1966 Jaguar XJ13

The Jaguar XJ13 is one of the most visually appealing cars of all time. It carried a nameplate of one of the most successful marque's at LeMans during the 1950's, Jaguar, with five wins in just seven years. The engine that conjured up the wins for the British marque was a direct descendent of the famed XK six-cylinder that could be found in their successful and stunning line of road going vehicles. Jaguar's reign at LeMans was brought to an end when their D-Type was made obsolete due to new racing regulations which limited engine displacement to just three liters. Jaguar returned to LeMans a few years later with a racing version of their E-Type but it was no match for the potent Ferrari's.

Jaguar's racing program was officially over, but designs continued on a new engine and chassis that cold carry the Jaguar name across the LeMans finish line faster than its competition. As racing regulations became relaxed during the early 1960s, Jaguar saw their chance to return with a V12 engine. The car was drastically different to the prior racing C and D Type cars. It had a mid-engine rear drive layout and a design meant to take advantage of the fast-passed course and sweeping curves of LeMans.

Claude Bailey was given the task of developing a new engine. There were seven prototype engines created with two built to racing specifications and fitted with twin overhead camshafts. The engine was created from aluminum with the six cylinder banks mounted at a 60-degree angle. Experiments were done with carburetion, such as the six twin choke setup, but later replaced in favor of the more advanced Lucas fuel injection system. The carbureted versions produced 445 horsepower in comparison to 500 horsepower with fuel injection. The engine had a displacement size of nearly five liters and could be further tuned to gain a couple hundred more horsepower.

The design duties were given to Malcolm Sayer who had been responsible for designing the C and D-Type race cars of the fifties and sixties. This was another big task, as accomplishments on the racing circuit usually translate into sales for the production based cars. Poor performance usually does the opposite. The crew began with a new monocoque chassis with the layout and engine bay similar to the Lotus 25. Just as with the engine, the chassis was formed from aluminum which eliminated the need for steel subframes to carry the suspension. The engine was used as a fully stressed member and the engine and transmission carried the rear suspension. The Sayer designed body was created from aluminum and was finished near the close of 1966. With all the use of aluminum and other weight-saving techniques, the car weighed in at just under 1000 kg.

This was the Experimental Jaguar Number 13, which served as the basis for the vehicles name, the XJ13. It was brought the track for its inaugural outing in early 1967. This clandestine outing was to test the vehicles capabilities and discover its shortcomings. David Hobbs drove the car on the MIRA track and easily broke the track record. It was now ready for LeMans.

The entire project had been done in secret, as the Board of Directors felt it may have a negative effect on the sale of their six cylinder sports cars. As the XJ13 was being finalized and prepared for serious competition, rule changes were made and immediately the car was obsolete. 1968 regulations for prototype racing cars were set at a maximum of three liters. The Jaguar XJ13 was retired before it ever circled the track in formal competition. Work continued on perfecting the V12 engine for use in production vehicles. By 1971 the engine would enter into production in the third generation of the E-Type. The XJ13 was used in a publicity video. During the taping, a tire blew on the MIRA track and the vehicle was nearly destroyed. This was its first public outing. Jaguar later had the car rebuilt and upon completion was shown at events as both a static display and in driving form. One of the engines, the better of the two, was destroyed due to over-revving. The other engine was fitted but the car could now only be driven at slow speeds. This engine used a welded piston which hindered the car from its true potential. The vehicles sad history does not end there; in recent years it fell off a curb and its sump was punctured. After this, the straw that broke the camels back as it were, the car was retired to the museum. Since then, the 'good' engine has been rebuilt, the body repainted, and the chassis repaired as needed.

The car now resides in the Jaguar Daimler Heritage Museum in the U.K. It is brought out only for special appearances.

by Daniel Vaughan | Dec 2007