Introducing the tera®

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 power the sublime 1966 XJ13 Le Mans Prototype and return Jaguar to its glory days of Le Mans triumphs and domination. Sadly, the XJ13 was destined to never turn a wheel in anger and the potential of its mighty power-unit was never fully realised. Instead, Jaguar re-designed Baily’s racing engine into a SOHC version more suited for road-use in their rather more sedate road cars.

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 XJ13 was destined to never turn a wheel in anger and the potential of Baily’s mighty power-unit was never fully realised. Instead, Jaguar re-designed Baily’s racing engine into a SOHC version more suited to sedate applications.

In the words of Jaguar’s 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.

Public launch:

To hear more about it, why not come and visit us at Race Retro on stand 2-136 21-23 February 2020 | Stoneleigh Park, Coventry

For further information visit: www.BuildingTheLegend.co.uk

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:             250 – 650 hp   (261 – 485 kW)
  • Torque:            300 – 600 lb ft (407 – 813 Nm)
  • Compression:  11.7:1
  • 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 Jaguar.

tera®

“to the power of 12”

from the Greek – “teras” = monster.

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

Walter Hassan – Bentley, ERA, Coventry-Climax and Jaguar

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

As part of my research into the background of my prototype V12 engine 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.

XJ13 - Building the Legend
Walter Hassan on his 90th birthday with fellow designers and veteran cars.

As previously revealed, the engine installed in my first 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 has been restored 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:

“… 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 meet the regulations for prototype sports cars the unit would have to be of 5 litres capacity and in order to provide the maximum potential in power, a 12 cylinder ‘Vee’ configuration with a short stroke of 70mm 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.”

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 …“. 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.

XJ13 - Building the Legend
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.

XJ13 - Building the Legend
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”.

XJ13 - Building the Legend
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.

XJ13 - Building the Legend
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.

XJ13 - Building the Legend
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.

XJ13 - Building the Legend

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.

XJ13 - Building the Legend
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.

XJ13 - Building the Legend
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.

XJ13 - Building the Legend
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.


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.

Recreating the XJ13 – Old Technology meets New

Where did Jaguar source components in period? 

Although Jaguar were able to raid their “parts bin” for some components of their XJ13 Le Mans Prototype, most of the car’s major items were custom-made. “Off-the-Shelf” components used in period included things such as Lightweight E-Type (LWE) front suspension & steering rack (albeit modified), instruments, lighting and front wheels (as also used on the rears of LWE racers). However, major components used for the car’s rear wheels, drivetrain, power-unit, braking systems and rear suspension had to be custom made in period.

The engine and associated castings such as bellhousing and rear hub carriers were, of course, designed in-house by Jaguar. The prime architect of the mighty quad-cam engine was Claude Baily under the direction of William Heynes. These major components were drawn up within Jaguar’s Drawing Office, signed off by Baily and casting carried out by The West Yorkshire Foundry. Final finishing of items such as engine blocks and heads was entrusted to Coventry Climax before being returned to Jaguar for final assembly.

The “old skills”

In the mid-1960s design was pretty much a “pen-and-paper” exercise drawing on the designer’s skills, knowledge and hard-won experience. These drawings were translated into real-world components using intermediaries such as wooden patterns (for casting) and wooden bucks/formers for things such as body shapes and some suspension components. “Fettling” and finishing of the final items relied on the manual skills and experience of Jaguar’s engineers.

As well as creating the engineering drawings themselves, the skill needed to produce things such as wooden patterns should not be underestimated. For example, wooden casting patterns need to be made slightly larger than the finished item to take account of shrinkage of molten metals – different metals need different degrees of compensation. Wooden patterns also need to include “draft” and “fillets” such that they can be satisfactorily removed from the casting sand.

The following drawings show these first steps in producing a finished component – in this case, the front upright (hub-carrier) as used in our re-creations.

Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Example engineering drawing for Lightweight E-Type front upright (hub-carrier)
Critical dimensions have been deliberately blurred for the web.
© Building The Legend Limited
Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Notes for pattern-maker and machinist included on engineering drawing
© Building The Legend Limited

Wooden patterns made from the above drawings could be similar to those pictured below:

Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Wooden patterns produced from engineering drawings above.
© Building The Legend Limited

These wooden patterns could then be used to sand-cast final components in the traditional manner. In the case of items such as these uprights, and in the days before metallurgy was advanced enough to be able to produce castings with similar properties to forgings, the engineering drawings could be translated into dyes for use in the forging process.

The skills of those who could design, draw and create such components in the days before Computer Assisted Design (CAD) and techniques such as 3D-Printing were quite remarkable. Don’t forget they didn’t just produce the components but also produced components which were fit for purpose and able to take the designed stresses placed on them. The skills extended from the designers, through those casting/forging the components, to the final machinists.

In particular, the skills of people such as the late Malcolm Sayer when translating his complex body shapes into wooden bucks were quite outstanding. Sayer worked with a precursor of today’s computerised 3D techniques – in his case, the complex maths was arrived at manually using log-tables with typical accuracies of four-figures and more. Nowadays, we have the luxury of computers which greatly assist the process.

In with the new

Today, we are able to design and, in some cases, produce a finished component entirely within a computerised environment. In addition, it is possible to investigate the performance of a component in a completely virtual environment – seeing how the component will respond to various stresses, how it will perform in concert with other virtual components as well as basics such as finished component weight, centre of gravity etc. All this can be done before the component is actually manufactured in real life.

SolidWorks is the CAD programme favoured by Building The Legend Limited. It lends itself to reproducing complex components such as cylinder heads and is preferred to 3D-Scanning for such items. For example, the following pictures show our digital recreations of a 6-cylinder “XK” head as well as a SOHC V12 head. These models were produced as a precursor to a separate project where we are producing quad-cam V12 engines of our own.

Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Digital representation of 6-cylinder XK engine
© Building The Legend Limited
Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Digital representation of V12 SOHC “A-Bank” Head
© Building The Legend Limited

Going back to the example of Jaguar’s LWE upright (used in the original XJ13 and not now available “off-the-shelf”), CAD and 3D-Printing was used to create the various moulds used to cast the finished component. Those of you familiar with this component will see it has been modified slightly to enable the use of modern “sealed-for-life” lower ball-joints.

The material used was EN-GJS-500-7 – a spheroidal graphite cast iron which approaches the strength of equivalent forgings. The following pictures show the finished items.

Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Front Uprights
© Building The Legend Limited
Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Finished machined Front Uprights
© Building The Legend Limited

We were able to use this marriage of old and new techniques to produce items for the project such as bellhousings (both for the prototype DOHC engine as well as later SOHC engines). In the case of the later SOHC bellhousings, “traditional” casting was carried out at a traditional foundry in Nuneaton, close to Coventry. The first stage was for us to design the bellhousings using CAD. The aim was to end up with something cosmetically similar to the original XJ13 item but suitable for use with the later SOHC V12 blocks (5.3, 6.0-litre and larger).  The SOHC bellhousing is sized to accommodate either single- or multi-plate clutches (XJ13 used a twin-plate racing clutch as is the case with our prototype-engined car).

We also took the opportunity to “beef-up” the design to cope with the way the drivetrain is stressed in its unique XJ13 application. Derek White of Jaguar designed the engine as a stressed member in the XJ13. Colin Chapman didn’t come up with this concept until his Lotus 49 of 1967 which means Jaguar would have been first to use this configuration if they had raced in 1965 or 1966.

Here are some pictures of the finished CAD SOHC bellhousing model:

Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
SOHC Bellhousing
© Building The Legend Limited
Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
SOHC Bellhousing
© Building The Legend Limited
Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Building The Legend’s SOHC Bellhousing attached to modified Quaife ZF Transaxle
© Building The Legend Limited

These CAD models were then used to produce the various molds needed for traditional sand-casting.

Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
SOHC Bellhousing Mold
© Building The Legend Limited
Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
SOHC Bellhousing Mold
© Building The Legend Limited
Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
SOHC Bellhousing Mold
© Building The Legend Limited

The actual molds were produced using a combination of 3D-Printing and CNC-Machining. The following video shows them being used to cast the finished items in the traditional way. I was joined on the day by ex-Jaguar Peter Wilson (ex-Competition Department and author) and Nigel Boycott (ex-Jaguar Service Department). The process was described to us by Malcolm Hammersley of GPD Developments.

The bellhousings ended up as follows:

Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Cast SOHC bellhousing
© Building The Legend Limited
Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Cast SOHC bellhousing
© Building The Legend Limited
Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Cast SOHC bellhousing
© Building The Legend Limited

The runners etc were then removed:

Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
Cast SOHC bellhousing
© Building The Legend Limited

We then machined the bellhousings as shown in the following video:

Similar techniques are being used to replicate other items such as rear hub carriers (unique to the XJ13 and certainly not available “off-the-shelf”!):

Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
SOHC Rear Suspension
© Building The Legend Limited
Jaguar XJ13, Building The Legend, Jaguar, 3D Engineers, 3D Engineering, Neville Swales
SOHC Rear Hub Carrier and Dunlop-Style Brakes
© Building The Legend Limited

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.

We need some rivets ……

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

STOP PRESS – Since I first posted this article I have discovered a source of original and genuine Avdel Rivets – as used by Jaguar in 1965 when building the XJ13. They aren’t made anymore and are damn expensive (just over £1 EACH and I need thousands ….) BUT they are the genuine article and I don’t need to resort to modern-day Chinese equivalents 🙂

XJ13 - Building the Legend
Original Avdel 4000-series Dome Head L86 Light Alloy Rivets. Oldest remaining stock is purple and most recent production is plain aluminium.

We need some rivets” said Paul at the bodyshop working on creating my 1966 XJ13 recreation).

OK” I replied, “What kind do we need?“. Paul scratched his head and answered, “Dunno – I suppose we need to find out what Jaguar used in 1966“.

Little did I know that this exchange would lead to. It seems that rivets aren’t as simple and boring as I had first thought. For the benefit of others who may follow us along a similar path I thought it would be worthwhile recording what I learnt about rivets (don’t laugh – rivets really do have an interesting history). Ever wondered how primitive man over four thousand years ago attached handles to the first metal tools and weapons? You guessed it – rivets. How do you attach an aluminium skin to an airframe when aircraft designers switched from wood to metal? – rivets. How do you join almost any kind of dissimilar materials (wood, bone, metal etc) when you don’t have welding or adhesives? You got it – rivets.

Check out the following picture:

XJ13 - Building the Legend

What do you think these are examples of? You guessed it (see the common theme?) – rivets. Only this particular rivet is from the late Bronze Age (1000 BC to 700 BC). It is a copper alloy rivet with two domed heads and has about eleven longtitudinal facets – probably resulting from manufacture. Some of these faces have longtitudinal grooves, perhaps caused when parts of the surface were shaved off with a tool. The more eagle-eyed amongst you will note the domed heads aren’t parallel to each other but are at about 18 degrees from each other. The size, form and condition suggest its probably a rivet from a late Bronze-Age dirk, rapier or sword.

XJ13 - Building the Legend

But what has this got to do with Jaguar, the XJ13 or the price of fish?

Probably not a lot but, skip forward a few thousand years and place yourself in the shoes of the XJ13’s designer, Malcolm Sayer. A man steeped in aerodynamics and a former student of aerodynamics at Loughborough University’s Department of Aeronautical and Automotive Engineering. After graduating from Loughborough he joined the Bristol Aero Company where he worked on various projects including their radial engine. Aircraft and aerodynamics were in his blood and he naturally settled on the same principles of construction to Jaguar’s cars. Chief amongst these methods of construction? Go on, hazard a guess ….

The fasteners of choice in 1965/66 were “Avdel” – short for “Aviation Developments”. Anyone think (as I did) that “rivets were rivets” and were pretty much like today’s pop rivets? There’s a bit more to it than that. The clue as to which rivets were employed by the builder of the car (the late talented Bob Blake) was given by Peter Wilson (someone who can genuinely lay claim to having participated in the build of the original XJ13). Peter recalled Blake’s use of “Advel” rivets and the fact that the car “looked like a porcupine” during its build. Those of us who have used modern “pop-rivets” will know that the stems are broken off during application but the stems of the original Advel rivets remained in place and the protruding stems were later cut off and the face of the rivet shaved flat. When the rivets were first applied the sticking-out stems gave the “porcupine” effect.

XJ13 - Building the Legend
“Porcupine” effect

So how did these Avdel rivets come about?

In 1936 from a small shed in Godalming Surrey Stanley Thomas Johnson started a business called Aviation Developments.

XJ13 - Building the Legend

The company was established to manufacture & supply riveting technology, to a number of industries, but primarily for the rapidly developing Aviation industry. This industry was soon to mushroom as the world responded to the antics of a moustachio’d individual after 1939. In 1936, wood was rapidly giving way to aluminium for aircraft manufacture and a reliable means of fastening was required. Initially these aluminium and steel structures were assembled using solid rivets that were slow to install, requiring two operators with access to both sides of the components to be assembled.

Supermarine Spitfire

Working with the pioneering UK Aviation Engineers of the time one of Aviation Developments Engineers, Jacque Chobert, invented a radical new riveting technology, the Chobert® riveting system.

XJ13 - Building the Legend
Types of rivet

Initially Chobert® fasteners could only be installed one at a time. Aviation Developments Engineers soon recognised this limitation and set about developing a tool capable of installing multiple fasteners before requiring reloading.

XJ13 - Building the Legend
XJ13 - Building the Legend

The Chobert® system allowed rivets to be installed by a single operator using a hand tool accessing one side of the riveted joint – significantly reducing both assembly times and costs. The concept of assembly from a single side of the application became generically known as blind fastening. This advanced system was quickly adopted by the UK Aviation industry and proved invaluable in building more than 20,000 Spitfire fighter aircraft (yes – you read correctly – 20,000 Spitfires) over a period of eight years that were key to the success of the Battle of Britain.

XJ13 - Building the Legend
Supermarine Spitfire

During the late 40’s and 50’s the global aviation industry moved into the jet age and sales of the Chobert® increased as it became an industry standard fastening technology.

As well as expanding both the range and sales of the Chobert® system the company developed engineered fastener and assembly solutions for other industries. Unsurprisingly, Malcolm Sayer adopted these types of fastener for prototypes and racing cars. However, he did continue to make use of hand-applied countersunk solid rivets to minimise disruption to airflow where needed. The following picture shows examples of solid rivets which could only be applied if there is access to both sides of the join:

XJ13 - Building the Legend
Solid aluminium rivets. Countersunk (left) and Domed (right)

Malcolm Sayer was very much a perfectionist when it came to the aerodynamic properties of his designs and used these countersunk rivets as far as practicable. Indeed, Peter Wilson recounts in his definitive book on the XJ13 …

“… Bob Blake had found a small winged Jaguar badge which he thought would look rather nice on the front of the car. He carefully made a depression in the nose panel, the exact shape of the badge, such that it sad almost flush with the skin surface. No sooner had he done this that Malcolm Sayer made one of his regular visits to the shop to see how things were progressing. Malcolm took one look at the badge and obviously did not like what he saw. He asked Bob who had fitted it. ‘I did’ said Bob. ‘Well take it off!” Malcolm insisted. ‘It will disrupt the airflow over the front of the car.’ … Bob removed his badge and beat out the depression.”

The nose of the original 1966 XJ13 was left smooth by Malcolm – presumably for aerodynamic reasons. However, one of the many changes made during the rebuild of the crashed car in 1972/73 was the addition of a row of domed rivets across the nose of the car – clearly wrong when compared with the 1966 original. Needless to say, my 1966 recreations have the smooth nose Sayer intended.

Yet another difference is that the rivets used during the rebuild were larger than those used originally. This was probably because the original rivets were drilled out and so larger ones were now needed to fill the enlarged holes.

XJ13 - Building the Legend
Original 1966 car

By the 1950’s Aviation Developments was focusing on providing new assembly solutions. The two part Avdel® breakstem aerospace rivet was introduced offering improved rivet strength, different head configurations, diameters and material options. When installed the stem breaks above the head and is machined off. When painted countersunk forms of the rivets where almost invisible. These fasteners were used in many areas of the aircraft including ailerons, flaps, engine pods, elevators, rudders, tail planes, fins, doors & floors. In 1961, to reflect its broadening product portfolio and cross-market/industry capability, Aviation Developments changed its name to Avdel® and opened its new manufacturing facility in Welwyn Garden City, Hertfordshire.

XJ13 - Building the Legend

One of the first products developed by Avdel was the Avex® multigrip breakstem rivet. It was introduced to the market with the compact 734 hydro-pneumatic hand tool. The world’s first multigrip fastener quickly became a flagship product for Avdel that would remain unchallenged across automotive, industrial and electronic market sectors for the next 20 years. It is this product that was almost certainly used by Bob Blake when building the original XJ13.

XJ13 - Building the Legend

Advel the company still exists today and they offer a close equivalent to the rivet originally supplied to Jaguar.

XJ13 - Building the Legend

Sadly, the Avdel manufacturing facility at Welwyn Garden City was closed down in 2005 and manufacturing was transferred to Wuxi in China.

XJ13 - Building the Legend
Closure of Advel’s Manufacturing Facility in 2005 when production was transferred to China

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.

Classic Workshop

Building The Legend Limited

Building The Legend Limited, creators of the sublime Le Mans Prototype inspired by Jaguar’s one-and-only XJ13, is proud to announce our extension of services to owners of classic Jaguars and our aim of matching their passion with our attention to detail and craftsmanship.

Based close to Jaguar’s spiritual home in the heart of Coventry our fully-equipped and staffed new workshop opens its doors to fellow-enthusiasts and owners of Jaguar E-Types, Classic Saloons and race-cars – whether re-creations or original.

Building The Legend will collect and deliver vehicles for service, repair and rejuvenation from and to any location in the UK or, in the case of overseas customers, any UK airport or port.

The expert engineers at our Classic Workshop are ready to help preserve and rejuvenate classic Jaguar cars from around the world.

One of the many services we offer is comprehensive rebuilds of Jaguar’s classic 6- and 12-cylinder engines – professionally built to the highest standards. We can rebuild your own matching-numbers engine, supply replacements on an exchange or outright basis. Engine removal and replacement service is also available at competitive rates.

Your “Building The Legend” Classic XK Engine

When your engine arrives it will be photographed and all serial numbers and components noted. This ensures that you will have your own unit and ancillary parts returned.

We can remove and replace your engine for you in our comprehensively-equipped workshop. We can also collect and deliver your car as required.

Your engine will be fully stripped and chemically cleaned, after which all components will be inspected by our Jaguar time-served senior engine builder – one of the UKs most experienced builders of classic Jaguar 6- and 12-cylinder engines. He is a Jaguar engine specialist. Specialising in the rebuilding and reconditioning of classic Jaguar engines. All Jaguar engines from 1948 -1979. XK120, XK140 and XK150. E-type engines 3.8/4.2 and Jaguar XJ6, XJ12 and XJS V12 engines. He has over 40 years specialist experience with rebuilds and reconditioning of Jaguar engines. He joined Jaguar as a works apprentice in 1971 and went on to work in the factory engine reconditioning department, working on all derivatives of the XK and V12 Jaguar engines.

He began his apprenticeship at Jaguar in 1971 and remained with Jaguar for the next ten years. His start at Jaguar coincided with the launch of their Series 3 V12-powered E-Type and he gained enormous experience assembling and rebuilding these legendary engines. As well as the V12, he has worked on the whole range of Jaguar power-units – from fighting-vehicle engines, through fire-truck engines to their production and race engines.

3.8 cylinder block Degreased, Acid dipped, rebored, steam cleaned and wire brushed ready for painting

Crankshafts, conrods, blocks and heads will be inspected for cracks and suitability for overhaul. From here your engine components will pass through the machine shop. Crankshafts will have the journals ground and polished as required. The complete crank assembly will be balanced. Conrods will be balanced, bushed, sized and matched and have new bolts and nuts fitted.

Cylinder blocks will be checked for main bearing alignment and rectified by line boring if required. Where applicable, cylinder liners will be removed and internal waterways cleaned. Replacement liners will be fitted.

At every stage, you can specify any enhancements/modifications to improve the longevity and power of your engine.

Outside of block etch primed

The block will be rebored and honed to suit replacement pistons and rings. It will then be surface ground and cleaned and painted. New core plugs will be fitted. The bottom end of the engine will then be carefully assembled using top quality, heavy-duty bearings, gaskets and seals. All timing chains will be replaced along with the tensioner and chain dampers. Sprockets and bushes will be checked for damage and replaced as required.

First coat of exterior paint applied

Oil pumps are replaced with standard specification rotor pumps, or up-rated units fitted.

First coat of internal paint applied

Cylinder heads are crack tested, waterways machined and welded as required. Valve guides are inspected replaced and/or linered and are compatible for lead free fuel. Exhaust valve seats are replaced for lead free use and cut to suit valves. Inlet seats are cut to suit valves. Bucket guides are inspected and sized. Larger buckets can be installed to cater for high-lift performance cams if desired. Loose or worn bucket guides are replaced. New valves, springs, stem seals, shims and followers are fitted.

Crankshaft chemically cleaned for inspection

Camshafts are reprofiled as required. Chamber sizes are checked and the head face surfaced. The head casting is refurbished as per original. (Painted and polished to correct original specification). The head is carefully assembled and shimmed and vacuum tested. New manifold studs are fitted.

Ready to fit sludge plugs
Crankshaft split lip seal fitted to crank

The head is then reunited with the block, using new cylinder head studs, chrome nuts and composite head gasket. Cam covers are either polished or repainted as applicable, fitted with new chrome nuts and copper washers. New spark plugs are fitted and installation gaskets supplied.

Bearings fitted to cylinder block

The finished engine unit is then either refitted with the customers own ancillaries (carbs, manifolds, water pump, distributor, filter head, flywheel, crank damper, etc) and hot tested under its own power in our test cell or basic units without customers own ancillaries can be tested under power using our ancillaries.

Crank torqued and thrust set to 0.004 thousandths of an inch

We offer a reconditioning service for carbs, distributors, filter heads, flywheels and crank dampers ‘in house’ at very competitive prices. We are also able to supply, from stock, clutch kits, cooler kits, coils, leads, engine mounts etc.


CONTACT US for details and pricing


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.

America’s Bob Blake – An Artist in Metal

Bob Blake - Jaguar XJ13

As part of my research into Jaguar’s XJ13, I came across the story of the man largely responsible for making the original body – Bob Blake. What follows is the story of a man able to translate the designs of people, such as the legendary Malcolm Sayer, into metal. Contemporaries of Bob Blake described him as “An Artist in Metal”.

Blake was born in 1916 at the Fort Totten Sioux/Dakota Indian Reservation, Elbow Woods, North Dakota, USA. The original Reservation at Fort Totten was located near Devils Lake. After 1905 almost half the land was sold to the Government and opened up for white settlement.

Fort Totten Indian Reservation.

The young Bob Blake took up panel beating as a hobby and was entirely self-taught. He taught himself to weld at the age of 19 and a lifelong interest in racing cars and their construction began.

After entering the services he visited the UK in 1942 with the US Third Army where he met his future wife, Jean. At the end of the war he returned to the US and set up a workshop building sprint and race cars – including midget racers. He didn’t only make bodies, he also lent his hand to making parts such as chassis, fuel tanks, radiators, steering and almost everything else. As his skill and reputation grew, he progressed to work on Indianapolis cars for racers such as Ted Horn and Tommy Hinershitz. One of his early commissions was to manufacture parts for Alec Ullman’s Alfa Romeo – Ullman, a Russian-born MIT graduate went on to found the Sebring 12-hour race in 1950 in an attempt to rejuvenate sports car racing in the US.

Bob Blake remained in touch with Ullman and received a phone call from him in 1950 during a visit to the UK. Ullman told him that Briggs Cunningham had entered two Series 61 Cadillac Coupe deVilles at Le Mans – one with a standard body and the second with a streamlined body. Howard Weinman, an aeronautical engineer, was tasked with streamlining the Cadillac. Weinman began by testing designs in wind tunnels. The resulting design was wide, had a low center of gravity, aerodynamic, and lightweight due to an aluminum body. Many people agreed that the appearance was not favorable and it received the name ‘Le Monstre’ by the French press. During preparations for the event, the standard car had been driven into the back of ‘Le Monstre’ and both needed urgent repair.

1950 Cadillac ‘Le Monstre’.

Bob Blake immediately flew out to Le Mans and worked non-stop without sleep for 48 hours to repair the cars. He succeeded with only minutes to spare before scrutineering.

In the race, Cunningham and Phil Walters were the drivers of the ‘Le Monstre’. The coupe was driven by Miles and Sam Collier. The traditional sprint start, where the drivers sprinted to their vehicles, revealed the doors were locked. The problem was able to be solved by reaching in through the window and unlocking the door – not a good way to start a race! On the second lap, ‘Le Monstre’ lost control and ended up in a sandbank where it sat for twenty minutes before Cunningham could dig it out. ‘Le Monstre’ was now four laps behind. The Coupe had a bit of misfortune as well. Part way through the race, it had to come to a complete stop while a stray dog made its way across the track. Later on in the race, it barely made it back to the pits due to low fuel. When the checkered flag fell, both cars were in impressive standing. ‘Le Monstre’ had battled its way back from 35th place to finish in 11th. The coupe was in 10th after averaging 81.5 mph per lap. To finish the race was a major accomplishment, a testament to both driver and car. Their accomplishment was even more significant since the Coupe had lost its first and second gears during the race.

Cunningham’s ambition was to win at Le Mans with an American car and, to this end, set up a company in 1950 with Alfred Momo. Bob Blake’s efforts at Le Mans had clearly impressed Cunningham and he employed Blake in his new company – giving Blake overall responsibility for building his Le Mans contenders. Bob Blake built every Cunningham car until the closure of the company in 1955. Although Briggs Cunningham never realised his ambition, he did come a creditable fourth in his Blake-built C-4R in 1952 and finished a respectable third in 1953 behind the winning Hamilton/Rolt Jaguar C-Type.

Briggs Cunningham held Bob Blake in high regard and, when he closed his company in 1955, he wrote a glowing reference for the jobless Blake:

XJ13 - Building the Legend
The Bob Blake-built C-4R on its way to fourth place at Le Mans in 1952.

” … He designed and built all our competition cars that raced at Le Mans from 1951 thru 1955, doing most of the work himself. He is one of the best aluminium welders and formers in the USA, and we found him invaluable in our racing department. Bob is a most efficient worker, and a real artist in sheet metal work of all kinds.”

“His character is excellent, and his interest in his job profound. He loves racing cars of any kind, and is a wonderful man to have in the team at races, as he can make all manner of alterations and repairs very quickly, when the need arises. Bob was one of our most valuable team members, and I would highly recommend him to any firm or individual looking for one of the best body men in the world today. His loyalty is outstanding, and I frankly hate to lose him.”

XJ13 - Building the Legend
Bob Blake (far right) at Cunningham’s company.

Bob Blake had come into contact with people such as Lofty England and other racing team members whilst racing with Cunningham and so was already known to them. In November of 1955 Blake joined Jaguar and began an association that continued for more than twenty years.

One of Blake’s first responsibilities was to convert the stock of obsolete D-Type racers into road cars – the XKSS cars. He altered the D-Type body and added parts such as bumpers and hood frame. In his own words, Bob Blake said,

” … I made all the frames and bits and pieces, including all the wooden tools to make everything from. I made the first set of bumpers by cutting down the big old bumper, using the top radius and the bottom radius, cutting the flute out and welding the two pieces together.”

XJ13 - Building the Legend
Jaguar XKSS – note the diminuitive bumpers that were to make a return in the E-Type.

Bob Blake was a likeable character who forged relationships with William Lyons and Malcolm Sayer amongst others. Bob worked very closely with Sayer and was able to decipher his mathematical representations of compound curves and produce panels from the data. Malcolm Sayer’s way of working was a longhand precursor of the digital CAD techniques used today and he was very much a pioneer in this field. It is pleasing for me to realise that I am using today’s equivalent of Malcolm Sayer’s calculations in the construction of my XJ13 recreation. Sadly, neither of these two gifted individuals are still around to lend the benefit of their expertise.

After the XKSS, Bob Blake worked closely with Malcolm Sayer in the production of the first E-Type prototype – E1A. Indeed, Bob Blake went on to play a major part in producing the E-Type coupe. Working with an E-Type roadster, he tried different roof treatments within the Competition Department. He said, ” … I had a body in the Comp. Shop … I took a whole mess of 1/16 steel rods and did a profile, a side elevation of the screen and the roof, flowing into the tail. I’d got all this tacked up and Sir William walked in the door.”

“The Old Man looked at it and boy, he liked it. He fell in love with it the minute he walked in the shop. Lyons studied the mock-up for some time in silence, walking around it. He said to me, ‘Did you do this, Blake?’ I said ‘yep’. He responded ‘Its good. We’ll make it!’ “

XJ13 - Building the Legend
Jaguar E-Type Coupe.

In 1962 Bob Blake became involved in the car that represented Jaguar’s hope to return to racing – the Lightweight E-Type. Peter Wilson, in his book “Cat Out of the Bag” (available from Paul Skilleter Books at /www.paulskilleterbooks.co.uk) reports,” .. It was early October (1962) when Bob Blake and Geoff Joyce started work on the first bodyshell. Malcolm Sayer, our aerodynamicist and designer of the D-Type monocoque, had meantime designed an aerodynamic package, consisting mainly of a special coupe top, with the combined objective of reducing both the aerodynamic drag and the frontal area. 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 surface definition by a German, when they spent a few days together in a tent in the desert, during his time working in Iraq at Baghdad University, soon after the war. It was a system that was relatively easy to use; just a case of marking out the points defined by the co-ordinates on a sheet of plywood, cutting it out, then assembling each piece relative to its datum on to a wooden base and, ‘hey presto’, you had a complete skin former…”

Malcolm kept his method of mathematically calculating complex surfaces close to his chest … from Malcolm’s drawings, Bob and Geoff, together with Sam Bacon, built a wooden ‘egg-box’ former for the coupe skin.”


Similar documents have survived – defining things such as the windscreen profile, suspension and steering points etc. Data from these are being incorporated into the digital model which will be used to manufacture a similar “egg-box” former for my XJ13 recreation.

In 1965 Bob Blake worked on the XJ13 project. His method of working is best described by Peter Wilson, ” … As our surface table was not large enough, or indeed remotely suitable, Bob Blake, Geoff and Roger built a rigid wooden platform on which to build the XJ13 monocoque … First they constructed a perimeter wooden frame from a 6×4-inch timber, cross-braced at intervals along its length. This was topped with 3/4 inch thick plywood sheet, which they then marked out with ’10’ lines to enable accurate positioning of each of the myriad of construction reference points defined by Malcolm Sayer’s ‘drawings’ “


” … the monocoque was constructed almost entirely from NS4 2 percent magnesium and 2 percent manganese, half-hard alloy sheet, mostly of 18 swg thickness (0.048 inches), together with some sheet steel pressings in areas of high and concentrated stress, such as the main engine mountings and front suspension attachment areas.”

” … The floor section and outer sills were formed in two halves and were joined along the centre line of the car with an overlapping, joggled joint and a double row of rivets. The inner sill panels were made up and these, together with the internal half-rounded section inner sill stiffeners, four per side, were assembled to the floor section. At this point the whole job was shipped over to Abbey Panels at Exhall on the outskirts of Coventry for the inner and outer sill joints to be roller welded using their specialised equipment. … This was then the sole contribution Abbey Panels made to the construction of the original monocoque. With this operation completed and the basic foundation of the monocoque firmly in place, construction proceeded apace with Bob, Geoff and Roger fabricating the majority of the panels and rivetting these in place, while the rest of us helped out with the simpler body items.”


Peter Wilson talks of Bob Blake in his book, “Cat Out of the Bag” and Bob’s personable character shines though. “… Bob Blake was a totally unique talent. He was a hands-on man, who also had a superb eye for style. Not only could he create a vision of shape and style, but he could then actually make it. He was the ‘complete’ body man and Jaguar were lucky to have his talents … Bob was a super bloke, modest, self assured and always helpful. He did not suffer fools lightly and many is the time whilst I attempted some sheet metal work he would appear at my shoulder and say, ‘Not like that you silly shit! Here, let me teach you how to do it properly.’ And with great patience he would do just that.”

XJ13 - Building the Legend
Bob Blake in later life.

Rather amusingly, Peter Wilson talks of Bob Blakes “Secret Project”. It seems that Bob Blake became rather more industrious than usual and was seen to be squirrelling various car components into the Competition Shop. The secret was eventually revealed to be his personal Ferrari project – a rather mangled 250 GT. The car was soon transformed by Bob into a beautiful blue car – complete with engine rebuilt at home by George Buck! Bob continued his interest in buying and repairing crash-damaged Ferraris and in the 1970s could be seen driving one of his three Ferraris – a 365 Daytona and two GTB 330s.

Described by his other contemporaries as a “delightful gentleman”, Bob Blake retired to Northampton in 1978 with his wife and kept his hand in by fabricating small projects such as motorcycle fuel tanks for friends.

This talented key player in the story of Jaguar and the XJ13 passed away on 26th August 2003 at the ripe old age of 87.

XJ13 - Building the Legend
Bob Blake’s Ferrari Daytona.

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.

Ready for paint ….

Perhaps a good time to reflect back 50 years ago to early 1965 when Bob Blake had already made a start on the original’s monocoque.

At the time, it was believed that it was still possible to have the car up and running in time for Le Mans – time was very, very tight but the skilled team working behind closed doors were used to working to such tight deadlines.

From the perspective of the Competition Department Engineers, as described by Peter Wilson in his definitive book on the XJ13 (“XJ13 – The definitive story of the Jaguar Le Mans car and the V12 engine that powered it” – available from the publisher Paul Skilleter and the JCNA website )

… “That the Competition Department had the capability to build XJ13 to a similar schedule was in no doubt, especially as by 1965 there were three more people working in the department. One thing was missing, however – the final directive, which could only come from the top. To build E2A had required the entire CompetitionDepartment workforce, working seven days a week, together with similar levels of effort from the Experimental Engine Department to build and develop the 3.0 litre all aluminium racing engine. This total commitment from top management in respect of the XJ13 was not forthcoming probably due to other top level priorities which we couldn’t have been aware of …

… But it was becoming obvious that there was no way the car would be ready for Le Mans in 1965.”

The Competition in 1965

In January of 1965 the annual Racing Car Show was held at Olympia in London where the latest designs were being showcased by designers such as Lotus, McLaren, Lola & Brabham. Derrick White (Jaguar’s pre-eminent chassis designer) and Malcolm Sayer attended the show. They produced a report on their return in which Derrick made the following significant points:

  • None of the racing cars at the show adopted the practice of using the rear driveshaft to locate the rear wheels. Those of you familiar with Jaguar will know this had become standard practice at Jaguar. Companies such as Lotus and Lola had tried solid driveshafts as upper locating links but had quickly moved to upper/lower links and plunging driveshafts. This fell on deaf ears as far as Jaguar’s William Heynes was concerned and he insisted the XJ13 should retain Jaguar’s “production” setup. Jaguar’s bad experiences with the De Dion independent systems tried on the D-Types in the 1950s may have also influenced his decision. This difference of opinion festered between White and Heynes over the next two years eventually culminating in White leaving Jaguar and pursuing a very successful career designing race-winning chassis for Cooper and the Honda/Lola/Surtees consortium. There is no doubt the XJ13 would have ended up an even more competent car had Derrick been allowed to apply his solutions.
  • Derrick also made a request for more design resource – needed to keep pace with the competition. This request was refused by William Heynes who insisted a pair of hands should be recruited from within Jaguar’s existing complement.

Fast-forward …..

Fast-forward 50 years and to my efforts to reproduce the XJ13 rear suspension geometry.

I was already in possession of all critical suspension points in 3D space so I was well on my way to being able to reproduce the precise handling characteristics of the original car in my recreation. I had already sourced an original ZF 5DS 25-1 transaxle as used in the XJ13 – complete with identical ratios. As predicted by Derrick White, Jaguar did initially have problems with their use of the driveshaft as upper link and the transaxle output shafts had to be modified very early in development. I made the same modifications to the transaxle output shafts to cope with the lateral stresses applied by the use of the solid drive shafts.

Essentially, this consisted of replacing the ZF driveshaft circlips with nuts. The drive shafts were threaded and were held in place by nuts.

Driving the Rear Wheels

Incidentally, I have acquired a pair of drive shafts which had been originally installed in the XJ13. Indeed, it is possible they were in place during XJ13 Test & Development driver David Hobbs’ XJ13 record-breaking run – more than 161 mph on the closed track at MIRA in 1967 – a record which was to stand for 32 years and only beaten in 1992 by the McLaren F1 road car. This record did show the potential of the XJ13 “straight out of the box” and before serious race-development.

nsaxle output shafts before modification – showing circlip attachment
© Neville Swales
Original XJ13 modified transaxle output shafts installed in Neville’s recreation. These items are believed to have been in place in the original XJ13 during its record-breaking run.
© Neville Swales
Original XJ13 rear suspension. “Solid” drive shafts used as upper-links. Note custom cast alloy hub carrier and use of Dunlop brake piston.  
© Reproduced with permission

These output shafts are used to connect the cast rear hub-carriers to the transaxle via a pair of “solid” drive shafts. Again, those of you familiar with your Jaguars will recognise the basic architecture of this setup. The following picture shows the arrangement in the original XJ13:

I recreated the original setup – even going to the extent of recreating custom rear hub carriers, vented discs and custom Dunlop calipers. Although Jaguar later adopted Girling brakes, the car started its life with Dunlop brakes. A handbrake caliper was added but never used.

Sitting on all four feet

Original XJ13 front suspension (left). Based on 1964 Lightweight E-Type with peg-drive hub, vented discs, coil-over shocks in place of torsion bars, Dunlop caliper & removable pistons. Original XJ13 rear suspension (right). Custom hub carrier, peg-drive hub, Dunlop caliper, fabricated lower wishbone, vented disc and handbrake caliper (not used).
© Reproduced with permission
CAD drawing of XJ13 rear hub carrier. Jaguar used a similar process in 1965 but substituted pen & paper for the design and a wooden pattern for the 3D-Printed items! I chose to design his hub carrier so that larger bearings could be used. I also designed it such that wider wheels could be installed without the necessity to add rear wheel-arch flares. A hidden “drum-type” handbrake is incorporated into the design.
© Neville Swales

The following pictures show steps in recreating these custom items:

Heat-treated hubs arrive from the foundry in Coventry for my recreation.
© Neville Swales
Machining the hubs.
© Neville Swales

Batch of machined front hub carriers (left). These are cast using modern materials/treatment giving a strength approaching that of forgings. They are exact replicas of Lightweight E-Type items albeit modified to accept later sealed-for-life bottom bearings.

Front hub assembly (right). Lightweight E-Type hubs and custom vented disc.
© Neville Swales

With the rear hubs installed in the car, the front suspension could be completed.

Left (near-side) front suspension. Adjustable custom anti-roll bar is ¾” EN27 spring steel as original.
© Neville Swales
Left (near-side) front suspension. Note removable Dunlop brake piston fitted to custom cast replica caliper.
© Neville Swales

Oil

My car can now sit on all four feet. Dunlop racing tyres were fitted as original and attention could turn to final details as the recreated car was made ready for the paintshop. One of these details was the addition of a dry-sump oil tank as original. Wheras practically all modern tanks use round tanks where the oil is returned tangentially to remove entrapped air, Jaguar chose a different solution where returned oil passed over a series of baffle-plates in a rectangular tank. The following picture shows the original car’s dry-sump tank:

Original XJ13 dry-sump oil tank. Oil is returned to the top of the tank and passes through a number of perforated baffles for de-aeration before being stored in a lower rubber bag-tank in the sill.
© Neville Swales

The following pictures show the recreated tank. My tank does differ slightly from the original in that the de-aerated oil is stored within the sill in a solid aluminium tank rather than a rubber bag-tank. Much head-scratching was called for during the car’s build at Jaguar for a suitable rubber capable of withstanding hot oil at up to 150 C. I decided to take a more secure option! The tank is capable of holding more than 6 gallons of oil.

Recreated dry-sump oil tank. This picture shows the tank location on the rear left-hand sill. The tank base extends into the sill where de-aerated oil is stored.
© Neville Swales
Recreated dry-sump oil tank. This shot shows one of the sill stiffeners inside the sill. This helps give the structure immense strength as evidenced by Norman Dewis’ unintentional “crash-test” in 1971. The car’s underlying structure survived almost intact.
© Neville Swales
Beginning assembly of the replica oil tank components. The original tank was fabricated by Bob Blake himself. Whilst beautifully-executed, he did seem to favour the use of 3/16” screws which were used extensively. © Neville Swales 
This shot shows the first of the internal downward-sloping baffles being installed. 
© Neville Swales
Lots of 3/16” screws!
© Neville Swales
Final tank.
© Neville Swales

Just in case Malcolm is looking …

I have previously extolled the virtues of the craftsmen working at my chosen bodyshop – North Devon Metalcraft in Devon, UK. One more detail added a few days ago exemplifies the skill of these artisans. I reckon Jaguar’s Bob Blake would have approved had he still been around today.

I needed to install the front indicators. Knowing how particular Jaguar’s Malcom Sayer was about any detail disrupting his airflow, it was very important to ensure these items fitted particularly well and recessed into the aluminium body. Peter Wilson talks of an occasion in 1965 when Bob Blake took it upon himself to install a cast Jaguar emblem on the nose of the car. He carefully traced around it and hammered out a recess so the badge would sit flush. When Malcolm saw what he had done he immediately insisted the badge was removed, the recess removed and the nose hammered flat once more. Bob Blake reluctantly did so.

Wheras Jaguar’s rebuilt car has rows of raised rivets across its nose, the 1966 original made use of flat countersunk rivets in this area to maintain a smooth profile. I am sure the late Malcolm Sayer would not have been amused had he seen what was done to “his” car during its post-crash rebuild. The following pictures show the sequence followed by the chaps at North Devon Metalcraft to properly install the side indicators. I never tire of watching these skilled metalworkers at work:

First job was to fabricate a steel tool which could be mounted in a vice and used to form the recessed aluminium panel.
© Neville Swales
The panel was then held in position using a couple of self-tappers so that a line could be scribed around its perimeter.
© Neville Swales
A hole was cut by hand so the new panel sat absolutely flush with the surrounding metal. I had to look away while John of ND Metalcraft snipped the shape out of my pristine front wing by hand.
© Neville Swales
The confidence, speed and accuracy of the hand cut was quite remarkable.
© Neville Swales
The next step was to attach the panel using a series of tacks applied using TIG.
© Neville Swales
Panel tacked in position.
© Neville Swales
The next step was gas welding. The process of obtaining a continuous weld on such thin-gauge aluminium represents the height of the body-makers art. It has been described as “being constantly a split-second away from disaster”!
© Neville Swales
The finished weld. Now to make it disappear …
© Neville Swales
John begins his painstaking work to disguise the weld. He made it look easy which is the sign of a true craftsman.
© Neville Swales
The weld begins to disappear …
© Neville Swales
The finished item. No filler used and almost impossible to see or feel any kind of join. The final result is a recessed indicator which should have satisfied Malcolm Sayer himself.
© Neville Swales

CAN YOU GUESS WHAT THIS WAS FOR?

NACA duct positioned on XJ13 bonnet.
© Reproduced with permission

The bonnet of the XJ13 has a NACA (National Advisory Committee for Aeronautics) duct. It is placed on the driver’s side and close to the leading edge of the bonnet.

If you look underneath the bonnet you will see the following:

Recreated bonnet with duct as on original.
© Neville Swales

Can any of you guess what this was meant for?

Here’s a few clues … The duct points straight down. It points towards the steering rack and is in the vicinity of the brake and clutch reservoirs. It is positioned on the driver’s side rather than centrally on the car ……….

My car is now in the paintshop. The plan is to reunite it with its engine when it returns then give it a first shakedown run.

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.

Monticello Motor Club, NY

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

First outing in anger for our full-race 6.8-litre SOHC V12 re-creation. Stretches its legs in the capable hands of Robillard Racing team owner and driver – Joe Robillard.

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.

“In the metal”

  • XJ13, Building The Legend, Neville Swales, Jaguar, Ecurie Cars. LM69, tera-, quad-cam, V12

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.