A VISIT TO COVENTRY - CLIMAX

A VISIT TO COVENTRY-CLIMAX

K of the oinst:iiidim leatures of last season’s tumor racing. so far as this eountry was concerned. Win., the excellent performance of small sports cars powered with the 1.100-e,c. Coventry-Climax EWA engine..

This engine. has been described itt MoTott SPORT and its performance when installed in the Mk. IX Lotus forms a leading article in this issue, but so much interest centres around it, and its future development, that we paid a visit to Coventry to discuss the subject. with Mr. Densham. of Coventry-Climax Engines Ltd., himself a motoring enthusiast of long standing, who used to oi,n cc 1931 Frazer-Nash Interceptor.

They have every reason to be proud a ilie 1.Ar A .0. Coventry. for amongst the sports-car lap records non held hy cars so powered are those for Goodwood (I,I00-c.c. class (:hapman-Lot us).

stone (1,500-ex. classBueb-Cooper), Crystal Palace (2,00(l-c.c. class— Bluth-Cooper). Brands Hatch (unlimited class (:hapmanLotus), Davidstowe (I,500-c.c. class—Brandon-Halsey lee). Snetterton (1,100-e.c. class–Chapman-Lotus), Castle Conda• (2,000-c.e. class-Bueb-Cooper): in addition to which there was Chapmait’s memorable. performanee in the T.T. and Sepwith’s Cooper’s altsiditte sports-car course record at Prescott. For an undeveloped I.Inu-e.e. class engine to take lap records in higher cat arit y eiasses, even absolute lap reeortls. is creditable indeed ! Morett■ cr. in 1051 a Kieft-Climax won the 1.1110-c.c. class of the Duedrod T.T. and last year Climax-powered ears finished 1, 2, 3 in this el.-c-.

The story of how the I.-4VA came into being is not only interesting, but answers those who maintain that it is really an industrial unit.

Before the Hitler War Coventry-Climax went well known as manufacturers of proprietary motor-car engines. Amongst their early efforts can be numbered the engines for 11.9 Clyno, A.J.S., Swift Cadet and Marendaz-Speeial. Later came the famous four and six-cylinder i.o.e. engines which Triumph made under licence and similar power units which Coventry-Climax made for Crossley. Up to 1937 they manufactured the engine for the Morgan 4/4, while. other notable contributions to competition were the three supercharged engines for the 11-litre Vale Specials, of which Ian Connell’s was raced at Brooklands and Dottington, the others going to Ireland. In addition, this company built the engine for the Lagonda Rapier and later Rapier, although the design in this ease was that of Mrs. Ashcroft, of the Lagonda Company.

The monopolies which swept through the motor industry just before the war reduced the demand for proprietary car engines, so Coventry-Climax sensibly turned to stationary generator sets and engines for troller fire pumps, later introducing a useful range of diesel engines.

To conform to a Government specification calling for a light fire pump able to be carried by two men and capable of delivering 350 gallons of water per minute, Harry Mundy designed an entirely new Coventry-Climax unit. the MP (Feather-Weight Pump). The required low weight was achieved by using a 1,020-c.e. unit of light alloy throughout, and the necessary power by making this little unit run at high crankshaft speed. To this end dimensions of 2 in. by 21 in. bore and stroke were employed to limit piston speed. while a rigid, counterbalanced three-bearing crankshaft and a gear-enmduplex-ehain-driven single o.h. camshaft operating valves in a squish-type combustion chamber direct through piston-type tappets, enabled high r.p.m. to be achieved. with a minimum of wearing faces in the valve gear. Three prototype FW engines were built and 37 b.h.p. was achieved at 3.500 r.p.m. on one .carburetter. Coventry-Climax duly obtained the contract to build this excellent little engine and its companion light-alloy pump in quantity, which they did after devoting a year to its development. The entire pump unit weighed 310 lb.

At the time Mundy had the idea of sports-car racing in mind and during•the third production year an automotive version is as deSigned -the now famous FANYA. The bore was increased to 2.58 in., to give a capacity of 1,097 c.c.. the dhnensions thus being over-square. ic.. 72.4 by 66.6 mm. The diameter of both inlet and exhaust valves was increased and double of the industrial engine was changed for a coil distributor, to save same crankshaft was used, hut it is of forged steel instead of cast iron, rings were fitted. the valve ports were opened up slightly, the t.he machining being carried out by Laystall. Dykes-type piSton instead of single Valve springs were used. The vertical magneto

weight and to ease the load nc the driving gears when savage fluctuations in engine speed occur. as when gear-ehanges are made towards the limit of the r.p.m. range.