Engine Lubrication: Description and Operation

Lubricating System




The engine lubricating system has forced-flow lubrication, with the oil pressure being generated by an internal gear pump consisting of a pinion and an eccentric ring gear. The pump, located in the oil pump housing, is driven by the crankshaft.

Oil is drawn from the oil pan to the oil pump via an inlet strainer and pipe. A relief valve in the oil pump housing limits the oil pressure and returns surplus oil to the inlet side of the pump. The relief valve is controlled by cooled and filtered oil. From the pump the oil flows through the heat exchanger to the oil filter.

The oil then continues to the main gallery and from there to the main bearings and the oilways for lubrication of each cylinder head.
The oil is also carried from the main gallery back to the oil pump housing to supply the front main bearing and to regulate the pressure in the relief valve.

Also mounted on the oil pump housing is the oil pressure sensor. When the oil pressure drops too low, the sensor grounds the electrical circuit for the warning lamp in the main instrument display.
The camshaft bearings and tappets are supplied with oil from a horizontally drilled oilway for each camshaft. Each oilway has a purging nozzle to ensure that all air is bled out of the system when starting.


Oil Filter
Since the oil filter has no integral overflow valve, it is not interchangeable with the filter fitted to four-cylinder engines.

The oil filter screws directly onto the cylinder block where it is easily accessible.

The relief valve is mounted in the block below the oil filter. The valve opens when the filter is excessively soiled or clogged and the oil passes through the filter without rupturing it.