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3-6
SERVICE RECOMMENDATIONS
ENGINE FUEL AND EXHAUST SYSTEMS
(80)
resonance chambers which absorb and dampen
out the exhaust sound waves. A slip joint at
one end allows for expansion and contraction
due to temperature changes. See figure 3-8.
[
SLIP
JOINT
Figure 3-8-MufRer-Sectionol View
The word "Front" is stamped on one end of
the outer shell of muffler to indicate the end to
place toward front of car during installation.
The drain hole in outer shell should always be
located at the bottom.
There should be a minimum clearance of 1"
between the tail pipe and the rear seat pan at
the closest point.
3-4 SERVICE RECOMMENDATIONS
a. Use of Accelerator Pedal for Starting
Engine
To avoid complaints of hard starting, owners
should be advised on the proper use of the
accelerator pedal for starting the engine.
When the engine is cold, depress the accelera-
tor pedal just far enough to cause cranking
motor to engage and crank the engine. Do not
pump the pedal as this will cause the accelerat-
ing pump to flood the manifold.
When the engine is partially warm, hot, or
flooded, depress accelerator pedal to the floor
and hold it until engine fires regularly. This
procedure actuates the choke unloader on the
carburetor to prevent or to clear up a flooded
condition.
b. Fuel Selection
The compression ratio of the Series 40 engine
is such that a grade of fuel having an octane
rating of 72 to 74 can be used satisfactorily.
Under certain conditions such as high tempera-
ture and carbon accumulations, higher octane
number fuel will result in less detonation or
spark rap. Fuel having an octane rating of 78
to 80 is required in Series 50-70 engines be-
cause of higher compression ratios.
c. Fuel Additives
Gasoline extenders, carbon removers, valve
and ring freeing additives to the fuel may
seriously affect lubrication or may cause corro-
sion of the engine parts and generally do more
harm than good. The addition of any compound
to the fuel for break-in or otherwise is unneces-
sary and should not be used unless the supplier
can furnish satisfactory proof that the com-
pound does not contain harmful ingredients.
d. Cars in Storage
When car is stored for any length of time,
fuel should be drained from the tank, feed
pipes, fuel pump, and carburetor in order to
avoid gum formation.
e. Changing Carburetor Calibrations
Under no circumstances should the jet sizes,
metering rods and other calibrations of a car-
buretor be changed from factory specifications.
The calibrations given in paragraph 3-1 must
be adhered to unless these are later changed by
a bulletin issued from the Buick Factory Serv-
ice Department.
Carburetor calibrations have been determined
after exhaustive tests with laboratory equip-
ment and instruments which accurately meas-
ure overall performance and economy. Since
equipment and instruments of identical accuracy
are not available for field use, it is not possible
to properly measure the effect of a change in
calibrations by any means available in service
stations.
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