1917 Cadillac - GM Heritage Center

66 ADJUSTMENTS
ADJUSTMENTS
67
DISTRIBUTOR AND TIMER
The distributor and tinier (Fig. 33) are carried on the fan shaft housing,
and are driven through a set of spiral gears attached to the fan shaft. The
distributor consists of a cap or head of insulating material, carrying one
contact in the center with eight additional contacts placed at equal distances
about the center and a rotor which maintains constant communication with
the center contact..
The rotor carries a contact button which serves to close the secondary
circuit to the spark plug in the proper cylinder.
TIMER CONTACT POINTS
The distributor head is protected by an aluminum cap, to which are
attached the conduits which carry the high tension wires to the spark plugs.
The timer contact points are accessible after removing the aluminum cap, the
distributor head and the rotor. To do this proceed as follows:
Remove the screws holding the high tension conduit brackets to the
aluminum cap. Slip the bail on the cap to one side and remove the cap.
Press back the finger of the clip on the left side of the distributor head and
rotate the head until both clips are opposite the flat places on the head.
Then lift the head straight up. Remove the rotor by carefully lifting it
straight up. The contact points are then accessible, appearing as shown in
Fig. 34.
Two sets of timer contact points are provided. The object is to distribute
over two sets of points the current which would otherwise pass through
one. This greatly lessens wear and burning of the points.
TO SET CONTACT POINTS
To set contact points
proceed as follows:
Turn the engine over
until the contact arms "D"
and "C" are directly on
top of lobes of the cam
"B." Then adjust the
contact points at "E" and
"F" so. that they stand
twenty thousandths of an
inch apart.
Both sets of contact
points should be adjusted
exactly alike.
Do not file or grind
the contact points. To
clean the points remove
them and simply rub them
over an oil stone two or
three times. Then replace
and adjust, following instructions
given.
It is a good plan after
adjusting the timer contact
points to check the
ignition timing. See below
under "To Time Ignition."
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Fig. 34. Timer Contacts, Distributor Cap
and Rotor Removed.
Fig. 33. Distributor and Timer, Sectional View.
Beneath the distributor head and rotor is the timer. The timer cam is
provided with a lock screw in the center of the shaft. (See Fig. 34.)
An automatic control takes care of the spark position for all ordinary
driving. A spark lever is provided, however, by which the ignition timing
inay be still further advanced or retarded. (See under "Manual Spark Control,"
page 22.)
TO TIME IGNITION
Unless the timer contact points are in proper adjustment they should be
re-adjusted before proceeding to time the ignition.
To time the ignition proceed as follows:
Move the spark lever to the extreme left on the sector; open the compression
relief cocks on the cylinder blocks, and crank the engine by hand
until the piston in No. 1 cylinder is on firing center. (No. 1 cylinder is the
one nearest the radiator in the left hand block of cylinders.)