The World famous Coventry Climax racing engine

In 1950 (at the time of the Korean war) the specifications for fire-pumps, that the U.K. Ministry of Defence had set, were changed. Army fire-pumps had to deliver 35bhp at 3,500rpm. plus they had to be very light-weight. September of that year, Leonard Lee of Coventry Climax met his new chief engineer, Walter Hassan and they decided that their product needed an up-date.

Hassan took a close look at motorcycle technology (which at the time was ahead of cars), and in particular at the Sunbeam S7. The S7 engine was entirely of alloy, it had wedge-shaped combustion chambers, and an overhead camshaft.

Seven months later, in April 1951, the first 1020cc FW engine was ready, FW for Feather Weight. When started for the first time, it ran successfully, and easily produced 38bhp. They were rewarded with a Home Office contract.

As Mr. Lee thought that victories in races would influence prospective buyers, it was decided that the engine would be raced. Already the gentlemen of the racing business were knocking on his door since the engine had been on display at the Earls Court Motor-show, on the marine stand.

It was obvious that the engine was not developed with racing in mind. The awkward size of 1020cc needed modification and other changes had to be made to make the FW into a racing engine.

In 1953 the FWA was delivered to the market, A for Automobile. The block had been rebored, new pistons were fitted, as were a steel crankshaft and twin carbs, alterations to the valves and ports were made and the compression ratio was increased. Power output of the little fire-pump had been increased from 38 to 72bhp at 6100rpm.

The first car to use a Coventry Climax engine in a contest was a Kieft with a 1097cc FWA. The match being the 24 hours of Le Mans in 1954. The Kieft did not finish as its rear axle broke.

The season of 1954 saw Coventry Climax-powered cars winning races. The company found themselves in a monopoly situation. Competition mostly used much modified Ford and MG units that were expensive and unreliable. Leonard Lee did not sell any specials to anyone, not even the persuasive Colin Chapman of Lotus.  Everyone was given an identical engine. And development marched on. Compression ratio was increased and later on so many changes were made that it was called the Mark II.

The absolute capacity limit for the block was represented by the FWB, of which only a few were made. These engines, that contained nearly 1500cc, were raced in 1956 by Coopers. And it was one of these cars that won the British Grand Prix of that year.

When Colin Chapman started thinking up the Elite in 1957, Coventry Climax agreed to provide the engines. But only if they could be guaranteed a minimum order of 1000 units. The Feather Weight Elite (FWE) was produced from 1959 to 1963. It had a relatively unstressed output of 72bhp. The Lotus 14 (Elite) was winner of its class at Le Mans on 6 consecutive years from 1959 to 1964. These engines were also sold to Jack Brabham who fitted them (as after-market extras) to sports cars of the day.

This is a 1,100 cc FWA version of the motor as fitted to the Lotus Eleven and Lotus Six on display in the Museum. The Elite has a 1220 version of the motor.

Racing Results

Results in 1965-66
World Championship 1965

Lotus MK VI l Lotus Eleven l Lotus Elite l Amilcar l Coventry Climax l Zeta l Scootamota l Ransomes MG6