Sunbeam ALPINE I SERIES: APLINE II SERIES, Workshop Manual

Page: 339 / 413

WSM.124
Section N (Elec. Equip.)
Examine the contact breaker. The contacts must
be quite free from grease or oil. If they are burned
or blackened, clean them with very fine carborun­
dum stone or emery cloth, then wipe with a petrol­
moistened cloth. Cleaning is facilitated by
removing the contact breaker lever. To do this
remove the nut, washer, Insulating piece and
connections from the spring anchor post. The
contact breaker lever arm may now be removed
from its pivot. After cleaning, check the contact
breaker setting. Turn the engine by hand until the
contacts show the maximum opening. This should
measure ·015 in. (·38 mm.) If the measurement
is incorrect, keep the engine in the position giving
the maximum opening, slacken the screw securing
the fixed contact plate and adjust its position to give
the required gap (Fig. 19). Tighten the screw. Re­
check the setting for other positions of the engine
giving maximum opening.
SERVICING
Before starting to test, make sure that the battery
is not fully discharged, as this will often produce the
same symptoms as a fault in the ignition circuit.
Testing in position to locate cause of uneven
firing
Run the engine at a fairly fast idling speed.
Short circuit each plug in turn with the blade of
an insulated screwdriver placed across the terminal
to contact the cylinder head.
Short circuiting the defective plug will cause no
noticeable change in the running note. On the
others, however, there will be a pronounced
increase In roughness.
Having thus located the defective cylinder, stop the
engine and remove the cable from the sparking plug
terminal.
Restart the engine and hold the cable end about¼'
(5 mm.) from the cylinder head. If sparking Is
strong and regular, the fault lies with the sparking
plug, and it should be removed, cleaned and
adjusted, or a replacement fitted.
If however, there Is no spark, or only weak Irregular
sparking, examine the cable from the plug to the
OIL CAM
BEARING
,
-
OIL TIMING CONTROL
'4a97
2nd re-issue
Page 21
FIXEO CONTACT SCREW
VERNIER
ADJUSTER
Fig. 19. Distributor maintenance
distributor for deterioration of the insulation,
renewing the cable if the rubber is cracked or
perished.
If the cable is fitted with radio or television sup­
pressor, this should also be checked for damage or
open circuit.
Clean and examine the moulded distributor cap
for free movement of the carbon brush. If tracking
has occurred, Indicated by a thin line, usually
between two or more electrodes, a replacement
distributor cap must be fitted.
Testing in position to locate cause of
ignition failure
Spring back the clips on the distributor head and
remove the moulded cap. Lift off the rotor,
carefully ·levering with a screwdriver If necessary.
Check the contacts for cleanliness and correct gap
setting as described previously.
Connect an ammeter In the low tension wiring,
switch on the Ignition and turn the engine. Observe
the ammeter reading, which should rise with the
closing and fall to zero with opening of the contacts
If the low tension wiring Is In order. When the
reading does not fluctuate, a short circuit, or
contacts remaining closed, Is indicated. No reading