M20 Low Compression 2.7 Stroker Engine

Build sheet


Owner                 Nick

head                    731 with 42mm intake valves fitted (std 885 head) and Rhd porting

Cam                     custom low comp grind 272 duration 11mm lift

Bottom end         Stock low compression eta 2.7, 135mm rods, 8.5:1 pistons

Intake                  RHD ITB's

Exhaust               Generic production headers


This is a popular low cost BMW stroker option performed by taking an  ETA 2.7L bottom end and fitting a 323i 731 option cylinder head. These components are a compatible direct bolt on fit.

This engine had already been built by others.  Internal components were completely stock however it had a large 290 degree cam which was not compatible with an engine that only has around 8.5-9 : 1 compression. Externally the engine was fitted with extractors, an aftermarket ecu and a cold air intake. Power was a disappointing 123rwKw


Build job was to fit some stock 325i 42mm intake valves and do some basic head porting. Then reassemble with a smaller 272 degree camshaft and fit a set of RHD ITB's

Power gain was 25rwKw up to a healthy 148.4rwKw (198rwHp) remember this is a very low compression engine, the improvement to the mid range torque was most significant making this a very strong engine both on the road and on the track.


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