Military V8 Engine 1953 – 1957

Jaguar 9-litre military V8 engine.

When Jaguar announced the XK8 in 1996 it was powered by Jaguar’s first production V8 engine, the new AJV8, but forty years earlier the Company had produced a V8 engine in response to a request from the British Army.

From 1952 to 1953 Jaguar manufactured spares for Meteor Mk IVB engines including crankshafts – and assembled and tested 150 engines for the Ministry of Supply.  The Meteor was a version of the Rolls-Royce Merlin aircraft engine that had been modified for use in main battle tanks.

Rolls-Royce Meteor tank engine
an adaptation of the famous Merlin aircraft engine.

William Lyons contacted the Ministry of Supply in December 1950 enquiring about vehicle or engine contracts for the military and soon after the move to Browns Lane from Foleshill his letter bore fruit.  In 1952 Jaguar secured a contract to set up a production line to manufacture Meteor spares and build Meteor Mk IVB engines.  The Meteor was a version of the Rolls-Royce Merlin aircraft engine that had been modified for use in main battle tanks.  Jaguar manufactured 150 sets of spares – which included crankshafts – and 150 engines were assembled and tested.  Gerry Beddoes,  then working in the Service department and later to become one of Jaguar’s top engineers, recalled that during his tour of manufacturing he spent three months with machine setter Jack Bedder “…taking two forgings down the crankshaft line, setting up each machine in turn.  The machines were partly new but mostly from government stores.  Machines were also set up for heads and crankcase, they were Huller machines from Germany; all Meteor work ceased in 1953.”  Once the engines had been delivered the production line was shut down, the tooling and equipment removed from the Jaguar works and stored, ready to be used in the future if required.   The Ministry of Supply were pleased with Jaguar’s work with the Meteor and it followed that, when they wanted a new engine, they turned to the company that had also produced a military XK engine which had passed the stringent tests at the Ministry of Supply’s Fighting Vehicles Research Design Establishment (FVRDE) at Chobham in Surrey.

In March 1951 two members from the FVRDE at Chobham in Surrey visited Jaguar at Foleshill.  They met with William Lyons, William Heynes and others to discuss the possibility of a purpose-built 8-litre V8 engine for use by the British Military.  The talks were positive and the two men from the FVRDE went away to draft a preliminary specification of the proposed engine.  The Chief Engineer (Power Plant) from the FVRDE, Mr W J Semmons, wrote to William Lyons on 15 March 1951, enclosing a rough specification for the proposed engine.

Semmons wrote: ‘We think this [the enclosure] should be sufficient to enable you to prepare an estimate of the cost of the necessary design work and the manufacture of, say, 12 prototype units.

‘We suggest, however, that before submitting an estimate you should thoroughly examine the specification and then come along here for further discussion on the numerous points which are certain to require clarification.  At the same time, we would like to discuss with you one or two possible alternative suggestions for the design of other types of engines, either instead of, or in addition to the engine now under consideration.’

Unfortunately, the enclosure with the FVRDE specification does not appear to have survived in the Jaguar archives but we do know that Lyons handed the project to William Heynes and the engineering department.

A photograph taken at Browns Lane showing the
Jaguar 9-litre V8 seen from the rear right;
fitted with Solex carburettors.

A memo to Heynes from Lyons, dated 30 March 1951, states:

‘I have had a look through the preliminary specification which has been drawn up by the Ministry of Supply.  This specification is considerably at variance with the one we have put forward where they ask for an 8 cylinder vee engine of approximately 8 litres.  This puts rather a different aspect on the subject, but should not necessarily be a deterrent for going forward with the scheme.

‘I will have a scheme prepared on this basis, but before we go too far with design work I feel it is essential that we should go down there and discuss the whole thing with them, examine engines which are doing similar work and find out generally the shape of the power curve necessary for the purpose.

‘Mr. Semmons suggests this in his letter and I think it is only a matter of fixing a suitable date with them.  I would like at least a week or ten days’ notice so that I can get an outline prepared as a basis for discussion.’

While the discussions were in progress, a 3.4-litre XK engine was fitted with a military carburettor and air cleaner along with a lorry exhaust system and bench tested in the Experimental department.  This was despatched to the FVRDE at Chobham where it was installed in a standard Army Bedford lorry.  Gerry Beddoes remembered the engine.  “During my first eight months at Jaguar when I worked for Jack [John] Emmerson on engine development, I assisted with the tuning of this engine and the preparation of performance data before it was sent off to Chobham.”

Following the request from Chobham, Jaguar prepared and submitted a specification to the FVRDE titled:  ‘Proposed Preliminary Specification for 8 Litre Vee 8 Engine (Carburetted, Petrol)’ which dealt with fuel, cooling, lubrication systems along with overall details of the unit.

Under the General heading we can read that the specification ‘…is compiled to provide a basis for quotation, and technical discussion.  A more detailed specification will be provided later.  The engine is primarily for installation in Fighting Vehicles but may be required in other Service equipment.  The swept volume of the engine shall be approximately 1 litre per cylinder and the bore and stroke shall be approximately equal.  A bore of 108 mm and stroke of 110 mm is suggested as a basis for initial design investigation, but these dimensions may be varied slightly to suit existing or available tooling.

‘It is intended that the design shall be capable of expansion to a 12 cylinder vee form or an “in line” 6 cylinder form should a requirement arise.  In this event, a maximum degree of interchangeabiliy of parts is required.

‘A power output, in the vee 8 form, of 300 B.H.P. at 4,000 r.p.m. is required at the outset and powers proportional to the number of cylinders will be required in the other sizes of engine.  Valve proportions and porting shall be such that an increase in this power may be expected in the course of engine development, particularly an increase in B.M.E.P. in the mid speed range.  The crankcase shall be rigidly constructed in monobloc form, capable of unit construction with a gearbox if so desired.’

From the above, we can see that discussions so far had extended to a possible family of engines which could have been applied to a variety of military requirements.  Apart from the tank engine, an armoured car, lorry and even a marine variant could have been developed.

The 9-litre V8 engine seen from the rear left.
The resemblance of the heads and cam covers to those of the XK engine is very clear.

Gerry Beddoes: “There were four of us working on the V8; Bill Heywood became section leader, also Alec Forbes, Arthur Firbank and myself.  There were monthly progress meetings with engineers from the FVRDE named Tafft and Semmonds.” Tafft had been one of the two engineers who had made the initial visit to Foleshill in March 1951; the other engineer was named Daniel.  It was Gerry’s task to design the balance weight for the crankshaft so that the crankcase dimensions could be determined.  “To do this,” says Beddoes, “I needed to know the weight of the piston and connecting rod.  Brico gave me their estimate for the piston and I drew the connecting rod and calculated its weight.  Dimensions were finished and Alec Forbes drew the integrated block and crankcase, a mammoth task running to, I think, eight large drawing sheets.  For the time the engine was very advanced with four valves per cylinder, twin overhead camshafts in each cylinder head driven by gears and an enclosed ignition system to permit immersion.  I made calculations for everything bearing loads, flywheel size, gear train for power take-off, generator and camshaft drive, and for cylinder head and piston crown to achieve the correct compression ratio.  A full V8 distributor would have been too large in diameter, so twin four cylinder units were employed, gear driven at the front of the Vee and totally encased in an aluminium cover so that the engine was fully waterproof.”

Rear view of the Jaguar 9-litre V8 shows the clutch and flywheel; the twin-choke Solex carburettors and inlet manifold are clearly visible.

Design work – which included input from Jaguar engineers like William Heynes and Claude Baily – on the engine continued through 1953 and into 1954 with the first components being machined in June 1954.  Beddoes found that “… both the piston and connecting rod were overweight; in the case of the connecting rod due to the dies not fully closing in the forging.”  Gerry remembered that the military engine “…used overhead camshaft heads with a valve gear derived from the XK engine and standard XK tappets operating parallel valves in a pent roof chamber with radiused ends.  I remember it well, as I had to calculate the volume and that of the piston crown to establish the compression ratio.  A male model of the chamber was made of wood and used to copy mill a block of aluminium to make a final check.  The first engine ran with about 15 per cent underbalance and there was much concern over bearing loads and vibration.”

This first engine was running by mid-January 1955 and only two small snags were experienced, one was the Hobourn Eaton oil pump which could suck through the release valve and the other was a high-pitched whine that was traced to the exhaust cam running dry.  They were simple problems and quickly addressed to continue with the engine tests.  Early on in the design process twin-choke downdraft Zenith carburettors were selected and fitted to the unit as it was in-build, but the setup proved too tall and the Lucas mechanical fuel injection was chosen.  However, this system, although   fitted to the initial engine, required more work and later examples of the V8 unit were fitted with lower profile Solex carburettors.  Following trials by Jaguar at Browns Lane, two examples were shipped to the Ministry of Supply for the Army to carry out their own trials.


In September 1954, Ernest Rankin, Public Relations Officer at Jaguar Cars, issued a Press Release:

Jaguar Engines for Tanks.

‘From racetrack cars to armoured fighting vehicles is a far cry, but in the 9-litre Jaguar engine shown for the first time at the Fighting Vehicles Research & Development Establishment at Chobham, some affinity can be seen between the famous 3 ½ -litre Jaguar XK engine of Le Mans renown and this new powerful unit of 9,029 cc.

‘The 9-litre Jaguar engine, which has been designed by the Jaguar technical development division for the Ministry of Supply, is a V8, normally aspirated petrol engine with a bore and stroke of 114.3 mm  x 110 mm.  With cylinders set at 90 degrees, and develops 320 brake horsepower at 3,750 r.p.m.’

By 1980 the Jaguar 9-litre V8 had been restored, repainted, given two twin-choke Holley carburettors and used in tractor-pulling competitions.

The release goes on to add that there are other possible applications for the engine but stops short of any details of the trials that had been carried out by Jaguar and the Army.  Records are sketchy but it would appear that five or six 9-litre V8 engines were built and all were despatched to the FVRDE as there is no mention of a unit surviving at Browns Lane.  In the event, trials appear to have ceased by the end of 1956 or early 1957 and the Ministry of Supply did not proceed with an order from Jaguar for the engine to be put into production.  The units that had been delivered languished at Chobham until being sold off as surplus.

One complete engine is known to have survived, as it was discovered in the 1970s at an ex-military scrapyard and purchased by two tractor-pulling enthusiasts who rebuilt it for fitting into their competition vehicle.

This remarkable Jaguar V8 engine was in evidence throughout the 1980s and into the early 1990s but has now been retired.  Its present whereabouts is unknown to the writer who would be delighted to hear news about it.

Author: François Prins

© Text and Images – Jaguar Daimler Heritage Trust