Sealey TL84 - Manual (Page 2)

4. OPERATING PROCEDURES - NORMAL ENGINES
Figure 2
Figure 1
Figure 3
4.1.1 Locate engine timing mark (see figure 1) and use a rag to
clean all grease and dirt from the mark and the pointer. It
may help to use chalk or white paint on the marks to
make them more visible.
4.1.2 Check manufacturer’s specifications for correct timing of
the engine being serviced.
4.1.3 Start and run the engine until normal operating
temperature is reached .
4.1.4 Stop the engine
4.1.5 If specifications require, locate the vacuum line going to
the ignition distributor vacuum advance, disconnect it and
plug the line. A bolt or pencil may be used to seal the line.
4.1.6 Connect the timing light as shown in figure 2.
4.1.7 Start the engine and operate at normal idle speed. Aim
the timing light at the timing mark as shown in figure 3
4.1.8 Trigger the timing light and observe the reading from the
timing mark.
p Caution: Use care when working around a moving
engine. Keep hands, tools and timing light clear of
moving fan, belts or other moving parts.
4.1.9 Compare reading obtained in step 4.1.8 with the
manufacturer’s specifications. If timing is not as
specified, readjust as described below.
4.2 Checking the idle timing (TL85 only)
4.2.1 Set the knob to the ‘0’ position as in figure 4
4.2.2 Follow steps 4.1.1 - 4.1.9
3.1 When To Check Timing
The instant of spark plug firing is determined by the
closing of the distributor ignition breaker points and will
change any time the point gap or dwell angle is changed.
In addition, normal wear on the breaker point rubbing
block will change the dwell and affect the timing. Cars
equipped with the new “breakerless electronic ignition
system” will not normally change timing since there are
no breaker points. For these vehicles, the Timing Light can
still be used to note changes in timing caused by troubles
in the ignition system as well as for resetting timing when
components are changed.
3.2 Timing Specifications
As noted earlier, timing requirements vary from engine to
engine. The engine manufacturer’s specifications should
always be referred to before making any adjustment.
These specifications can be found in the cars owner
manual, on the under bonnet decal required on all cars
manufactured since 1968 and in various automotive
publications.
Figure 4 Figure 5
4.3 Checking the Centrifugal Advance and Vacuum Advance (TL85 only)
4.3.1 Follow steps 4.1.1 - 4.1.7 under ’Operating Procedures’ but increase the
engine speed to 2000 rpm. Trigger the timing light and rotate the knob
clockwise slowly and stop when the timing mark moves to TDC or’0°’.
4.3.2 Observe the reading from the advance scale as shown in
figure 5
4.3.3 Compare the reading with the manufacturer’s specification.
4.4 Adjusting the timing to specifications
4.4.1 Loosen distributor locking bolt located at the base of distributor enough so that
the distributor may be rotated back and forth. Do not over loosen or remove
bolt, but leave it tight enough to prevent distributor turning by itself.
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