LUBRICATION SYSTEM - Continued
The oil pump is placed in the crankshaft front cover and consists of a pair of spur gears, one large and one small,
which mesh together and ride in a cavity inside the crankshaft cover. The large gear is concentric with and splined
to a pump drive hub on the front end of the crankshaft. The pump idler gear is much smaller and runs on a
bushing and hardened steel shaft pressed into the crankshaft cover. The oil is drawn by suction from the oil pan
through the intake screen and piped to the oil pump where it is pressurized. The oil then passes from the pump
into a short gallery in the cylinder block to the oil cooler adapter plate. At the same time, oil from the pump is
directed to a spring-loaded pressure relief valve mounted on the cylinder block. This valve discharges excess oil
directly to the oil sump when the pump pressure exceeds 105 PSI (724 kPa). From the oil cooler adapter plate,
the oil passes into the full-flow filter, through the oil cooler and then back into the cylinder block where a short
vertical oil gallery and a short diagonal oil gallery carry the oil to the main longitudinal oil gallery through the
middle of the block. Valves are also provided to bypass the oil filter and oil cooler should either one become
plugged. Stabilized lubricating oil pressure is maintained within the engine at all speeds, regardless of the oil
temperature, by means of a pressure regulator valve located at the end of a vertical oil gallery connected to the
main oil gallery. This vertical gallery is located at the front of the cylinder block on the side opposite the cooler.
When the oil pressure at the valve exceeds 50 PSI (345 kPa) the regulator valve opens, discharging oil back into
From the main oil gallery, the pressurized oil flows through drilled passages to each main bearing then passes to
an adjacent pair of connecting rods by means of grooves in the unloaded halves of the main and connecting rod
bearings and drilled passages in the crankshaft. The rifle drilled connecting rods carry oil from the rod bearings to
the piston pin bushing. At the rear of the block, two diagonally drilled oil passages, which intersect the main oil
gallery, carry oil to the two rear camshaft end bearings. Oil is then conducted through the rifle drilled camshaft to
the intermediate and front end bearings. Oil from the camshaft intermediate bearings is directed against the
camshaft lobes and cam rollers which run in an oil bath. This oil from the intermediate bearings provides
lubrication of the cam lobes immediately after starting the engine when the oil is cold and before camshaft bearing
oil flow and oil drainage from the cylinder head have had time to build up. The diagonally drilled oil passage on
the right side at the rear of the block intersects with a vertical passage to carry oil to the right bank cylinder head.
A short gallery also intersects with this diagonal passage to lubricate the idler gear bearing. Another gallery
intersecting the diagonal passage from the camshaft at the front of the block supplies oil to the left bank cylinder
head. Drilled passages, intersecting longitudinal galleries which parallel the camshafts, lead to the blower and
supply oil for the blower drive gears and bearings.
Oil from the right-bank camshaft front end bearing lubricates the water pump drive gear and bearings and the
front camshaft gear. The gear train is lubricated by the overflow of oil from the camshaft pocket spilling into the
gear train compartment and by splash from the oil pan. A certain amount of oil also spills into the gear train
compartment from both camshaft rear end bearings, the blower drive gear bearing, and the idler gear bearing.
The blower drive gear bearing is lubricated through an external pipe from the blower rear end plate to the blower
drive support. The valve and injector operating mechanism is lubricated from a longitudinal oil passage, on the
camshaft side of each cylinder head, which connects to the main oil gallery in the cylinder block. Oil from this
passage enters the drilled rocker arm shafts through the lower end of the rocker shaft bolts and rocker shaft
brackets. Excess oil from the rocker arms lubricates the exhaust valves and cam followers.
The gear-type lubricating oil pump is mounted in the crankshaft front cover, which also functions as the oil pump
body. The pump consists of two spur gears which mesh and rotate in a cavity inside the crankshaft cover. The
pump drive gear is concentric with and splined to a pump drive hub on the front end of the crankshaft. The pump
driven gear and bushing assembly rotates on a hardened steel shaft. One end of the driven gear shaft is pressed
into the crankshaft front cover and the other end is supported in the oil pump gear retaining plate.