ENGINE LUBRICATION SYSTEM
This is by dry sump system. OH feeds, by gravity, from the oil tank to the pump In the
crankcase. The pump forces oil to various parts, which then drains to the bottom of
crankcase sump. The pump then returns oil to the tank. This process is continuous
while the engine Is revolving. The pump Is so designed that it has a greater capacity
on the return side to that on the delivery side to ensure that all oil is extracted from
the crankcase. A felt cartridge filter, In the oil tank, removes foreign matter collected
by the oil In Its passage through the engine. A metal gauze strainer Is fitted to the oil
feed pipe in the oil tank to prevent pieces of fluff, etc., which may find their way into
the tank when replenishing, from entering the oil pump. (See Illustration 3.)
Felt filter and metal strainer should be cleaned in petrol each time the oil tank is drained.
ENGINE OIL PUMP
The pump has only one moving part. This Is the plunger which revolves and reciprocates.
Rotation is caused by the worm gear on the timing side flywheel axle. Reciprocation
is caused by the guide pin which engages in the profiled groove cut on the plunger.
Oil is fed to the pump through the lower of the two oil pipes between tank and crank-
case and is returned through the upper pipe.
If, for any reason, the crankcase is dismantled the oil pump plunger must be removed
from its housing before attempting to separate the crankcase halves. It is
not necessary to remove the small timing pinion which will pass through in situ.
IMPORTANT
Under no circumstances should either the pump plunger or guide screw be disturbed
in ordinary routine Maintenance.
ENGINE OIL CIRCULATION
The oil pump forces oil through :—
(a) Passages drilled through the timing side flywheel axle, timing side flywheel and crank
pin to lubricate the timing side bearing and the big-end bearing. The splash passes
to interior of cylinder, to lubricate the cylinder and piston, and then falls into the
crankcase sump.
(b) A passage In crankcase, controlled by ball valve, direct to the cylinder, to assist in
cylinder and piston lubrication and then falls Into the crankcase sump.
(c) A passage in timing gear case where it " builds up " to a predetermined level to
lubricate the timing gears and then overflows into the crankcase sump.
(d) Through a pipe from the front of oil pump housing to the rocker box by which
all rocker gear and valve stems are lubricated and then falls through the push rod
cover tubes and tappet guides to the timing gear case and. from there, drains into
the crankcase sump, as detailed in Para. (c).
The oil pump extracts oil in the crankcase sump and returns it to oil tank. On its way
it passes through the felt cartridge filter located in the oil tank.
D—S.
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