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.

[2][3][6] After World War II the engine was also licensed to Bristol Cars in the United Kingdom.

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