by The Jaguar Daimler Heritage Trust – in particular Anders Clausager (Chief Archivist), Derek Boyce (Volunteer Archivist), Richard Mason (Vehicle Engineer – and intimately involved with the XJ13 during its recent rebuilds) and Karam Ram (Picture Archivist).

As a long-standing Jaguar enthusiast, this is a very special and exciting project for me and I also wish to thank those many similarly-afflicted enthusiasts who have helped with their support and guidance so far – people such as Trevor Williams (TWRR), Tim Nevinson (Author and ex-Jaguar Apprentice), Paul Skilleter (renowned author), Roger Kemp (Jaguar Drivers Club), Tony Griffiths, Steve Myciunka (who shared 24 hours driving with me to repatriate No.3 engine from Germany), Tony Brown (Jaguar World), Martin Emmison (Lawyer) – and many others including posters on Autosport, Pistonheads & JagLovers internet forums.

The following pictures (many more to follow ...) show some of the external details and initial findings of the prototype V12.

The engine is in superb condition - testament to its dry storage conditions by its previous owner for the last 30 years.

Collection from resting place in Germany for the past 30 years - before almost non-stop 12 hour drive back to the UK! Customs officials were taken aback by what initially seemed to be a V12 mid-engined pickup ...

After leaving Coventry, the engine passed to Jaguar (Germany) who sold the engine to the previous owner. The previous owner displayed the engine at a Motorshow in Essen, Germany in 1998 in the same condition as when it left Jaguar (although he said he polished it!). There is a mention of the engine at Essen, as well as a picture of it, at http://www.stallard-engineering.co.uk/stories/Jaguar/ESSEN.htm

It seems the engine may have been rebuilt/restored in England by Jaguar before it was transferred to Jaguar (Germany).

The engine turns easily and looks to be complete internally. Looking into the inlet shows slight carbon buildup around the inlet valve so it was possibly run for a while before it was put into storage by Jaguar.

The cams are chain-driven although there is evidence of considerable modification in this area. It is possible there was a different cam drive mechanism at some point and it was later converted to chain drive. Interestingly, there is an external chain tensioning mechanism as can be seen in the following picture. The large nut can be used to exert pressure on the chain via a "slipper".

Device for tensioning cam chain drive.

All the currently accessible major parts have "X" (for experimental) identifying numbers and many are also complemented by hand-stamped numbers - mostly the number "3". I suspect these numbers will be recorded somewhere in Jaguar's archives and I hope to be able to access them at some point. I list some of the numbers below in the hope they may mean something to a fellow-enthusiast.

1. Front of sump - IXW 5041 (cast)
2. Front of block below water pump casing - remains of a number that could start with "X" and end with "015" (cast) (there is a stud through the middle of the number!)
3. Water pump casing - 0XW 5020 (cast)
4. Rear of flywheel - 2XW 5179 (stamped)
5. Front of block (below water pump housing) - stamped number "3"
6. Front of left head - stamped number "19"
7. Rear of left head - WM70253 0XW5641 (cast) and "T3" stamped twice
8. Front of right head - stamped number "18"
9. Rear of right head - WM70252 0XW5640 (cast) and "T3" stamped twice
10. Cams are engraved with "X" numbers / timing etc.
11. Jackshaft (distributor drive) cover - 2XW 5043 and stamped number "3"
12. Centre distributor (cylinders 7-12) - LT22357, crossed-out number below, then X2 66 (all stamped)

This engine has two 6-cylinder distributors. The plug leads are all individually numbered and it seems the centre distributor connected to cylinders 7-12. The distributors appears to be development versions and there is provision for some sort of linkage (missing) to simultaneously alter their timing. Rather perplexingly (for me anyway!), only one of the distributors has a vacuum advance mechanism - with no evidence that the other distributor has ever had vacuum advance.

Removing the right-hand bank exhaust cam cover shows it to be a substantial alloy item which is thicker than production XK cam covers. The cam bearing caps appear to be hand-finished and shaped and are all individually numbered with corresponding marks on the head. The cams themselves appear to be reground cams with quite an aggressive profile. Each cam is engraved with its experimental "X" reference number along with other numbers which may be timings. Although only a superficial examination at this stage, things such as clearances will be measured before the cams are removed.

(Exhaust headers are custom welded tube and not cast iron as in production cars).

Although a detailed examination of the sump will follow, externally there is evidence of considerable modification.

This picture also shows the rear suspension/engine mounting bracket casting. The XJ13 uses the engine as a stressed member as later practised by Lotus - this same mounting point could be used to mount the engine when fitted to a road car "mule".

The spark plugs are in the most inaccessible location! It must have been a nightmare to change them when the inlet manifolds were in place ....

More pictures to follow ......

I have been fortunate enough to acquire one of the original Jaguar V12 Prototype V12 engines. Over the next few weeks I shall post details here of this engine - its history and construction. 

I believe that this is one of only four surviving engines from the original seven prototypes. However, I have yet to definitely confirm numbers etc. Current wisdom says that there are four engines remaining - two with Jaguar in Coventry (one of which is fitted to their restored XJ13), one in a Wingfield XJ13 replica originally built for Walter Hill in the US, and my engine.

I have yet to determine the precise history of my engine - I feel a visit to the Jaguar-Daimler Archive coming on!

For now, here are some pictures of the engine "as found" - note the provision for a Mark 1 Lucas metering/distribution fuel injection unit (driven by the small cam shown adjacent to one of the distributors). I am also led to understand that, although it has two 6-cylinder distributors, these were not originally fitted to this engine (note the different caps). It is possible that a 12-cylinder distributor originally took the place of the current "centre" 6-cylinder distributor. I have yet to examine the cam drive arrangement but expect to find either all-chain or a combination of chain (from the crank) and gears (driving the individual cams from this single chain). I will post a photographic record as the examination continues.

Here are some pictures showing how a home-made device can be used to easily separate V12 heads from the block.

Having studied Kirby Palm's excellent technical summary of the V12 (downloadable for FREE from http://www.jag-lovers.org/xj-s/book/XJS_help.pdf), and having listened to some tales of woe from others who have struggled vainly to separate the heads from the block, I decided it would be well-worthwhile making up a device to simplify head removal - particularly as I have at least two engines to rebuild. Also, when I went to collect this engine, I was shown a block where one head had been completely removed and the second was stuck fast - even though there was 3 inches of fresh air between the head and the block. The owner had tried over many months to separate the second head (without the benefit of "The Beast" but all attempts had failed. He was even considering having a hollow reamer made that he could slip around each stud - but I suspect this is "clutching at straws". Perhaps, if I am feeling generous, I may pay him a visit with "The Beast" in tow.

I have probably spent more time making up such a device than actually working on the engine, I feel it was time well-spent! I have christened the head-removal device "The Beast" because of its size and weight :)

I must add here that I have become an avid reader of the V12 forum on the "Jag-Lovers" website. Over the last few weeks I have learnt much about the V12 from its contributors - many of whom are very experienced in Jaguars in general and the V12 in particular. I unhesitatingly recommend you subscribe to this forum if you are contemplating a V12 rebuild - the members there are invariably helpful and willing to pass on the benefit of their experience. You can visit Jag Lovers by clicking HERE.

The engine

The "flat-head" V12 in the photos had been stored in various garages/lock-ups for the past 20 years or so. I was told it was removed from a XJ12 saloon. Because of its history, I was anticipating difficulty in persuading the heads to leave the block .... The first thing to greet me when I came to remove the head nuts was just how many there are! Having been used to the relative simplicity of the XK 6-cylinder iron block, it seems I will have to develop the patience that is needed for "12 of everything" .. or should that read "24++ of everything"? Of course, it is important to remember to remove ALL the nuts holding the head down - including the ones attaching the head to the top of the timing-case. "The Beast" is more than capable of pulling a stud out of an alloy head if a nut is left attached.

Incidentally, I discovered that there is no need to make up a special tool to hold the camshaft sprockets in place during head removal if you happen to have a couple of suitable external circlips. I found that by placing circlips into the grooves already machined into the end of the sprocket spindles, the spindles can simply be dropped over their respective retainers. There is also no need to slacken the chain using special tools if you simply fasten one of the sprockets to its holder so it remains out of the way while the head is removed.

"The Beast"

"The Beast" is fabricated from two sturdy 3/4" steel plates. The top plate fits over a series of threaded bars that are welded into the bottom plate.

Step One - attach lower plate.

Place the lower plate on the head so that the camshaft locating studs protrude through it. It can then be fastened down using the original nuts and washers. Please bear in mind that this is an alloy head and do not over-tighten these nuts!

As can be seen in the next photo, the studs at the front of the engine are in different places left to right. I don't know if this is a peculiarity of all these V12 engines? The plate covers all the camshaft studs on the left-hand head, but misses the front pair on the right-hand head. If I was to make another bottom-plate, I would add extra length and holes to accommodate this left-to-right difference..

Step Two - add steel rods

Drop the rods (I used stainless) through the bottom plate so that each rests on a cylinder head stud. The diameter of the rods is slightly smaller than the cylinder head studs and they are chamfered to facilitate them following the studs through the head.

Step Three - place upper plate

Place the upper plate over the threaded bars and, using the small socket-head screws, level it making sure all the stainless rods are in contact at both ends.

Step Four - fasten upper plate

Check the plates are parallel to each other and fasten using long nuts/washers on the threaded bars.

Step Five - remove the head.

Remove the head by tightening each double-nut the same number of turns, in rotation around the upper plate. The whole operation took under an hour for each head and required very little effort - in fact, it was quite therapeutic and satisfying to see the head gradually slide up past the studs. The hardest part (once the head was lifted almost clear of the studs) was lifting the head complete with "The Beast" off the engine.

I could be persuaded to loan "The Beast" out when I am finished with it in return for a small donation towards its fabrication costs.