Actron Inductive Timing Light service manual Engine Timing Check, Timing Adjustments

Fig. 1 - Hookup Diagram

RED

BLACK

NOTE

On some engines, the distributor may be mounted very close to the carburetor, or fuel injection throttle body. Since this is an area in which there may be gasoline vapors present, it is adviseable on these engines to remove the number one (1) spark plug wire only at the spark plug end.

Connect the spring adaptor and spark plug lead between the spark plug (or distributor cap) and the removed wire as shown in Figure

1.Route the timing light’s spark plug wire away from the exhaust manifold and surrounding hot areas to prevent damage.

4.Connect the RED clip to the positive (+) battery terminal.

5.Connect the BLACK clip to a secure engine ground such as the alternator bracket or engine block. For safety reasons, do not use the negative (-) battery terminal or fuel system components as a ground connec- tion point.

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ENGINE TIMING CHECK

(Breaker point equipped engines only)

Check and, if necessary adjust dwell to specifi- cation before proceeding with timing check.

1.Prepare the engine for timing as indicated above in ENGINE PREPARATION FOR TIMING.

2.Clean, and chalk if necessary, both the rotating and stationary timing marks on the engine. See Figure 2.

3.Start the engine and allow it to warm to normal operating temperature (upper ra- diator hose is hot).

4.Check, and if necessary, adjust RPM to specified timing speed.

5.When using an advance timing light, make certain that the advance control is set fully counterclockwise at “0”.

6.Aim the timing light at the crankshaft damper (pulley) or transmission bell housing de- pending on the location of the timing marks on the engine under test. See Figures 1 and 2.

7.Pull the trigger switch on the timing light and observe the location of the rotating mark with respect to the stationary mark. If timing is within the tolerance as specified by the manufacturer (typically plus or mi- nus 2 degrees) no adjustment is necessary and the procedure is finished. If it is not within specifications, proceed directly to the INITIAL TIMING ADJUSTMENT section below. If the timing light multiple flashes or flashes erratically on timing lights equipped with an inductive pickup, see NOTE below.

Fig. 2 - Various Timing Light

Configurations

10
	0
DC	3
	10
	6
	A
10	O
	6
	-
	1
	UDC
	16N
TDC	-
	6
	1
	OP

Fig. 3 - Positioning the Inductive Pickup for Reliable Readings

NOTE

A defective ignition system may cause the timing light to multiple flash or flash errati- cally. Low output spark voltage or a defec- tive ignition wire may be responsible. You may be able to steady the flash by sliding the inductive pickup along the plug wire to a new location or reversing the inductive pickup as shown in Figure 3. (This may also help even with polarity sensitive pick- ups). Solid copper ignition wires radiate large amounts of radio frequency noise through the air which may interfere with the proper operation of the timing light and other electronic equipment. Replace solid copper ignition wire with resistance type wire if only for the tests described in this manual. Erratic flashing of the timing light can also be caused by dirt or grease buildup on the mating surfaces of the inductive clamp. To maintain proper operation of the clamp, clean and dry the inside clamp sur- faces with a soft cloth when necessary as shown in Figure 4.

8.Shut off the engine. Disconnect the timing light leads in the reverse order from which they were connected.

9.Re-connect any disconnected hoses or electrical connectors which were part of the engine's preparation for timing. Reset the engine’s idle speed if necessary.

Timing Adjustments

l. Make certain that the engine has been prepared for timing as indicated above in

ENGINE PREPARATION FOR TIMING.

NOTE

The following timing adjustment procedure can be used on the majority of spark ig- nited engines in use today. Both General Motors and Ford Motor Company have introduced and used special versions of their common electronic ignition systems which sense ignition directly from the engine’s crankshaft via a crankshaft sen- sor. These systems were introduced in the late1970’s and were typically used only on a few of the “high line” luxury passenger cars. Timing is still checked with a timing light in the standard manner, however, timing adjustment is made at the crank- shaft sensor, not by turning the distributor as is normally done. See your vehicle serv- ice manual for exact adjustment proce- dures on this type system.

2.With the engine off, loosen the distributor hold down bolt just enough so that the dis- tributor can be turned freely. Do not loosen the bolt beyond this point. See Figure 5.

3.Start the engine and allow it to warm to normal operating temperature (upper ra-

Fig. 4 - Cleaning the Inductive

Pickup

CLEAN AND DRY HERE

Fig. 5 - Loosening the

Hold-Down Clamp

REMOVE	LOOSEN
AND PLUG	HOLD-DOWN
VACUUM	BOLT
HOSE IF
REQUIRED

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