Forced lubrication

Forced lubrication supplies oil under pressure from an engine-driven or electric pump to every bearing, the piston cooling jets, and the crosshead guides, instead of relying on splash or ring feed. A gear pump draws from the sump or a separate tank, passes the oil through a cooler and a duplex filter, then distributes it through drilled galleries at a regulated pressure, commonly 3 to 5 bar for the main system and higher for crosshead pins. Flow carries away bearing heat and flushes wear debris to the filter. Loss of pressure trips the engine, since a starved main bearing wipes its whitemetal within seconds at full load.