Morning David (and all),
Results of yesterdays tests with a vacuum gauge are attached. The chart details the exact sequence of checks accomplished and their effects on the engine.

To clarify a few questions that may arise:
1) The distributor is not moving around on its clamp.
2) The damper is not separated and slipping.

My conclusion is that something is sticking within the distributor. Either the mechanical or Vacuum advance. I will be contacting Summit as they supplied it. In the interim, I will reinstall the original unit and coil.

 

Ian
Quite a journey... persistence and good documentation...process of elimination...satisfaction with a clear result... still frustrating to have a new-out-of-the-box failure.
Best wishes with quick response from Summit and Pertronix
Rgds
David

 

Not too hard to check out the Pertronix or any other distributor wit mechanical and vacuum advance.

1. Mechanical aka centrifugal. With unit in the car, twist the rotor back and forth It should move freely.

2. Use a vacuum source. Mitty VAC or similar. or another car!! Attach tot the can Apply vacumn. The plate securing the Pertronix box or the points should respond, freely...

Way out there. Worn teeth on the jack shaft in the engine.. Slight tolerance between original and the Pretronix allows an OK mesh with the Original, but not quite with the Pertronix.

Try the rotor twist, again, Not sure if that would detect a mismatch..

A strobe would be best....
Carl

 

So until I hear back from Pertronix, I have reinstalled the original distributor and coil, and set the timing as per the original maintenance handbook. 17 deg. BTDC with Vac capped, at 800 rpm. Timing does not change when the vac. is reapplied.

The engine is now smooth as silk with a very stable idle. When the AC is switched on, rpm drops to about 650, but remains stable. Not like before when the engine would stumble and die. Also, on the road it seems to be somewhat down on power, so I will try timing it in 2 deg. BTDC increments until I get a ping or unstable idle then back it off slightly.

Until this whole exercise, I had never actually checked the timing, but it always had a rough idle. Not anymore.

If this really turns out to be a defective Pertronix unit, I would still like to see what difference if any a functioning unit could make.
Ian