Engine Lubrication: Description and Operation

OPERATION
During normal operation oil flows from the adapter inlet through the oil filter. At this point oil flow is controlled by the oil cooler valve. This valve is closed when below its calibrated value and directs the oil filter output to the oil cooler located in the left hand radiator tank. Above the calibrated value the valve unseats and allows some of the oil to bypass the cooler and flow directly to the adapters return passage. Filtered and cooled oil re-enters the crankcase distribution channels and is simultaneously directed to the main bearings. Cross drilled passages in the crankshaft in turn provide oil for the connecting rod bearings and provide splash oiling for the cylinder walls. The lower crankcase distribution channel also connects with passages in the upper crankcase to provide oil to the overhead camshafts and valve lifters. This passage, beside the number one bearing, also provides oil for the three hydraulic chain tensioners as well as lubrication for the cam drive intermediate shaft ultimately lubricating the cam chains via oil splash. Oil for the camshafts and valve mechanisms enters each cylinder head through passages in the upper crankcase below the front camshaft bearing. Oil then enters the camshaft through a drilled passage and travels through the hollow camshafts for delivery to the remainder of the cam bearings. The same cylinder head passage that supplies the camshafts also intersects a longitudinal gallery for each group of valve lifters (intake and exhaust).Oil returns to the sump either through the cam chain area or by way of cast oil drain back passages on the outside walls of the cylinder heads, upper and lower crankcases and oil pan. The lubrication system also includes a baffle, attached by the main bearing bolts, and channels oil thrown from the crankshaft back into the oil sump.