Sunbeam ALPINE I SERIES: APLINE II SERIES, Workshop Manual, Page: 52 / 413

I
st re-issue
Page 14
This is 16 ° crankshaft centrifugal advance plus 8
°
static advance timing.
The 16
°
BTDC crankshaft centrifugal advance angle
is twice the distributor centrifugal advance angle.
This angle has been obtained by plotting the
centrifugal advance figures given under " Ignition "
in the Data section.
Mark
24 °
BTDC on the pulley rim. If the pulley
has only a TDC mark this is 30·5 mm. BTDC when
marked from TDC with dividers.
Start the engine and increase the speed from idling
to 3,000 r.p.m. and then reduce to 2,500 r.p.m.
The white line en the pulley rim should approach
the fixed pointer on the timing case with increase
of engine speed and appear adjacent to the fixed
TDC pointer at 2,500 r.p.m., when observed
by the stroboscopic timing light.
Jerky movements of the white line, marked on the
pulley rim, while increasing or decreasing engine
speeds, indicates that the centrifugal advance
mechanism is sticking.
The distributor advance tolerance is± 2 crankshaft
degrees.
5.
Checking the vacuum advance action
The throttle should be opened to give an engine
speed of 1,200 to 1,500 r.p.m.
With the engine
running under these conditions, the vacuum con­
nection on the distributor diaphragm should be
alternately disconnected and reconnected whilst
observing the line on the crankshaft damper rim,
This should retard and advance as the end of the
vacuum pipe Is removed and refitted. Blockage of
the vacuum feed pipe, vacuum feed hole, or jamming
of the contact breaker point mounting plate, will
prevent correct vacuum advance action.
Ignition timing-Road performance test
After setting the static ignition timing and check­
ing centrifugal and vacuum advance action as pre­
viously described, a road performance test can be
made by taking stop watch readings of the time
taken to accelerate in top gear from 20 to 50 m.p.h.
(32 to 80 k.p.h.) under full throttle conditions on
a straight level road· Small adjustments are then
WSM.124
Section B (Engine)
made with the vernier control on the distributor
until the lowest stop watch reading is obtained.
Several test runs have to be made ON THE
SAME ROAD.
This test requires considerable skill and should only
be undertaken by those who have the necessary
road testing experience.
It is emphasized that the distributor centrifugal and
vacuum advance mechanism must be working
correctly and if these are In any way suspect, after
checking unit the distributor in position, the
distributor should be removed and checked on a
. reliable test rig or distributor analyser. The use of
a Crypton test equipment that allows the Ignition
advance angle to be read off against engine speeds
with the distributor removed is recommended.
Distributor centrifugal and vacuum advance figures
are given in the Data Section under ,;Ignition".
DISTRIBUTOR
To remove and refit
Remove high tension leads from plug terminals,
noting their positions. Disconnect high tension
lead at coil. Disconnect low tension lead at distri­
butor body. Disconnect vacuum pipe. Remove two
setbolts securing aluminium distributor housing to
crankcase and withdraw distributor and housing
together.
Refitting is a reversal of the above.
A special cranked ring spanner (VLC tool) 1· A/F
hexagon is most suitable for removal of the bolts.
To fit replacement Distributor
Before fitting a replacement distributor turn the
engine so that the timing mark on the crankshaft
pulley (or damper) comes opposite to the pointer
on the timing case when the distributor driving
slots In oil pump gear are in the position illustrated
in Fig. 36.
Install replacement distributor.
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