1928 Cadillac - GM Heritage Center

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itire length. Each valve is actuated by a cam slide carrying a hardened
roller, which rides upon the cam.
'he cam slides operate in bushings assembled to the crankcase in groups
til-. These bushings arc very accurately machined and aligned, and have
nsions whose limits vary by no more than .0()().5 of an inch. The cam
s, which operate the valves, have easily manipulated adjustment screws,
'lie Cadillac poppet valves are forged from high quality special steel.
valves are tungsten steel and exhaust valves are silico-chroine steel,
'he clear diameter of the valve is approximately 1 1 ) inch. The valve
s have their bearings in guides :!,'„- inches long pressed into the cylinder
;s. This length prohibits the possibility of wear. The valve lift is | J inch,
'he exhaust valve seats arc at an angle of 45 degrees. The inlet valve
arc at an angle of :5() degrees in order to give freer passage to the
; when the valves are opened.
CHAIN" MECHANISM
ilent timing chains are used. They have the advantage of being quieter
gears, and of retaining this quietness throughout their life.
A large sprocket is keyed directly
to the camshaft and is driven from the
crankshaft sprocket by a silent chain,
while anot her silent chain, from a second
crankshaft sprocket, drives the water
pump and generator.
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EXHAUST
MANIFOLDS
The two cylinder blocks have separate
exhaust manifolds, the front ends
of which join a common manifold connected
to a pipe passing down between
the engine and the frame. The exhaust
pipe is thus kept as far as possible from
the floor boards, to insure a cool driving
compartment in summer. A tail
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pipe from the muffler carries the exhaust gases to the extreme rear of the
chassis, making for unusually quiet operation.
SUSPENSION
Cadillac employs three-point engine suspension. Rubber lined mountings
are used to support the engine at the two points at the rear of crankcase and
a ball-and-socket joint at the front cover plate.
These rubber mountings act as a complete insulation of engine from frame
and any engine noises that might possibly develop cannot be transmitted to
the interior of the car, thus preventing body rumbles.
The rubber is of great durability and holds the power plant rigidly. By
this development the engine is relieved of acting as a cross member for the
frame, a special strong steel tubular cross member being incorporated in the
frame at this point.
FUEL SYSTEM
A 20-gallon tank at the rear of the frame is provided. Feed is by vacuum
to a smaller tank on the dash. A large sized tank filler projects outside the
frame member giving great accessibility, a vent pipe incorporated in the filler
permitting the escape of air and thus preventing splashing when the tank
is filled.
VACUUM I-UMF
Vnlike most vacuum systems, which depend solely upon the intake manifold
vacuum, the flow of fuel to the carburetor is positive under all conditions
and even when climbing the longest hills, and running at top speed for
long distances. This is assured by a special vacuum pump, placed at the rear
of the crankcase and driven by an eccentric on the camshaft. The pump, together
with the intake manifold vacuuin, provides the vacuuin necessary to
lift the gasoline to the vacuuin tank, under all conditions, from which it
flows to the carburetor. This arrangement is entirely unique anil is protected
by Cadillac patents.
FUEL STUAIXEll
The engine fuel is cleaned of dirt and water twice between the gasoline
tank and the carburetor by two straining devices; once before reaching the
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