Sunbeam ALPINE I SERIES: APLINE II SERIES, Workshop Manual

Page: 49 / 413

WSM.11.C
Section B (Engine)
-
IGNITION
VERNIER
ADJUSTMENT
Fig. 11.
Distributor
vernier
control
Two adjustments are provided for setting the
ignition tlmlng-
(a) A clamp screw mounted horizontally below
the distributor. This is the main adjustment,
and when It Is slackened, the body of the
distributor can be turned relative to the
mounting plate.
(b) The vernier control shown in Fig. 12. This
provides an easy means of making small ad­
justments to the Ignition timing to give the
best performance from a particular fuel, or to
eliminate pinking when excessive carbon de­
posits have formed in the engine. The knurled
knob should be turned clockwise to retard
and anti-clockwise to advance, one complete
turn of the knob being equivalent to three
crankshaft degrees, and one vernier division,
shown In the inlet of Fig. 12. to four crankshaft
degrees.
.,,,,,,,,,,
..
TO TIME IGNITION
3rd
re-Issue
Page II
Static Ignition settings are given In the Data Section
under "Ignition System".
Before checking the Ignition timing It Is most
Important to see that the contact breaker point gap
is correctly set. This will ensure that the correct
Ignition timing Is obtained each time the contact
breaker points are cleaned and adjusted correctly.
Static ignition settings and contact breaker gap are
given in the Data Section under "Ignition System".
As the contact breaker point gap decreases, through
gradual wear of the moving point heel, the Ignition
timing becomes retarded. ,004• (·10 mm.) Reduc­
tion of contact breaker point gap retards the
Ignition by approximately 2
°
of crankshaft move­
ment. This is equal to half a division on the Vernier
control which Is enough to reduce engine perfor­
mance.