Having designed and developed the successful Jaguar XK engine under the guidance of William Heynes at SS Cars Ltd, Walter Hassan and the team were tasked to develop a Jaguar 5.0 L DOHC V12 engine when Coventry Climax was purchased by Jaguar in 1963. It was about this time when Walter Hassan convinced Harry Mundy, who had left to become the Technical Editor of The Autocar magazine in 1955 (while there he also designed the Lotus-Ford Twin Cam for Colin Chapman), to rejoin the team, which now included the Jaguar engineer, Claude Bailey, who always worked under Bill Heynes from the days of XK engine development. William Heynes was the executive in charge of the team, who retired in July, 1969.
This engine was initially conceived in 1954 for Le Mans 24 Hour Race by combining two Jaguar XK cylinder heads on a common 60 degree block. The first prototype was assembled in 1964 with LM8 aluminium alloy sand cast block and flanged cast iron liners, EN4A forged and nitrided 7 main bearing crankshaft for 4994 cc (87mm x 70mm). This racing engine, with its intake ports in between the intake and the exhaust camshafts, came out to be the fuel injected 5L DOHC Jaguar XJ13 engine in 1966, but more importantly, it was further developed by the same team into the series-production 5.3 L SOHC V12 engine. This engine, with characteristically long intake tracts connecting the four carburetors on the outside of cam covers to the intake ports inside the V angle, came out to the market on Jaguar E-Type in 1971, on Jaguar XJ12 in 1972, and, together with the later 6.0 L version, remained in production until 1997.
CFA and CFF
After the designing was finished on the 5.3 L V12 and the Jaguar XJ, Jaguar wanted a modern engine for a smaller version of XJ. Although Jaguar had gained access to the 2.5 Litre iron block Daimler V8 with the take over of Daimler in 1960, it was a pushrod engine designed in the 1950s, and was not particularly small or light as it was based on, and had many common components with, the 4.5 Litre version.
In response, Coventry Climax designed an aluminium crossflow chain-driven SOHC cylinder head somewhat similar to the 5.3L V12 head, on FWMV Mk.4 block with a stroked crank and wet sump. Tecalemit-Jackson fuel injection was used for the development on this 2,496 cc CFA V8, and the engine was installed on Leonard Pelham Lee's personal Triumph 2000 Estate.
The testing was promising, and a 1,812 cc CFF version was prototyped, however, this 1.8 - 2.5 Litre baby XJ project was killed along with the V8 engines when British Motor Holdings merged with Leyland Motor Corporation in 1968 for the strategy to eliminate internal competition against what came out to be the Rover SD1.