1930 Cadillac Brochure Front Cover - GM Heritage Center

£2&ai
from a high quality steel; inlet valves being of tungsten steel and
exhaust valves of silico-chrome. The clear diameter of the intake
valve is 1¾ inches, while that of the exhaust is 1^ inches. The
valve stems have their bearings in guides pressed into the cylinder
blocks. The valve lift is || inch. Intake valve seat3 are at an angle
of 30 degrees, in order to give freer passage to the gases when the
valves are opened. The exhaust valves are at an angle of 45 degrees,
in order to compensate for the difference in expansion between the
cylinder blocks and valve stem. The combustion chamber is designed
so as to eliminate all masking of the valves, greatly improving
volumetric efficiency.
Cadillac valves are operated through cam slides placed in groups of fours.
Adjustment when required is easily effected with only a screw driver and
a single wrench. This cam slide construction eliminates the necessity of
holding the tappet in position while the adjustment is being made.
excess weight and to provide a passage for oil which is supplied to
each of the bearings under pressure. Each valve is actuated by a
cam slide carrying a hardened steel roller which rides upon the cam.
The cam slides operate in bushings assembled to the crankcase in
groups of four. These bushings are very accurately machined and
aligned, with dimensions whose limits vary no more than .0005 of an
inch. The cam slides are maintained in a fixed position which
simplifies adjustment since only a screw driver and a single wrench
are necessary for this operation. The Cadillac valves are forged
CHAIN MECHANISM
The camshaft is driven from the crankshaft by a silent chain.
A chain drive lias several advantages over gears in that it provides
a flexible connection between
these two shafts,
giving opportunity to
absorb minor vibrations
caused by the valve
springs. A chain is also
quieter than a gear and,
when properly lubricated,
will retain its quietness
throughout its life. A
second silent chain is used
to drive the water pump
and generator.
Aluminum for crankcases, carburetors, and
other parts is melted in these oil-fired furnaces
trhich are maintained at the proper •
temperature
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