1956 Jaguar XK-D D-Type

History

T

he Jaguar D-Type sports cars were produced from 1954 through 1957. These factory-built race cars were similar to the C-Type, but given more powerful engines, improved chassis, and aerodynamic bodies.Walter Hassan was tasked with designing a sportscar for Jaguar. The result was the XK-120 which showed promise on the racing circuit. Although the alloy bodied cars were fast, it would not be a serious contender at the 24 Hours of Le Mans race. Further development was needed. In 1951 the XK 120 C, also known as the C-Type, was prepared and ready for testing at Le Mans. The straight-six cylinder engine had been modified to production 210 horsepower and various other mechanical enhancements greatly improve the performance. Three C-Types were entered in the Le Mans race with two failing to finish. The third C-Type finished strong, winning the event while averaging 93.49 miles-per-hour.Three experimental C-Types were entered in LeMans in 1952. A long tail had been applied to the C-Type in an effort to improve aerodynamics and stability during the long, straight stretches. Unfortunately, all three failed to finish due to overheating problems. For 1953, the use of experimental bodies was scrapped in favor of the tradition bodies. The factory cars were fitted with disc brakes. In the end, this combination proved to be all that was necessary to score top finishes.To stay ahead of the competition, Jaguar began working on a Le Mans replacement for the C-Type, resulting in six D-Types in 1954.The D-Type was constructed of a monocoque-type chassis welded to a subframe. Later versions of the car were bolted, rather than welded, to allow easy detachment.The same XK engine was used, albeit with minor modifications such as the use of dry-sump lubrication. The frontal area to house the engine was decreased. This was to provide for higher top speeds as Le Mans. A large fin was place behind the driver to provide stability at speeds in excess of 150 mph. Due to the new design, additional modifications to the shape and size of the engine were required to fit it into the engine bay. It was tilted 8-degrees, resulting in an off-center bump in the hood. The 1955 D-Types used asymmetrical heads, known as '35/40' heads, with intake valves positioned at 35-degress and exhaust valves at 40-degrees.Four D-Types were entered into the 1954 Le Mans race and were not enough to beat the powerful Ferraris. 1955 modifications propelled the Jaguar marque to its third LeMans victory. A Mercedes-Benz SLR was leading the Jaguar by two laps when it was withdrawn from the race.Though 1955 meant another victory at LeMans for Jaguar, it was a devastating year for the sport. The Mercedes-Benz SLR's were poised to capture the victory when a tragic accident occurred, involving an SLR, and killing the driver and 80 spectators. Mercedes-Benz withdrew from the race and from motorsports.Most of the D-Types were single seaters and built for the race track. During the final year of production, Jaguar offered the Jaguar XKSS, a street version of the race car.Twenty-five of the 68 Jaguar D-Type race cars were left unsold when Jaguar decided to cease its participation in the International Sports Car Racing program. Jaguar decided to convert the 25 remaining vehicles into road-worthy sports cars.The rear fin was removed, bumpers were added, and the single-seater was left topless with a canvas hood available to protect the driver from the elements. A windscreen was designed and a second door was added to accommodate passengers. With a Dual-Overhead Cam straight-six cylinder engine with 3442 cc capacity, the vehicle could race from zero to sixty in 7.3 seconds. The 250 horsepower output was capable of propelling the car to a top speed of nearly 150 miles-per-hour. Excellent stopping power was provided by the 4-wheel disc brakes.In 1957, the XKSS was introduced at the New York Auto Show.Sixteen private buyers purchased the XK-SS with the majority going to the United States. Two went to Canada, one to Hong Kong, one in the UK, and the rest to America. There were over 300 examples being built when a fire destroyed the machinery, assembly line, and most of the XKSS models. Steve McQueen, a film star and motor racing fan purchased one. McQueen is famous for his documentary of the 24 Hours of LeMans.

By Daniel Vaughan | Mar 2006