The BMW M328 is an overhead valve straight-six petrol internal combustion engine which was produced from 1936 to 1940. It was a high-performance development of the BMW M78 engine that was produced alongside the M78.^[1][2][3]

Compared with the M78, the M328 has an aluminium cross-flow cylinder head^[4] with hemispherical combustion chambers.^[5]

The M328 was used in the BMW 328 and BMW 327/28 coupes.^[2][3][6]

After World War II the engine was also licensed to Bristol Cars in the United Kingdom.

The M328 had an unusual valvetrain design; although the camshaft is located in the engine block, the exhaust valves are actuated by a transverse pushrod from the intake valves.^[5] This results in a valve layout similar to a DOHC engine.

With a bore of 66 mm (2.60 in) and a stroke of 96 mm (3.78 in), the displacement was 1,971 cc (120.3 cu in), the same as its M78 predecessor. Fuel supply was via three Solex "30 JF downdraft" carburetors.^[5]

The M328 engine has a compression ratio of 7.5:1 and produces 59 kW (79 bhp) at 5000 rpm.^[5][7]

Applications:

• 1936-1940 328
• 1937-1940 327/28

• BMW
• List of BMW engines