Coventry Climax Engines Ltd.

A Coventry Climax H30 Two-Stroke Diesel Engine

Coventry Climax FWMB  sohc Petrol Engine on Test

The Beginnings
The firm of Coventry Climax Ltd. was founded in 1903 as Lee Stroyer by Mr Stroyer and Mr. H. Pelham Lee, both former Daimler employees. In 1905 with the departure of Stroyer, Mr Lee who (like Frederick Simms - also connected with Daimler) had seen an opening in the market for an independent specialist engine manufacturer, renamed the firm Coventry-Simplex and moved to Payne's Lane Coventry. He realised that the new age of the motor car had arrived; new 'horseless' or 'motorised' carriage makers were springing up and there could possibly be a demand for a supplier of a suitable proprietary engine to allow manufacturers to concentrate on chassis design. The business flourished, again moved to Friar's Road, Coventry and continued until the depression of the 1930's which saw the demise of many small car manufacturers. This left the company with a small stock of surplus engines, especially those for Swift cars which had recently gone into liquidation.

 By this time, Mr. Lee had passed the business on to his son, Leonard, who made the wise decision to utilise these engines, (by now called Coventry Climax following a change of address to East St, Coventry) firstly, in stationary generating sets using for example the 800cc sidevalve SM series (Swift Motors)  producing barely 20bhp and, just before the second World War, in fire-pumps to meet a government requirement. Entering the field of fire-pumping equipment in 1937 was opportune indeed for Coventry Climax and the advent of the Second World War, plus technology gained with the Godiva range of trailer-mounted and portable pumping units set the company in good stead for the future. The engines proved their reliability for continuous running under power for long periods due to their good design and build quality. The company aquired the former Riley Motors factory in Widdrington Road during the late 1930s.

Many different engine types were built over the years, both petrol and diesel. One of the earliest designed Coventry-Simplex engines gained acclaim when it was used to power Sir. Ernest Shackleton's 1914 Antarctic Expedition tractors. Coventry Climax was responsible for the design and manufacture of engines for such notable pre-war automotive marques as Triumph, Morgan, Marendaz, Clyno, Crossley, Swift, Standard etc. After the war the engines became famous for powering Kieft, Lotus, Cooper, TVR, and even one or two development Austin Healey Sprites and Triumph Heralds.

Departure from automotive
Engines in the standard range had also been developed over the years into those suitable for more specialist purposes, for Admiralty launches, lifeboats, and diesels for narrow-gauge locomotives in underground mines where conditions made spark ignition dangerous. A two-cylinder diesel was fitted into the Bristol Crawler tractor which had been taken over by Jowett and replaced a petrol engine sadly lacking in power. In 1949, an advanced two-stroke diesel was announced which powered a naval launch having a greater turn of speed than any other at that time. This 1789cc engine, designated the KF4, was developed at the Mile Lane works, Coventry, and incorporated the Kadenacy Patented scavenge system licenced from Armstrong Whitworth Ltd and with Roots-type blower, stayed in production for the Admiralty until 1955.
After the war, a large range of diesel fork-lift trucks was developed and produced. They were designed and built entirely 'in-house' and became well known as the 'All British Fork-lift Truck. A good example of 'create a product and supply another to fit it!'

Better Fire Pumps
The next attempt at fire-pump design resulted in an outfit which pumped water at twice the rate for half the weight of any other at that time. This came about because in 1950, the company took on an ex-Bentley and Jaguar engineer, Walter Hassan who, with Harry Munday, greatly influenced the development of these engines. The new 4-cylinder engine, developed in just seven months, was 1020cc, produced 38bhp and was designated the FW for FeatherWeight. Immediately it won a huge Home Office contract to supply fire pumps.  Coventry Climax became a household name after the motor racing fraternity saw the advanced design of an all-alloy, free revving, OHC fire pump engine as potential for a racing engine.  The engine had not been developed with racing in mind as its capacity of 1020cc     was awkward in respect of the racing formulae so in 1953 a new version the FWA (A for automobile) was announced with uprated crankshaft, special pistons, better breathing and higher compression ratio. This produced an amazing 72bhp at 6100 1954. It was enlarged to 1500cc as the FWB but only 35 were produced for racing cars. This engine was then fitted to an even better firepump, giving a tremendous output of water, and called the FWBP of which 700 were produced.  Later on in V8 form, the same basic design took on the rest of the world to dominate the Grand Prix and Club racing scene for over a decade. At this time too, the FWC, a special of 750cc was built specially for racing in USA, the car achieved success in the hands of Dan Gurney.

Success with "The Fire Pump engine that wins Races" as the company's advertising stated, led on to the famous series of purpose built Formula One engine designated FP series ( FirePump?!) starting at the FPE of upto 200bhp and leading on to the FPF, best known in the Cooper cars.

The FW Range and derivatives
The FW range became marinised as the FWM ( Featherweight Marine) and was very successful in this new role. Its development in this form was the last series of actual fire pump engines and was about 1400cc. A version of the smallest engine in the model range, the 750cc FWMB, was adapted (cheapened!) to suit the automotive industry's requirements in collaboration with the Rootes group, also based in Coventry. This engine, known at the time as the FWMA ( A for automotive)  was to be fitted to the new Hillman Imp (although termed at the time 'Ajax project'), being built at the all-new and disastrously planned Linwood plant in Scotland. This was the company's last purely automotive venture. The engine suffered from under-development and despite constant upgrading was always beset by overheating and cooling problems.
Interestingly the 750cc FWMB was at this time producing the same power output as the original 1020 FW engine had and it had also shed some weight, now having the ability to be carried by two men rather than the four required for the FW.  The FWMD was also experimented with as a diesel version, basis for the world's first diesel outboard motor, whilst the FWMC was used in a Lotus racing car with many special revisions and an entirely different cylinder head.

More Specialised Diesels - The H30
The  Ministry of Defence contract experience gained from the success of the KF4 diesel led on to the design and production of the very different H30 900cc two-stroke diesel exclusively for the MOD. The actual design was originally contracted to Armstrong Whitworth, probably because of that company's experience with vertically opposed piston two-stroke engines which it, in turn, licenced from Junkers who was the patentee. The supercharged engine was to be of multi-fuel capability for the auxiliary engine in the then-new generation of main battle tanks to be known as Chieftain. The fuel range was loosely described as 'anything from premium petrol to diesel' with varied and stringent parameters of performance, reliability, lightweight, minimal and simple maintenance, and certain cold starting down to -40 degrees C. The H30 has been used by Armed Forces throughout the world, by Royal Ordnance plc, and British Aerospace plc. It can be found in both the towed and tracked Rapier missile systems, the Khalid MBT's and the Challenger tank.  An example of this rare and interesting little engine can be seen at Internal Fire Museum of Power in West Wales.

.....and along came the dreaded Leyland!
In 1963, Coventry Climax Ltd. was taken over by Jaguar Cars for its expertise in Ohc engines. In doing so, the company regained Walter Hassan back into the fold. Five years later, in 1968, Jaguar was taken over by British Leyland, (a certain death warrant for many a good company,) so Coventry Climax became just part of the Special Products Division along with Alvis and Aveling-Barford, etc with special emphasis on fighting vehicles. In 1970, the firepump business was sold off to become the Godiva Fire Pumps and moved to Warwick. The early 1980's saw more changes; the fork lift business was sold to  Coventry Climax Holdings following a merger with Conveyancer, it later became British Fork Truck Holdings, a consortium run by Emmanuel Kay and Lansing Bagnall Ltd. In 1986, Coventry Climax again went into receivership but was rescued by Cronin Tubular. Finally, the Coventry factory was closed, the buildings in Mill Lane and the test shop in Widdrington Road which used to echo to the drone of many fine engines fell silent, lay empty and became derelict.

'And so to Bath'  - briefly
Due to the commitment to the Ministry of Defence, in 1990 the engine side of the business was sold to Horstman Defence Systems of Bath, Somerset, for the servicing, repair and possible manufacture of both the H30 diesel and FWMB ohc petrol engines. Horstman (formerly Horstmann, but the second 'n' was dropped at the outbreak of the Great War as it inspired German associations) was an old established business having produced interesting quality sporting cars with innovative designs from early in the twentieth century. A family association with R.A. Lister resulted in many Dursley-made castings for the firm.
Ironically it is perhaps interesting to note that Horstman, in 1923 during its heyday of car building, was the first British manufacturer to offer an engine with a supercharger. Now, over eighty years on, it was possibly the last British manufacturer to still do so with the H30!
However even HDS was not immune to change and the engine work has now been abandoned.

©Eric Brain 1994 (With acknowledgments to John Ridd - ex Coventry Climax - and Phil.Caudle of H.D.S.)

Updated March 5th 2010©


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The Imp Site - Coventry Climax   This is a very good site, well worth a visit