Introducing the tera®

Building The Legend, XJ13, Neville Swales, Jaguar, LM69, Ecurie Cars

Introducing the tera®, Building The Legend Limited’s own unique quad-cam V12 engine. The type of power unit which could have been heard howling down the Mulsanne Straight at Le Mans in 1966 and beyond.


A beautifully sculptural engine and unashamedly “of the period”. Designed to be seen and with a purposeful beauty hinting at the power lying within.

The tera® draws inspiration from Claude Baily’s (former Chief Designer, Jaguar) legendary quad-cam racing engine – an engine designed to return the company to its glory days of Le Mans triumphs and domination.

Building The Legend, XJ13, Neville Swales, Jaguar, LM69, Ecurie Cars
Introducing the tera-™, Building The Legend Limited’s own unique quad-cam V12 engine

Sadly, the one-off car was destined to never turn a wheel in anger and the potential of Baily’s mighty power-unit was never fully realised. Instead, the company re-designed Baily’s racing engine into a SOHC version more suited to sedate applications.

In the words of Walter “Wally” Hassan …

“… Between 1949 and 1957 Jaguar were actively involved in motor racing in order to create the sporting image for their cars. Amongst their successes were the winning of the Le Mans 24 Hour Race in the years of 1951, 1953, 1955, 1956 & 1957 as well as Sebring and many other international races and rallies. These cars were powered by the six-cylinder XK twin-cam engine and it was thought to be desirable to develop a successor to compete in future races, particularly Le Mans …. in order to provide the maximum potential in power, a 12 cylinder ‘Vee’ configuration … was conceived to provide for safe running at 8000-8500 rpm. By way of comparison the 6 cylinder twin cam XK engine had been designed without racing in mind.

… during the development period it was decided to withdraw from racing and these policy changes eliminated the need for a competition engine and emphasis shifted to the production (SOHC) version.”

tera®

Drawing inspiration from Baily’s V12 and other classic racing engines of the period, Building The Legend’s tera ® represents an evolution of Baily’s concept. A “what might have been”. An engine born to race but whose potential was never fully realised – until now …

The engine is of course normally-aspirated and drivers of these cars will gain the full visceral experience of a howling V12 race-engine. Distributor-less with choice of period Lucas Mechanical or Electronic Fuel injection. Safe running rev-limit of 8,000 to 8,500 rpm. Available from street-spec to full-race. Applications of this engine are limited only by your imagination!

Building the Legend can upgrade your Classic Jaguar! From a “refresh”, engine-swap, full-restoration and everything in between.

Engine Specifications:

  • Capacity:         6.1 L (372 cu in); 6.8 L (415 cu in)
  • Bore x Stroke:  96 x 70 mm (3.8” x 2.8”); 96 x 78.5 mm (3.8” x 3.1”)
  • Power:             350 – 650 hp   (261 – 485 kW)
  • Torque:            300 – 600 lb ft (407 – 813 Nm)
  • Compression:  12.7:1
  • 2-valve, over-square architecture, duplex-chain-driven cams with convenient Vernier adjustment.

Contact details:

For details of pricing, specifications, applications and delivery, please contact:

Neville Swales

Building the Legend

Telephone:      +44791 644 5253

Email:              neville@buildingthelegend.co.uk

Transform your Classic

tera®

“to the power of 12”

from the Greek – “teras” = monster.

Contact us for details https://buildingthelegend.co.uk/make-contact

Looking back to 2015

Building The Legend, XJ13, Neville Swales, Jaguar, LM69, Ecurie Cars

The year is now 2015 and my car is approaching its “rolling chassis” stage – mirroring events of 50 years ago in Jaguar’s Competition Department. It was then 1965 and William Heynes, Jaguar’s Engineering Director still had hopes of seeing the car on track to contest that year’s Le Mans endurance race. Time was short but the skilled team working behind closed doors were used to working to such tight deadlines …

Jaguar XJ12 - Building The Legend
Jaguar XJ12 - Building The Legend
Jaguar XJ12 - Building The Legend
Jaguar XJ12 - Building The Legend

Let us go back a few years …

1963.

William (“Bill”) Heynes, Jaguar’s Engineering Director takes note of a change to the Le Mans regulations which now open the door to sports/racing prototypes of up to 5.0 litres (305 cu in) in capacity. No doubt, he smiled to himself as he was now in a position to bring a plan he had long kept in the back of his mind to the fore …

Jaguar XJ12 - Building The Legend - William Heynes
William Heynes of Jaguar

For Bill Heynes, racing engines had always been in his blood. Having left Humber in 1935 where he completed his engineering apprenticeship, Heynes joined William Lyons at SS Cars. Six months later he was working closely with and became one of the prime architects of an overhead-valve conversion for the Standard 6-cylinder engine. The first cars to have this engine installed were known as SS Jaguars. One of these first cars was the SS Jaguar 100. The power unit Heynes had a hand in designing soon powered this car to best performance in the 1936 Alpine Trial – showing these cars were more than just pretty faces.

Ten years later, Bill Heynes combined his talents with Harry Weslake, Walter Hassan and Claude Baily to produce Jaguar’s legendary and long-lived 6-cylinder XK engine – an engine which was to bring Jaguar success, not only in the showroom, but also in the highest-level of competition. Cars powered by these engines still dominate fields in historic racing today. After successes in the 1950s at La Sarthe with the works C-Types and D-Types, Jaguar switched their efforts to road cars and formally retired from racing in 1956 (although the factory continued to support private entrants).

Jaguar XJ12 - Building The Legend
Left to right: Walter Hassan, William Heynes and Claud Baily of Jaguar

Heynes did not disband Jaguar’s Competition Department and ensured its personnel remained intact after 1956. Key amongst these personnel were Malcolm Sayer who had masterminded the design of the highly-successful C-Type, D-Type and the E-Type prototypes. Another member of this select team was the South African Derrick Whyte, a talented chassis engineer who had cut his teeth at Connaught and became associated with their well-engineered, beautifully-built and superbly-handling cars. The third member of the team was Alex Frick whose expertise lay in tubular chassis frame design.

By 1963 Jaguar were on the brink of a return to racing with their Lightweight E-Types. However, the change in regulations for Le Mans in 1963 meant these beautiful cars would have been completely overwhelmed by the 5-litre prototypes now allowed by the regulations. The way was clear for Bill Heynes to carry out his plan for a full assault at Le Mans with a new mid-engined prototype sports car powered by Jaguar’s own 5-litre quad-cam V12 – an engine which was first and foremost aimed at racing with a possible secondary use in one of Jaguar’s future road cars. Unlike the XK 6-cylinder engine which was aimed fairly and squarely at road use and later modified for racing.

On 9th July 1965, Heynes despatched a young Mike Kimberley to Silverstone to see what he could learn. His brief? To brush up on the latest in Sports Racing Car design to see what the others were doing.

Fast-forward …..

The story and fate of Jaguar’s car designed to carry out this assault at Le Mans is now well-known.

In short …

Only one car was built and circumstances conspired to prevent the car from ever turning a wheel in anger. Construction began in 1965 and the sole example built was completed in 1966. Its breaking of the UK closed-lap circuit record in 1967 in the hands of its main Test & Development Driver David Hobbs, showed its potential. This record was to stand until 1999 until beaten by a McLaren F1 road car.

Many myths and stories have been built up around this legendary car over the years. In recent years, exhaustive and comprehensive research by respected author Peter Wilson has established the facts surrounding this car – research which has been substantiated by interviews of those who were there as well as a mass of surviving contemporary documents and reports. Peter’s book “XJ13 – The definitive story of the Jaguar Le Mans car and the engine that powered it” provides a definitive record and builds on earlier writings from Jaguar historians such as Andrew WhytePaul SkilleterBernard ViartMichael Cognet and Philip Porter.

The car underwent a series of clandestine but official tests arranged by its Project Manager Mike Kimberley (later to become CEO of Lotus Cars). Professional race-driver David Hobbs piloted the car in all official tests, supported by Norman Dewis and Richard Attwood. The one-and-only original was put under wraps in 1967 where it remained until 1971 when it was wheeled out to help publicise the forthcoming Series 3 V12 E-Type. The sad fate of the car in the hands of Norman Dewis is now well-documented. The car was crashed and its mostly-intact underlying structure was clothed in a new body fashioned by skilled craftsmen at Abbey Panels.

The sublimely beautiful lines of Sayer’s masterpiece were altered during the rebuild and the car remains in this altered form to this day. Regularly displayed at prestigious events the car forms a backdrop to Jaguar’s rich heritage and testament to the genius of Malcolm Sayer.

Many replicas of Jaguar’s current car exist although none have yet come close to capturing Sayer’s original 1966 form. Jaguar’s one-and-only altered original was digitally scanned recently and the resultant body is being applied to a GT40-inspired chassis which contains parts of an engine which, although never installed in a car in period, does contain surviving original prototype quad-cam components. This car, however, replicates the car as it stands today with its many differences to the 1966 original.

In 2010, I acquired the only surviving complete original prototype quad-cam V12 built to a specification similar to that of the engine which powered the original car in 1966. Four years of exhaustive and painstaking research have resulted in the accumulation of original and unique data for Jaguar’s original 1966 masterpiece.

What to do with this engine and all this data?

What would YOU do?

CONSTRUCTION BEGINS

First of all, the following must be emphasised:

There is, and always has been, one Jaguar XJ13. The car is owned by the Jaguar Daimler Heritage Trust. Undoubtedly, their car is unique and has continuous history linking it back to the one and only original. It may have been described as a, Jaguar-built replicaby authors Viart & Cognet in their 1985 book, “Jaguar – A Tradition of Sports Cars” (page 318), with forward by William Lyons himself, but this may be a little unfair as most of the underlying structure was salvaged and re-used. The engine installed in the car today is a different engine to the one originally installed in the XJ13 in the Spring of 1966 but it remains one of the very few prototype quad-cam engines that have survived and was installed in the car in period. OK, the body may be completely new, and different in some respects to the original body, but there can be no doubt that the car gracing the Jaguar Heritage collection can describe itself as the unique Jaguar XJ13.

There may be no copyright subsisting in the XJ13 but what Neville is attempting to create can only ever be a facsimile and homage to the original XJ13 and its designer Malcolm Sayer. There is, and always has been, ONE Jaguar XJ13.

The prospect of actually driving the car under its own power for the first time is something which keeps me awake at night … 🙂

My aim, from the outset, was to attempt to replicate not only the original car but also to follow the build sequence as carried out by Jaguar in their Competition Department. As time went on, both myself and the people entrusted with the build of his recreation came to respect the skills of the original builders more and more. Without doubt, today’s use of computers and rapid-prototyping does make life easier. Wheras I was able to digitally model and “trial-fit” virtual components and body panels on a computer screen, these techniques weren’t available in 1964 and the builders of the original made do with “trial and error” as well as experience born from years of mastery of their craft.

In September of 1964, although there had been no official “go-ahead”, Bob Blake assisted by Geoff Joyce andRoger Shelbourne set about translating Malcolm Sayer’s hand-written data into wooden “buck” which could be used to shape the outer body skin.

Jaguar XJ12 - Building The Legend
Photo taken during the crashed car’s rebuild in 1972/73 showing the original rear body buck in the foreground.

The bucks (two in total – front and rear) were to be sent to Abbey Panels who would form the outer skins leaving Jaguar to fabricate the car’s monocoque/chassis. All they needed now was the formal go-ahead.

I followed a similar process – translating 3D data (and data derived from original technical drawings and photographs) into a “virtual” wooden buck which could be used to shape the outer body skin of my recreation. I was assisted in this process by CAD/3D specialists. Considerable work was needed by the skilled team at my chosen bodyshop to remedy shortcomings in the supplied buck and to ensure faithfulness to the original car but we eventually ended up with something which could be used in the real world! To ensure accurate replication of details such as headlamp apertures, air scoops and windscreen surround, parts of the wooden buck had incorporated solid 3D sections which would be used as “hammer formers”. At this stage, the wooden buck only existed on a computer screen.


©Neville Swales – Digital representation of full-size body buck (third-scale model in foreground). Looks “pretty” but this is only a digital representation needing considerable work by skilled artisans for its use in “the real world”.
©Neville Swales – Close-up of actual buck.
©Neville Swales – Hammer-form nose-cone and headlamp 3D sections.
©Neville Swales – Nose-cone 3D section being CNC machined

Before this virtual buck was turned into reality, I digitally replicated the XJ13’s underlying chassis/monocoque and was able to virtually “trial fit” the body onto it to ensure everything was as it should be.

©Neville Swales – Trial-fitting virtual components
©Neville Swales – Trial-fitting virtual components

I was also able to add suspension components, engine, wheels and tyres etc to ensure everything would fit together without fouling when the digital model became reality. At this stage, it was possible to view the model from every possible angle as well as estimate things like final weight distribution, centre of gravity and the way light would catch the finished body surfaces. These are all things unavailable to Jaguar in 1964 and, instead, would have relied on trial-and-error as well as pure skill. The original builders were truly craftsmen.

Something which certainly wasn’t available to Jaguar in 1964 was the ability to print small-scale 3D models of the body before committing to buck manufacture. It is all very well being able to see things on a computer screen but being a bit “old school”, I didn’t feel comfortable giving the go-ahead to manufacture a full-size buck until I had something I could hold in my hand. Something which could be held and, in theory, be painted so the way it caught the light could be studied. I therefore commissioned a number of small-scale 3D-printed models to give himself greater confidence in the accuracy of the final body. 1/3rd and 1/6th bucks were also produced to show details which may not have been apparent at a smaller scale. These small-scale models did show some shortcomings in the digital data arrived at by my chosen 3D specialist and some manipulation of the data was required to arrive at something more satisfactory. I do recommend the use of 3D-printed models if you are considering taking the same path because things which can look “pretty” on the screen do not always translate ideally into “the real world”. It always helps to have something you can hold in your hand!

Finally, reasonably satisfied with the accuracy of the model, I gave the go-ahead for a full-size buck to be made directly from the CAD data – knowing that it could only represent a “guide” and the skills of the bodyshop would overcome any shortcomings. My faith in the skills of my chosen bodyshop proved to be well-founded.

Meanwhile, back at Jaguar, there was still no formal “go ahead” for the outer body skin to be made by Abbey Panels. The Competition Department staff knew that, if the car was going to be ready for the 1965 Le Mans, they really needed to get on with it. Derrick White pressed Bill Heynes but was told “not yet”. First signs of a lack of urgency around the project were becoming evident. Sadly, knowing what we do now, the best chance of a win at Le Mans would have been in 1965 – before Ford’s GT40 had got into its stride leaving Ferrari as the only serious competition.

As Peter Wilson reports in his book, “XJ13 – The definitive story of the Jaguar Le Mans car and the engine that powered it”,

“… as the surface plate we had in the Competition Department was not large enough, or indeed remotely suitable, Bob Blake, Geoff and Roger constructed a very rigid wooden platform on which to build the monocoque. This consisted of a cross-braced perimeter frame constructed from 9 x 3” timber, topped with ¾ inch thick plywood sheet. It was marked out with ’10 lines’ – lines 10 inches apart, either side of the longitudinal centreline, along the length of the platformand similarly in the transverse direction, from the front ‘zero’ datum point (the centreline of the front wheels). This would enable accurate referencing of each of the myriad of construction reference points defined by Malcom Sayer’s drawings.”

As a further means of ensuring accuracy of the replica monocoque, I turned to his computer again and commissioned a “monocoque buck” based on these reference points which would be precisely located in relation to the ’10 lines’. The originally supplied monocoque buck proved not to be fit for purpose and I commissioned a further buck to ensure faithfulness to the original.

©Neville Swales – Monocoque buck showing ’10 lines’ on baseboard

My chosen bodybuilders, used this monocoque buck to fabricate and build the front and rear suspension sections. We designed his own jigs to precisely locate all suspension components consistent with Jaguar’s original data.

Back in the January of 1965, Bob Blake made a start on the monocoque. At the time, it was believed that it was still possible to have the car up and running in time for Le Mans – although time was very, very tight. The hard-working members of the Competition Department were used to these tight deadlines. For example, work had started on the E2A E-Type Prototype in January of 1960. It was ready to run before the end of February and went on to race at Le Mans in June of the same year.

An XJ13 at the 1965 Le Mans was still a possibility.

The monocoque centre section consisted of the floor and outer sills. These were produced in two halves, as mirror-images of each other and joined along the centreline of the car using a double row of 3/16” dome-headed rivets. The sills had internal stiffeners and were roller-welded along their lengths. The Competition Department didn’t possess equipment to do this themselves so the entire assembly was shipped to Abbey Panels so they could be welded there. The welded sill sections were returned to Jaguar where bulkheads and door apertures were added. The team had been added to by that time by Denys Davies who assisted Derrick White with fabrication of detailed suspension components.

©Neville Swales – Original rear monocoque construction detail
©Jaguar Heritage – Original front monocoque construction detail (reproduced with permission)
©Neville Swales – 2013 vs 1965

Determined to exactly replicate the XJ13 monocoque, we decided to fabricate a “prototype” sill structure in steel just “to get it right” before we fabricated the final version using the (rather expensive) original-spec aluminium.

©Neville Swales – Prototype all-steel monocoque on the originally-supplied monocoque buck (later to be replaced by a more accurate and usable item).
©Neville Swales – Prototype all-steel monocoque
©Neville Swales – Trial-fitting of front suspension on steel prototype monocoque
©Neville Swales – Prototype front suspension on steel prototype monocoque
©Neville Swales – Final monocoque – front suspension detail (NB original XJ13 does not have collapsible steering column section)

This steel prototype has since been destroyed and its place taken by the final aluminium version. As with the original, the front suspension consists of a steel framework riveted to the floor and front bulkhead. After many iterations and failed attempts by Derrick White to persuade Bill Heynes to use a state-of-the-art purpose-designed front suspension setup, Heynes prevailed and the XJ13 was fitted with a modified 1964 Lightweight E-Type front suspension as can be seen in the following picture:

©Jaguar Heritage – Front suspension detail – as 1964 Lightweight E-Type (reproduced with permission)

I replicated the front suspension as far as I was able to arrive at the following:

©Neville Swales – Final monocoque – front suspension detail

The words Jaguar, Jaguar XJ13, XJ13 are used in a historical/descriptive context and in no way suggest our recreations/replicas are approved by Jaguar. It is widely known that there was only ever one Jaguar XJ13 and any others can only ever be replicas, facsimilies, tributes, recreations, toolroom copies or similar.

Jaguar XJ13 – Malcolm Sayer’s Crowning Glory

Building The Legend Limited

“Sayer uniquely blended science and art to produce timeless shapes of exceptional and enduring beauty. He brought science to the art of car design; and scientifically produced works of art.”


21st May 2016 marked the Centenary of the birth of one of this country’s greatest design geniuses. Malcolm Sayer was taken away from us at a relatively young age when he suffered a fatal heart attack, outside Parkside Garage, next to the Regent Hotel in Royal Leamington Spa, 1 month before his 54th birthday.

His legacy is a collection of iconic Jaguar Sports Cars – C-Type, D-Type, E-Type and the sublime XJ13 – the latter being his crowning achievement.

1966 to 2016 – 50 Years

Coinciding with his birthday, the first public “reveal” of my recreation of Sayer’s 1966 XJ13 took place at the London Classic Car Show at the Excel in London. The car is my personal tribute to this great, and perhaps under-appreciated, man whose final resting-place is unknown – even today.

The car replicates Jaguar’s XJ13 as it first left Jaguar’s Competition Department – as Malcolm Sayer envisaged it and before it was crashed and re-skinned in 1972/73.

At the end of 2014, the bark of Jaguar’s legendary No.2 quad-cam V12 engine was heard for the first time in 50 years. The starter was pressed by the same Jim Eastick who started the No.1 engine for the first time in 1964 in the presence of Jaguar’s Bill Heynes – this time, in the presence of Jonathan Heynes, son of the late Bill Heynes.

1916 to 2016 -100 Years

Just over 100 years ago, Gilbert and Annie Sayer became parents to a son they named Malcolm. Malcolm Sayer – a name which was to become synonymous with Jaguar’s classic and most beautiful iconic designs. Malcolm’s birth in 1916 no doubt represented a bright spot in the otherwise dark times during the middle of the First World War in that eastern corner of the UK – Cromer, Norfolk. Malcolm’s father, Gilbert, was a teacher at Great Yarmouth Grammar School where he taught the unusual combination of Maths and Art – certainly a man whose interests would have influenced the direction his son’s career was eventually to take.

Malcolm’s birth, preceded by a German Zeppelin attack on the Eastern Coast of the England, coincided with the introduction of UK Daylight Saving on the 21st May 1916. Cars were relatively few and far between on Norfolk roads with most being made by the Ford, Rover, Wolseley, Morris and Humber car companies. Smaller-volume manufacturers such as Crossley also had offerings. The kind of cars on Britain’s roads around the time the infant took his first steps were similar to those pictured below – a far cry from the designs later to emerge from his pen!

EarlyDays

Malcolm’s Grandson, Sam (Founder of The Malcolm Sayer Foundation) takes up the story:

“From the start he was interested in maths art and science, and despite many childhood illnesses, he was a high academic achiever and gained the prestigious Empire Scholarship* at the early age of 17. This enabled him to attend the then Loughborough College, where he gained a first class honours diploma in Automotive Engineering. He was also Secretary of the College motor Club and for two years Editor of the College Magazine.

After graduation, Malcolm joined the Bristol Aeroplane Company, studying aeronautics and looking at ways of improving the efficiency and design of significant WW2 aircraft, particularly the Blenheim and the Beaufighter; and developing his expertise in aerodynamics as applied to mechanical design. Following the war he married Pat Morgan in 1947 and after his daughter Kate was born in 1948 he went to Iraq to work at Baghdad University. This turned out to only exist on paper, so he worked instead maintaining the fleet of government vehicles.”

*The “Empire Scholarship” referred to above were open to all British subjects living in any part of the Empire. These scholarships awarded the sum of £75 per annum which helped Malcolm complete his studies at the Faculty of Engineering at Loughborough College.

The pictures below show students working using Loughborough College’s wind tunnel during Malcolm Sayer’s years (pictures reproduced with permission from Loughborough University): 

Wind Tunnel – c1936 © Loughborough University
Wind Tunnel – c1936 © Loughborough University
Wind Tunnel – c1936 © Loughborough University

Malcolm Sayer – Aerodynamic Wizard

A few years ago the BBC recorded a tribute to Malcolm Sayer. The program was aired on Radio 4 and presented by Jonathan Glancey. Contributors included Sir Stirling Moss, Lord March of Goodwood, Philip Porter, Peter Wilson, Kate Sayer (Malcolm’s daughter), Jools Holland, Norman Dewis, Mike Kimberley, Mick Walsh and Yours Truly. The following video adds pictures to the radio broadcast:

Bristols

Malcolm Sayer graduated from Loughborough College and joined the Bristol Aeroplane Company on the 22nd September 1938.

According to our friends at Wikipedia …

“The Bristol Aeroplane Company, originally the British and Colonial Aeroplane Company, was both one of the first and one of the most important British aviation companies, designing and manufacturing both airframes and aero engines. Notable aircraft produced by the company include the ‘Boxkite’, the Bristol Fighter, the Bulldog, the Blenheim, the Beaufighter, and the Britannia, and much of the preliminary work which led to the Concorde was carried out by the company.”

A few years later there was to be a tenuous link between Malcolm and Jaguar as Norman Dewis OBE was to fly as gunner in Bristol Blenheims. I wonder if Norman and Malcolm ever discussed this when they met up at Jaguar years later?

The Mysterious German

Sayer, by virtue of having a “reserved occupation” at the Bristol Aeroplane Company, was spared National Service during WW2. Instead, he put his skills to good use helping design warplanes and their engines for the Allied war effort. He married Patricia at the end of hostilities. Patricia gave birth to their first daughter, Kate, in 1948. I am sure Kate won’t thank me for mentioning the date … 😉 Malcolm and Patricia later extended their family with another daughter (Mary – 1956) and a son (John – 1953).

Kate Sayer
Malcolm’s First Daughter

In the same year as Kate was born, Malcolm was asked to establish a Faculty of Engineering at Baghdad University. He duly arrived in Iraq only to find the opportunity to create the Faculty didn’t exist! His time wasn’t wasted however and he instead spent a few days alone in the desert by a German Mathematician. he was later joined in Iraq by his wife and new daughter.

Malcolm learnt from the mysterious German and used his teachings to develop his own unique way of defining complex shapes in a purely mathematical way – much as we do nowadays using CAD and computers. He always kept the details of exactly how he did this very close to his chest.

Ex-Jaguar Competition Department and Author Peter Wilson described Sayer’s way of working as follows in his book, “Cat Out of the Bag” (no longer in print):

“Malcolm’s drawings contained no lines per se, but consisted of a matrix of dimensional points defined in three planes from a common base reference point, which defined the outer surface of the skin panel. His method was unique in the motor industry, but more commonplace in the aircraft design world. Malcolm claimed he had been taught this mathematical method of complex curved surface definition by a German, when they spent a few days together in a tent in the desert ….

… It was a system which was relatively easy to use: just a case of marking out the points defined by the coordinates on a sheet of plywood, cutting it out, then assembling each piece relative to its datum on a wooden base and ‘hey presto’, you had a complete skin former …

… Malcolm kept his method of mathematically calculating complex curved surfaces very close to his chest …”

A Legacy

Malcolm Sayer has left us with some of the most beautiful examples of sporting automotive design the world has seen.

Even today, at Jaguar, the essential elements of his designs can be seen in cars such as the C-X75. Jaguar’s concept (which may see production) unashamedly draws on its styling cues from Sayer’s XJ13. Check out the following pictures and video:

© Building The Legend 2016
© Building The Legend 2016
© Building The Legend 2016
© Building The Legend 2016
© Building The Legend 2016
© Building The Legend 2016

The words Jaguar, Jaguar XJ13, XJ13 are used in a historical/descriptive context and in no way suggest our recreations/replicas are approved by Jaguar. It is widely known that there was only ever one Jaguar XJ13 and any others can only ever be replicas, facsimilies, tributes, recreations, toolroom copies or similar.

“The Gathering”

Looking back on a very special gathering a few years ago.

A big part of the project for me is the opportunity it gives me to spend time with the skilled engineers who worked on these cars in the 1960s and earlier. “Backroom Boys” without whom Jaguar would not have enjoyed the success it achieved.

Thank you gentlemen 👍

Looking back on a very special gathering a few years ago. A big part of the project for me is the opportunity it gives me to spend time with the skilled engineers who worked on these cars in the 1960s and earlier. "Backroom Boys" without whom Jaguar would not have enjoyed the success it achieved.Thank you gentlemen 👍

Gepostet von Neville Swales am Dienstag, 26. November 2019

The words Jaguar, Jaguar XJ13, XJ13 are used in a historical/descriptive context and in no way suggest our recreations/replicas are approved by Jaguar. It is widely known that there was only ever one Jaguar XJ13 and any others can only ever be replicas, facsimilies, tributes, recreations, toolroom copies or similar.

How many quad-cam V12s were built and where are they now?

XJ13 Original Quad-Cam V12

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.

XJ13 - Building the Legend
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.

XJ13 - Building the Legend
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.

XJ13 - Building the Legend
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.

XJ13 - Building the Legend
3.5 litre experimental XK engine – drawing produced to calculate compression ration.
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XJ13 - Building the Legend

Left to right – Walter Hassan, William Heynes, Claude Baily.
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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.

XJ13 - Building the Legend
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 …”

XJ13 - Building the Legend

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XJ13 - Building the Legend
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XJ13 - Building the Legend
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XJ13 - Building the Legend


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XJ13 - Building the Legend
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XJ13 - Building the Legend
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XJ13 - Building the Legend
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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.

XJ13 - Building the Legend
Baily’s drawings showing his ideas for a quad-cam duplex chain drive
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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.

XJ13 - Building the Legend
Claud Baily’s 1950/51 60° quad-cam 8-litre V12 engine performance data.
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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?

XJ13 - Building the Legend
Claud Baily’s 1950/51 notes.
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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:

XJ13 - Building the Legend
5th December 1960 memo – “POSSIBLE FUTURE RANGE”.
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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.

XJ13 - Building the Legend

25th November 1964 memo – “12 CYLINDER ENGINES”.
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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)

XJ13 - Building the Legend
XJ13 - Building the Legend
Die Casting Quote.
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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.

XJ13 - Building the Legend

XJ6/2 Original twin distributors as originally fitted to XJ6/1.
© Neville Swales.
XJ13 - Building the Legend
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.

XJ13 - Building the Legend
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XJ13 - Building the Legend
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XJ13 - Building the Legend
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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.

XJ13 - Building the Legend

1967 (original car)
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XJ13 - Building the Legend
1973 (rebuilt car)
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The words Jaguar, Jaguar XJ13, XJ13 are used in a historical/descriptive context and in no way suggest our recreations/replicas are approved by Jaguar. It is widely known that there was only ever one Jaguar XJ13 and any others can only ever be replicas, facsimilies, tributes, recreations, toolroom copies or similar.