Jaguar XJ13 Replica by Proteus

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Jaguar first discussed the idea of a mid-engined racing prototype in 1960, but it wasn’t until the middle of the decade that construction began.

The design of the body fell to Malcolm Sayer, the man responsible for the Jaguar C-Type and Le Mans-winning D-Type. As with those legendary machines, Sayer’s experience as an aerodynamicist with the Bristol Aeroplane Company could be seen in the XJ13’s low profile and lithe curves. Naturally for a racing car, aluminium was to be used for the bodywork. The task of fashioning it fell to Bob Blake, described by his contemporaries as ‘an artist in metal’.

The proposed 5-litre V12 was mounted amidships and used as a stressed chassis member together with its five-speed manual ZF transaxle which drove the rear wheels. The front suspension wishbones were similar to those of the E-Type. However, where the E-Type had longitudinal torsion bars, the XJ13 used more conventional coil spring and damper units. The rear setup was also similar to the E-Type, using driveshafts as the upper transverse links. But the XJ13 also used two long radius arms per side, angled back from the body tub together with a single fabricated transverse lower link.

William Heynes, Jaguar’s head of engineering, and his team were developing and building a whole new engine for the car. Jaguar had considered the manufacture of a DOHC V12 engine as far back as 1950. Whilst Jaguar’s earlier 6-cylinder XK engine had been pressed into racing service, it had been designed primarily for road use. The new V12 was aimed squarely at the racetrack and a return to Jaguar’s glory days at Le Mans.

The design was essentially two XK 6-cylinder engines on a common crankshaft with an aluminium cylinder block, although there were differences in the inlet porting, valve angles and combustion chamber shape. In July 1964, Jaguar began assembly of the first quad-cam prototype V12 and in December a second was begun (although only six engines were ever built in total).

By March 1966 the first prototype was running. For on-track development, Heynes, thought it best to bring in an experienced racer as the new car’s main development driver. He recruited David Hobbs who would achieve an unofficial UK closed lap record with the XJ13 which stood for 32 years. (It was only beaten in 1999 by the McLaren F1 by just over 6mph.)

However, although the development of the XJ13 was treated seriously by its designers, the project was never a priority for company management. Even less so following the 1966 merger with BMC. By that time Ford had won Le Mans with the GT40. The XJ13 was considered obsolete by the time the prototype was complete. Testing only confirmed that it would have required considerable development to make it competitive.

The XJ13 was brought to MIRA one last fateful time, to shoot a promotion film for the impending V12 E-Type. High on the banked track, in the hands of Jaguar test driver Norman Dewis, the XJ13 lost compression in a rear tyre, crashed heavily and was virtually destroyed, Dewis being lucky to escape with his life by throwing himself under the bulkhead at the last possible second. With bodywork rebuilt by Abbey Panels, the XJ13 is now displayed at the Heritage Motor Centre Museum at Gaydon.

Few have dared to attempt to replicate one of Malcolm Sayer’s most mythical shapes. But if anyone could pull off a replica of the XJ13, it is surely Proteus, who have made such beautiful renditions of other automotive legends such as the Jaguar C- and D-Types.

In the true spirit of the neglected XJ13, this car was a 'barn find' in so much as it was an incomplete project that was recovered from an outbuilding in Belgium in 1999 by John Gregson who had recently taken over Proteus.

Believed to have been built in the early 1990s, it has a steel spaceframe to which a part-aluminium-part-GRP body has been attached. The bulkhead, floor, bonnet, sills and side vents are aluminium while the bootlid, doors, front and rear mouldings are GRP. Twin aluminium fuel tanks (foam filled) are housed on either side of the car in each sill.

The car is loosely fitted with a fuel-injected V12, thought to come from an XJS, and has a Renault transaxle. Front suspension is mainly E-Type while the rear suspension is hybrid XJ40/XJ6 with outboard disc brakes (the rear discs and callipers are missing but are Jaguar X300 items so will be easy to source). The cast alloy wheels are original Proteus-stamped items with knock-off chromed spinners. Included in the package are some original Proteus drawings for the car, done by Jim Marland, which also include specifications for an all-aluminium version.

The vendor acquired the car from John Gregson in 2001, intending to get it finished off and up-and-running within a matter of weeks (a task which he still believes is eminently achievable). However, being the managing director of another car making company himself, he finds that he never has a spare second to devote to the XJ13 and has reluctantly decided that the time has now come to pass the challenge on to someone else.

Barring some dash instruments, rear lights, exhaust and numerous trivial bits and bobs no doubt, the car is believed to be substantially complete with the exception of the windscreen, although the vendor has established that, amazingly, Triplex still have the original moulds so getting a new one made should not be a problem.

The sheer beauty of the XJ13, coupled with its one-off ghostly ‘non-presence’ in Jaguar history and its near-fatal destruction at MIRA have turned it into a powerfully seductive legend. Whoever finishes this car will have a chance to experience something of that remarkable fable.

PLEASE NOTE: The last three photographs are for demonstration purposes only but show what an XJ13 should look like. Aerodynamic British coachwork at its very finest.

Images courtesy of Jaguar Cars and Wesley Allison/Motor Trend Classic 

AMENDMENT

This car also comes with a copy of a book about the XJ13 project signed by Norman Dewis.