BMW S58 Owner's Handbook Manual page 30

S58￿Engine
4.￿Engine￿Mechanical
S58￿engine,￿crankshaft
Index

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2
3
Crankshaft￿main￿bearing
The￿crankshaft￿main￿bearings￿are￿adapted￿to￿the￿S58￿engine.￿Adaptations￿were￿necessary￿in￿order
to￿satisfy￿the￿higher￿demands￿of￿the￿high-revving￿design.￿The￿bearings￿are￿a￿lead-free￿design.￿The
material￿combination￿for￿the￿lower￿bearing￿shells￿takes￿the￿form￿of￿a￿Federal￿Mogul￿G488.￿For￿the
upper￿bearing￿shells￿a￿Federal￿Mogul￿G490￿is￿used.￿The￿thrust￿bearing￿is￿located￿at￿the￿4th￿bearing
position.
When￿replacing￿the￿crankshaft￿main￿bearings,￿the￿bearing￿shell￿classification￿must￿be￿taken￿into
account.￿The￿precise￿procedure￿for￿replacing￿the￿crankshaft￿main￿bearing￿shells￿can￿be￿found￿in￿the
up-to-date￿information￿in￿the￿BMW￿workshop￿system￿ISTA.
4.2.2.￿Connecting￿rod￿with￿bearing
The￿forged￿connecting￿rod￿of￿the￿S58￿engine￿has￿a￿nominal￿length￿of￿151.1 mm.￿The￿connecting
rod￿is￿a￿carry-over￿part￿from￿the￿S63B44T4￿engine.￿As￿with￿other￿BMW￿engines,￿the￿small￿end￿has￿a
profiled￿bore.￿The￿force￿acting￿from￿the￿piston￿via￿the￿wrist￿pin￿is￿optimally￿distributed￿to￿the￿bushing
surface￿by￿this￿shaped￿bore￿and￿the￿edge￿load.
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Explanation
Main￿bearing
Drive￿for￿oil￿pump￿and￿valve￿gear
Connecting￿rod￿bearing