Test 10 - Ignition Timing Advance Testing

CENTRIFUGAL TIMING ADVANCE INSPECTION



1. Connect a tachometer and timing light to the engine.
2. START the engine and run at curb idle until the engine has reached normal operating temperature.
3. Disconnect the vacuum hoses from vacuum controller.
4. While slowly raising rpm, check advance, by shining the timing light on the timing mark and watching for mark to move.
5. Check for any of the malfunctions below. If any of these problems are found dismantle and check the distributor and repair or replace damaged components.


SYMPTOM CAUSE


Excessive Advance Weakness of the governor spring
Sudden Advance Broken Spring
Insufficient or Slow Advance Check cam weights for free movement.


6. After checking, let the engine idle and turn the ignition switch to the OFF position.
7. Connect the vacuum hoses to the vacuum controller nipple.
8. Remove tachometer and timing light from the engine.



VACUUM TIMING ADVANCE INSPECTION


1. Connect a timing light to the engine.
2. START the engine run at curb idle until the engine has reached normal operating temperature.

Vacuum Advance Inspection:

3. Disconnect the vacuum hoses from vacuum controller and attach a hand vacuum pump.
4. Check the advance while slowly applying vacuum with the hand pump. The advance should be smooth as more vacuum is applied.
5. Check for any of the malfunctions below. If any of these problems are found dismantle and check the distributor and repair or repace damaged components.

SYMPTOM CAUSE

Excessive Advance Weak vacuum controller spring
Sudden Advance Broken spring
Insufficient or Slow Advance Impaired base plate movement.
No Advance Broken Diaphragm


6. After checking advance, let engine idle and turn the ignition switch to the OFF position.
7. Remove vacuum pump and connect the vacuum hoses to the vacuum controller.
8. Remove the timing light from the engine.