Cadillac 1937 LaSalle VVI Information page 31

Install new plugs if the old plugs are badly
worn. Spark plug manufacturers recommend
new plugs each 10,000 miles. A . C . Spark Plug
Model K - 7 is recommended for LaSalle V-8
cars.
Cleaning the timer contact points in the distributor and
setting to a gap of .012-.018 inch.
Replacement of worn contact points is a
very inexpensive operation that will keep
engine performance lively for a longer period
of time.
Retiming the ignition to the timing marks on the har-
monic balancer at the front of the engine.
The engine is correctly timed when the spark
for the N o . 1 cylinder occurs exactly as the
I G / A (ignition-advance) mark lines up with the
pointer. T o change the timing, loosen the lock
screw on the timing quadrant and move the
distributor housing as required. In this con-
nection, also read the next section.
C a r b o n a n d Detonation—Most automobile owners
have been taught that a detonation or " p i n g " in the engine
is an indication of an over-advanced spark or of carbon i n
the engine, and probably the latter. While this is true, the
following supplementary information must be included when
considering "ping" in any high compression engine.
On cars with high compression engines, slight detonation
occuring on rapid acceleration at low speeds and disappear-
ing at about 15 miles per hour, is normal and indicates that
the engine is performing at top efficiency. Detonation at
higher speeds can be eliminated by checking and correcting
the following:
Grade of gasoline used—The LaSalle V-8 engine is de-
signed for use with 70 octane gasoline (regular). Gasoline
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of a lower rating may be used safely, but in this case the
ignition timing must be retarded to a point where the engine
will not knock.
Over-lean mixture—This may be due to an incorrect
carburetor adjustment or to an obstruction in the fuel feed.
Spark plugs—One or more faulty spark plugs will cause
pre-ignition in their respective cylinders. Replace these
with A . C. model K - 7 spark plugs.
Accumulation of Carbon—Accumulated carbon must be
removed by scraping after taking off the cylinder head.
Removal of carbon by burning is not recommended.
Valve Service—The condition of the valves should a l -
ways be inspected at time of carbon cleaning, and refacing
operations performed i f required. The table below gives the
various limits to be observed in valve reconditioning. Good
workmanship and the use of adequate equipment for this
operation is important.
Valve Service Data:
Inlet Valve Exhaust Valve
Seat Angle 45° 45°
Seat Width _
Seat Eccentricity..- Not over .002' Not over .002'
Stem-guide Clearance 003'—-.006' .003'— .005'
Carburetor—The only adjustment required by the
carburetor is the idling
adjustment.
T h e i d l i n g s p e e d
should be set with the
throttle stop screw to the
equivalent of 6 miles per
hour. The two idle needle
valves should then be ad-
justed until the engine
runs smoothly. These ad-
justments must be made
when the engine is hot.
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