The BMW M328 is an overhead valve straight-six petrol engine which was produced from 1936 to 1940. It was a high-performance development of the
BMW M78
The BMW M78 is an overhead valve straight-six petrol engine which was produced from 1933 to 1950. It is the first straight-6 automobile engine produced by BMW, an engine layout which has been a key feature of the brand for many years since.
The M ...
engine that was produced alongside the M78.
Compared with the M78, the M328 has an aluminium
cross-flow cylinder head with
hemispherical combustion chamber
A hemispherical combustion chamber is a type of combustion chamber in a reciprocating internal combustion engine with a domed cylinder head notionally in the approximate shape of a hemisphere (in reality usually a spheric section thereof). An en ...
s.
The M328 was used in the
BMW 328 and
BMW 327/28 coupes.
After World War II the engine was also licensed to
Bristol Cars in the United Kingdom.
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Design
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.
This results in a valve layout similar to a
DOHC
An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion cha ...
engine.
With a bore of and a stroke of , the displacement was , the same as its M78 predecessor. Fuel supply was via three
Solex "30 JF downdraft" carburetors.
The M328 engine has a compression ratio of 7.5:1 and produces at 5000 rpm.
Versions
Applications:
* 1936-1940
328
* 1937-1940
327/28
See also
*
BMW
*
List of BMW engines
BMW has been producing engines for automobiles, motorcycles and aircraft since 1917, when the company began production of an inline-six aircraft engine. They have been producing automobile engines since 1933.
Motorcycle engines
Automotive ...
References
{{BMW_automotive_petrol_engines:_1920s_to_1940s
M328
Straight-six engines
Gasoline engines by model