Section VII. ENGINE LUBRICATION SYSTEM
195. Operational Description
The lubrication system of the engine is of a pressure and splash type. An internally mounted oil pump is driven by
the camshaft and delivers the oil under pressure to the main bearings, connecting rod bearings, camshaft bearings, and
timing gears. The pistons, cylinder walls, piston rings, valve tappets, and valve stems are lubricated by oil splash from the
connecting rod bearings and crankshaft. The oil pump forces the oil through a bypass-type oil filter which traps sediment
and dirt. The oil pressure is controlled by an externally mounted oil pressure relief valve. The normal oil pressure is from
10 to 15 psi at idling speeds and from 30 to 50 psi at sustained governed speeds.
196.
Oil Pump
a General. The internally mounted oil pump is a helical-gear type and is driven by the spiral gear on the camshaft.
The oil pump supplies direct oil pressure to the main bearings, connecting rod bearings, camshaft bearings, and timing
gears. With the engine hot, the oil pump delivers from 10to 15-psi pressure at idling speeds and from 30to 50-psi
pressure at sustained governed speeds.
b Removal.
(1)
Run the engine until it reaches normal operating temperature. Drain the oil.
(2)
Remove the oil pan (par. 126a).
(3)
Remove the mounting nut (7) and lockwasher (6) attaching the oil pump to the mounting stud (5).
(4)
Turn the pump counterclockwise slightly to disengage it from the camshaft gear. Pull out the pump from the
cylinder block.
c Disassembly.
(1)
Use a small drift to drive out the drive gear pin (24).
(2)
Remove the drive gear (2) from the drive shaft (8).
(3)
Use a blunt screwdriver to spread the lock wire (21) until it snaps off the outer edge of the screen (20).
(4)
Remove the screws (16) and lockwashers (15) attaching the spacer (19), strainer frame (18), and gasket
(17) to the oil pump body (4).
(5) Remove the spacer (19), strainer frame (18), and strainer frame gasket (17).
(6) Remove the screws (16) and lockwashers (15) attaching the cover (14) to the pump body (4).
(7) Remove the cover (14) and cover gasket (13).
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