After having made a pencil drawing of the Jaguar XK engine, we got more and more carried away so to speak, and decided to start with a series of famous racing engines, which made automotive history. Of course, we continued first with the D-type theme, as we felt it deserved further attention.

So here it is…

Engine capacity of this XK engine in this racing version is still the original 3442 cc, with also the original bore and stroke dimensions of 83 x 106 mm.

With triple Weber carburetors and a 1:9 compression ratio it developed 253 PS or 186 kW at 6000 rpm. Torque was very impressive for a normally aspirated engine, being 328 Nm at 4000 rpm.

It had dry sump lubrication, as the superb roadholding  of the D-type triggered G forces which would let the engine starve for oil had the original sump been retained. It also allowed a larger oil quantity, lowering oil temperature on the grueling long Mulsanne straight at Le Mans, where the D-type would run at speeds in excess of 170 mph, or 270 km/h. There was also another practical reason, which might have been even more important: the D-type is very low, so to reduce the engine height, a dry sump layout was chosen.

The D-type itself was structurally designed by Jaguar’s William Heynes Technical Director and Chief Engineer. It applied aeronautical technology. The cockpit section was of monocoque construction, mostly comprising sheets of aluminum alloy. It was about five years later that John Cooper started to use the same concept for his Formula 1 cars…

The aerodynamic bodywork was largely the work of Malcolm Sayer, who had joined Jaguar following a stint with the Bristol Aeroplane Company during the Second World War and later worked on the C-Type. The D-Type required a minimal frontal area. To further reduce the XK engine’s height, the engine was canted at 8½° from the vertical, which made the typical offset bonnet bulge necessary.  It might also have been needed, according to Philip Porter, in his book Jaguar Sports Racing Cars, to provide extra space for the ram pipes feeding the three twin-choke Weber carburetors….

You can see clearly in the drawing the rampipes of the Webers, and the fact that the engine is canted…

Just enjoy the drawing. The next one will be the famous Auto Union V16 engine…

Hans Knol ten Bensel