1928 Cadillac - GM Heritage Center

90 CADILLAC OPERATOR'S MANUAL
the cam either with a wrench or with the rotor (Fig. 43). Turn the cam
clockwise to advance the ignition, or counter-clockwise to retard it. After
moving the cam, tighten the screw and
check by again cranking the engine and
noting the position of the flywheel
when the spark occurs.
(TURN CAM VERY LITTLE
[ATA TIME
Figure 4}. The ignition is timed by
adjusting the cam on the tinier shaft.
To check the timing for the evennumbered
cylinders, disconnect the wire
from the No. 2 spark plug. Then crank
the engine by hand, the same as before,
stopping the instant the spark takes
place. The mark 'f | £ on the flywheel
should then be opposite the pointer.
If the ignition for the odd-numbered
cylinders has been carefully timed, the
ignition for the even-numbered cylinders
will ordinarily be correct. If it is
not, it is best to have the distributor
serviced at a Cadillac service station,
where a gauge is available for setting
In an emergency, however, the
the plate which carries the adjustable arm.
timing of the even-numbered cylinders can be corrected as follows:
^Loosen the two screws shown in Fig.
44. Then carefully turn the eccentric
adjusting collar with a screw-driver,
turning the collar clockwise to retard
the ignition and counter-clockwise to
advance it. Be sure to tighten the screws
after the correct adjustment has been
secured.
Spark Plugs
For best results, the electrodes of the
"•-?
spark plugs should be .025 to .028 inch TURN COLLAR TO ADVANCE
OR RETARD SPARK
apart. If the spark plugs should be
removed, it is recommended that the Fi gun 44. The contact arm for the evenelectrodes
be inspected and adjusted to numbered cylinders must be synchronized
r
with relation to the contact arm for the
this clearance.
odd-numbered cylinders.
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Lamp Bulbs
GENERAL INFORMATION 91
Lighting System
It is recommended that bulbs for the lamps, particularly the two-filament
bulbs for the headlamps, be purchased from a Cadillac distributor or dealer.
In any event, bulbs should have the correct voltage and candle-power ratings.
The bulbs and the lamps in which they are used are as follow:
LAMP
VOLTAGE
Headlamps 6-8
Inspection Lamp 6-8
Stop Light 6-8
Side Lamps 6-8 \
* Instrument Lamps (2) 6-8 I
* Rear Lamp 6-8 3
Closed Car Dome Lamps 6-8 I
Running Board Step Light 6-8 / '
Cleaning Headlamp Reflectors
CANDLE-POWER
21 (Two-Filament)
Mazda No. 1110
21
15
The headlamp reflectors are plated with pure silver. Although the
reflectors ordinarily require no attention, if they should require polishing,
extreme care must be exercised to select materials that
will not scratch the silver. In polishing reflectors, always
rub from the bulb outward, do not rub in circles.
Powdered dry rouge and a chamois skin are recommended.
If the reflectors are tarnished, the rouge may
be moistened with alcohol. Afterwards, polish with a
dry chamois and rouge.
The chamois used for the headlamp reflectors must
not be used for any other purpose. It must be soft and
free from dust.
Do not touch tin reflectors uith the bare hands.
Figure 45. Do;:blefilament
headlamp
Adjustment of Headlamps
bulb.
Approval of the headlamps by the state authorities is
conditional upon the headlamps being adjusted to a
definite standard. The directions which follow are for this standard adjust
ment.
*Bulbs rated at 3-4 volts, such as arc used in the rear lamps of some cars, must not be used in
these lamps. If installed, they will burn out almost immediately.