Initial Timing Check; Initial Ignition Timing Adjustments - Ford VSG-411 Service Manual

Ignition System
INITIAL TIMING CHECK
Manually turn engine to locate timing notch on crankshaft
pulley and, using a piece of chalk, highlight notch (Figure 5).
Connect timing light to engine as per manufacturer' s instructions,
start engine and allow to idle at specified idle speed. Disconnect
and plug vacuum hose and check ignition timing. Refer to specifi-
cations. Adjust as required.
Do not disconnect timing light or reconnect vacuum hose at this
stage.
FIG. 5 Timing Marks
A - T.D.C. Notch on Crankshaft Pulley
6 - Timing Marks on Front Cover
DISTRIBUTOR SPARK ADVANCE TEST
To carry out ignition advance checks, the timing light must be
of the type that includes an advance meter.
With timing light still connected, restart engine and hold at
2000 rpm. Adjust timing light to bring crankshaft notch back to
initial timing mark and note mechanical advance on timing light
meter. Reconnect vacuum advance hose and adjust timing light to
bring crankshaft notch back to initial timing mark. The meter will
measure totai advance. To obtain a vacuum advance figure, sub-
tract mechanical advance figure from total.
When investigating ignition problems a more detailed check of
the advance characteristic may be required at varying engine rpm
and vacuums. This can be done with a tachometer and vacuum
Pump-
1. Connect pump directly to distributor (Figure 6).
2. Start engine and adjust idle to 1000 rpm.
3. Adjust timing light to bring crankshaft notch back to TDC and
note mechanical advance.
4. Pump vacuum to required figure (refer to specifications),
readjust timing light and note advance.
To calculate vacuum advance, subtract mechanical advance
obtained in step 3 from total advance obtained in step 4.
5. Repeat step 4 at varying vacuum figures.
6. Remove vacuum pump and check mechanical advance at
varying engine r-pm.
Figures quoted in the Specification Section do not include the
initial static advance.
7. Reconnect vacuum advance hose.
FIG. 6 Vacuum Pump Connected to Distributor
ADJUSTMENTS
INITIAL IGNITION TIMING
The timing marks and their locations are illustrated in Figure 7.
For checking and adjusting the ignition timing with a scope
refer to the scope manufacturer' s instructions. To check and adjust
the timing with a timing light, proceed as follows:
1. Clean and mark the specified timing mark with chalk or white
paint.
2. Disconnect the vacuum line and plug the disconnected vac-
uum line.
3. Connect a timing light to the No. 1 cylinder spark plug wire.
Connect a tachometer to the engine.
4. Start the engine and reduce the idle speed to 600 rpm to be sure
that the centrifugal advance is not operating.
5. Direct the timing on the timing marks. The light should flash
just as the notch on the pulley lines up between the 4 and 8.
Check specifications for correct initial ignition timing.
6. If the timing is not to specification, loosen the distributor
retaining bolt and rotate the distributor body until the marks
are in line.
Ignition timing is advanced by clockwise rotation of the
distributor body, while counterclockwise rotation retards
timing.
7. Tighten distributor retaining bolt and connect vacuum hose.