1930 Cadillac Brochure Front Cover - GM Heritage Center

straining. All the oil drained back from the bearings, cylinder walls,
and other parts must pass through this screen before it can reach
the inlet to the pump for a second passage through the system.
As an added protection for the finely machined engine surfaces,
an external oil filter is provided at the right side of the crankcase to
remove all grit and abrasives from the engine oil. Oil passes through
this fil ter under pressure and solid particles are completely removed.
Oil is forced by the pump to a manifold fitting running the entire
length of the crankcase. Leads connect this manifold to the center
and rear main bearings, the rear camshaft bearing, the pressure
gauge, and the oil filter. The crankshaft is provided wil.li oil passages
connecting the journals of the main and the connecting rod
bearings. Oil from the main bearings is delivered to each of the connecting
rod bearings and from there supplied under pressure to the
wrist pins through passages in the connecting rods.
Oil forced from the connecting rod bearings is thrown by centrifugal
force on to the cylinder walls and pistons, lubricating them.
The camshaft receives oil through its rear main bearing, from which
it is led through the hollow shaft and thrown by centrifugal force on
the bearing surfaces of the other three bearings. The pressure
throughout the circulatory system is controlled by a piston valve
pressure regulator mounted on the crankcase in front of the right
cylinder block. Overflow from this valve lubricates the chain and
chain mechanism, and a lead is also provided for pressure lubrication
of the fan bearing.
The valve slems are automatically lubricated through ports in
the cylinder walls which emit a fine mist of oil vapor from the
crankcase ventilating system. This mist provides excellent lubrica-
Airi.s drawn into l.lio crankcase on Uiy the arrows,
building up a pressure within the case, providing an ell'eet.ive crankcase
vcnt.ilal.ion. Vapors are expelled into the pipe at. the left removing all
condensation products.
lion for valve springs, sterns, and guides. Oil level is indicated by a
gauge at the rear of the right cylinder block on top of the crankcase.
This gauge is operated by a float in the oil pan. Oil pressure
in the system is shown on a gaiige mounted on the instrument panel.
CRANKCASE VENTILATION
One of the most significant developments pioneered by Cadillac
is the crankcase ventilating system, which was introduced in 1925
to eliminate the evils brought about through the contamination of
the crankcase oil by water and unburned fuel vapors. Because of this
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