Engine Lubrication: Description and Operation

The engine lubrication system is of the force-feed type in which oil is supplied under pressure to the crankshaft, connecting rods, camshaft bearing surfaces, valve lifters and timing chain hydraulic tensioner. All other moving parts are lubricated by gravity flow or splash.

Oil enters the gerotor type oil pump through a fixed inlet screen. The oil pump is gear driven by the crankshaft. The oil pump body and gear cover are cast aluminum, and the gerotor gears and cover are steel. The oil pump driven gear is phenolic.

The pressurized oil from the pump passes through the oil filter located on the left (front) side of the engine block. A by-pass valve in the engine block allows continuous oil flow in case the oil filter should be restricted.

Oil then enters the gallery where it is distributed to the crankshaft and timing chain hydraulic tensioner.

The connecting rod bearings are oiled by constant oil flow passages through the crankshaft connecting the main journals to the rod journals. A groove around each main bearing furnishes oil to the drilled crankshaft passages. An oil cooling hole (IOA), which indexes once each revolution with the connecting rod oil feed hole, is drilled in the connecting rod for piston cooling.

The pressurized oil then passes through the oil flow check valve into the cylinder head and then into each camshaft housing. Cast passages feed each valve lifter and drilled passages feed each camshaft bearing surface.

An engine oil pressure switch or sensor is installed at the end of the exhaust camshaft housing oil galley.

Oil returns to the oil pan through passages cast into the camshaft housings and cylinder head. The timing chain housing drains ddirectly into the oil pan.