Engine: Description and Operation
DESCRIPTIONThe 6-cylinder engine fitted to Series III Jaguar cars is developed directly from the 3.4 litre unit introduced with the Jaguar XK 120 car in 1948, although superficially very similar, these two engines now have few parts in common and none of the accessories fitted to the current engines are interchangeable with those of the early units. The basic design of the engine has, however, remained unchanged, and the latest units retain chain-driven twin-overhead camshafts, seven main bearings and a stroke of 106 mm (4.173 in) which were incorporated in the first production engines
Major changes have been made in recent years to the arrangements for fuel supply and the reduction of undesirable emissions, and a redesigned, electronically triggered ignition system is fitted to the 4.2L Series III cars.