1938 Cadillac V16 - GM Heritage Center

Cadillac-LaSalle Preliminary Service Information 15
C
Carburetion and Manifolding.—Gasoline
is drawn forward from the 26 gallon tank through
a single pipe placed in a cool position outside of
the right hand frame sidebar. This pipe branches
near the front of the engine, with one lead passing
directly to the right hand fuel pump and the other
one crossing in front of the frame front crossmember
and then back to the left hand fuel pump.
Heater for
Automatic
Choke
Automatic Choke
Thermostat —
C
The two fuel pumps are of the familiar linkdriven
flexible diaphragm type. The link drives
project inward and engage push rods operated by
eccentrics on the distributor drive shafts, as shown
in Fig. 13. Gasoline filters are an integral part of
the pumps.
A pipe leads from the right hand fuel pump to
the right hand carburetor, and from the left hand
pump to the left hand carburetor, but these lines
are interconnected so that either pump may supply
both carburetors.
Two heavy duty oil bath "air cleaners of cylindrical
design are each mounted directly above the
corresponding carburetor. Two \Y£ Carter carburetors
are employed. The carburetors are of
dual downdraft design, with one carburetor barrel
serving the four inside cylinders, while the other
serves the four end cylinders. (See Fig. 14.)
These carburetors are of the same design and
construction as the Carter carburetors used on the
V-8 engines and are adjusted and serviced in
exactly the same fashion. Synchronizing the
action of the two carburetors can be accomplished
in the same manner as for 37-90 carburetors, either
Intake Manifold
for inner four
cylinders
» Intake
»" * Manifold
for outer '
four cylinder-,
Fig. 14. Carburetors and manifolds used on the 38-90
engine
by the use of the mercury column gauge or by
running each bank of cylinders separately. A
trunnion with closely threaded adjusting nuts is
incorporated in each throttle rod near the carburetor
to permit accurate synchronization.
The fuel mixture passes down from each carburetor
to an exhaust heated chamber, and then to
the four passages of the dual intake manifolds,
which are so arranged that no two successively
firing cylinders draw from the same manifold passage.
All exhaust ports are single. The two center
Eorts of each cylinder bank are connected to the
eating passages for the intake manifolds. The
two exhaust pipes discharge into a cross pipe just
behind the carburetors and this pipe conducts the
exhaust gases to the left side of the engine and
downward to the rear.
Eccentrics
\ /
Gear on
Camshaft-
^51
A vacuum pump to insure effective windshield
wiper operation at all speeds and throttle openings
is mounted above the valve chamber cover at the
rear of the engine. It is similar to the pump used
on 37-90.
Engine Supports.—The 38-90 V-16 engine is
supported at five points by the same type of rubber
mountings as are used for the V-8 engines. There
are two supports at the front corners, two intermediate
supports, and a rear support at the transmission
extension. The rear support has rV"i 0cn
steel shims between the top plate and the transmission
extension, in place of the )^-inch steel
washer used on V-8 engines.
Fie 13
Phantom view of distributor and fuel pump drive
mechanism on 38-90 engine
Adjustment of the engine supports consists
merely of tightening all bolts to a snug fit, except
at the rear support where adjustment is made by
varying the number of shims.