Jaguar V12 engine

The Jaguar V12 piston engine was one of the premier powerplants of the 1970s and 1980s. It was first seen in the Series 3 Jaguar E-type of 1971 and was based loosely on an earlier design for an intended Le Mans car, the Jaguar XJ13. The V12 was only Jaguar's second engine design to go into production in the history of the company. The all-alloy block was fitted with removable wet liners and had a SOHC two-valve alloy head with flat block mating surface, and the combustion chamber in the piston crown carved in a shallow cup form.

Development

Initial designs for the V12 were produced as early as 1954, with a view to using it in a Le Mans car. The engine was to be a 5.0-litre, quad-cam engine with a high redline, which shared the same basic architecture of the XK cylinder head. After Jaguar withdrew from racing, the V12 designs lay forgotten until 1963 when Jaguar Cars purchased Coventry Climax and, as a result, Walter Hassan who designed the XK engine with William Haynes at SS Cars Ltd, rejoined the team together with Harry Mundy and Claude Baily.

V12 engine

A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders each, usually but not always at a 60° angle to each other, with all 12 pistons driving a common crankshaft. Since each cylinder bank is essentially a straight-six which is by itself in both primary and secondary balance, a V12 is automatically in primary and secondary balance no matter which V angle is used, and therefore it needs no balance shafts. A four-stroke 12 cylinder engine has an even firing order if cylinders fire every 60° of crankshaft rotation, so a V12 with cylinder banks at a multiples of 60° (60°, 120°, or 180°) will have even firing intervals without using split crankpins. By using split crankpins or ignoring minor vibrations, any V angle is possible. The 180° configuration is usually referred to as a "flat-twelve engine" or a "boxer" although it is in reality a 180° V since the pistons can and normally do use shared crankpins.

Applications