Crankshaft: Description and Operation

Crankshaft Assembly



the MINI COOPER crankshaft is machined from nodular cast iron. the MINI COOPER S crankshaft is machined from forged steel. Both crankshafts provide a mounting point for the crankshaft sensor reluctor ring that is retained by three bolts. the drive for the oil pump is provided by machined flats towards the front of the crankshaft. the auxiliary drive belt pulley is a press fit on the crankshaft and retained by a bolt.

Crankshaft Bearings
All MINI COOPER engines use five main bearings. Lubrication is supplied through holes in the upper shell directly from the main oil gallery. the upper shell is grooved to transport oil to the lower plain shells located in the bearing ladder. A thrust washer built into the center upper main bearing shell controls crankshaft end float. the connecting rod and main bearing shells are made of an aluminum base that is rolled onto a low carbon steel backing.