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

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.

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