Oil pressure

Oil pressure is an important factor in the longevity of most internal combustion engines.

Other components such as cam lobes and cylinder walls are lubricated by oil jets.

Sufficient oil pressure ensures that the metal of the rotating shaft (journal) and the bearing shell can never touch, and wear is therefore confined to initial start-up and shutdown.

The oil pressure, combined with the rotation of the shaft, also hydrodynamically centers the journal in its shell and cools the bearings.

Examples of such restrictions include big end and main bearings, as well as camshaft and rocker gear if fitted.