BMW M328

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BMW M328
BMW 328 6-Zylinder-Motor.jpg
Manufacturer BMW
Production 1936-1940
Configuration OHV straight-6
Predecessor BMW M78
Successor BMW M335

The BMW M328 is a straight-6 OHV petrol engine which was produced from 1936 to 1940. It was a high-performance development of the M78 engine that was produced alongside the M78.[1]

Compared with the M78, the M328 has an aluminium cylinder head[2] with a hemispherical cross-flow combustion chamber.[3]

The M328 was used in the 328 and 327/28 coupes.[4]

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


The M328 had an unusual valvetrain design. While the camshaft was located in the block (as per OHV engines), the exhaust valves were controlled by a transverse pushrod from the intake valves.[3] This meant the valve layout is similar to a DOHC engine.

With a bore of 66 mm (2.6 in) and a stroke of 96 mm (3.8 in), the displacement was 1,971 cc (120 cu in), the same as its M78 predecessor. Three Solex "30 JF downdraft" carburetors were used on the M328.[3]

The M328 engine has a compression ratio of 7.5:1 and produces 80 PS (59 kW) at 5000 rpm.[3][5]


Model Displacement Power Torque Years
M328 1,971 cc (120 cu in) 59 kW (79 bhp)
@ 5000 rpm
126 N⋅m (93 lb⋅ft)
@ 4000 rpm



  1. ^ "BMW World - 6-Cylinder Engines". Archived from the original on 13 September 2010. 
  2. ^ "1937 BMW 328". Retrieved 23 August 2017. 
  3. ^ a b c d "BMW 328 - the legendary roadster". Archived from the original on 3 October 2010. 
  4. ^ Norbye, Jan P. (1984). BMW - Bavaria's Driving Machines. Skokie, IL: Publications International. ISBN 0-517-42464-9. 
  5. ^ "1937 BMW 328". Retrieved 24 August 2017.