1999 Volvo Penta "WT" Models Workshop Manual, Page 225Get this manual
Pistons and Connecting Rods The pistons are cast aluminum that use two compression rings and one oil control ring assemblyThe piston pins are floating fit in the pistons and are retained by press fit in the connecting rod assemblyConnecting rods are forged steel, with precision type insert crankpin bearings
Lubrication
The gear-type oil pump is driven through an extension driveshaftThe extension driveshaft is driven by the distributor which is gear driven by the camshaftThe oil is drawn from the oil pan through pickup screen and tubePressurized oil is delivered through internal passages to lubricate camshaft and crankshaft bearings and to provide valve lash control in the hydraulic valve liftersOil is metered from the valve lifters through the valve push rods to lubricate the valve rocker arms and ball pivotsOil returning to the oil pan from the cylinder heads and the front camshaft bearing, lubricates the camshaft timing chain and crankshaft and camshaft sprockets