Austin D-Series engine

The Austin D and K series engines are a straight-six engine made by the British Austin Motor Company between 1939 and 1968. It was developed initially for the lorry market; but was used in a number of automobiles in its later life. It was an overhead valve non-crossflow cylinder head design. Both block and head were made out of cast iron. All engines had a forged four main bearing crankshaft.^[1]

The engine was developed under the close watch of Austin chief Leonard Lord. The design was inspired by the Chevrolet Stovebolt engine which was an inline six cylinder engine that was used by General Motors British subsidiary Bedford Vehicles. In the late 1930s, when rival Austin decided to get into the 2-3 ton payload lorry market and in a crash development programme based the design on the basic architecture of this "Stove Bolt" engine. Austin however made detail improvements to the Chevrolet design. Austin's engineers added detachable shell main and connecting rod bearings and pressurized lubrication. The initial design had a engine displacement of 3460 cc. During the Second World War, Austin increased the bore and stroke to enlarge it into a 3995 cc engine which produced 87 bhp (65 kW). The larger engine was put in military trucks beginning in 1940. Both engine sizes were in production after the war. When the carburettor was changed from Zenith to Stromberg, it produced 100 bhp (75 kW).

Truck engines had K designations and car engines had D designations.^[2]