Over the weekend, I started my newly rebuilt engine for the first time. I couldn't get it to fire with the Pertronix and reverted back to the points before I screwed up my cam. After getting the car running, I put the Pertronix back in, but still no dice.
I posted a plea for help that Midlife responded to. I tried his suggestions, but still couldn't get it to work.
I spoke with the a Tech at Pertronix Monday and yesterday I tried what he suggested. It worked and I just wanted to put this out there since I've never read this dicussed before.
The magnetic exciter ring was sitting too low on the distributor shaft relative to the heigth of the ignitor module. I used a rubber garden hose washer to raise the magnet ring up about 0.125" and now it sits flush with the top of the ignitor. The rotor still bottoms out without contacting the magnetic ring.
I put it all back together and tested it. I HAVE MAJOR BLUE LIGHTNING SHOOTING OUT OF THE COIL!!!
The engine now fires right up with almost no cranking.
Hmmmm, well whatever works in a pinch is what works. I'd be a little concerned that you might not get the reliability that you want out of a rubber garden hose washer.
You might take a look at the end play on the distributor shaft to find out if your bearings are worn out and the thrust is out of spec.. You can set this end play when rebuilding a distributor by playing with the spacer between the cam gear and distributor body, and shimming the top thrust bearing. Also you might want to take a look at your cam gear and the way the thrust surface is on that.
Actaully, the distributor is a new (rebuilt) unit. It hardly has any end play. What you stated was something the Pertronix Tech said to look for as well, but I don't have that issue.
I used the hose washer because it was the thickness and diameter I needed and is non-conductive. I don't see any reliability issues with using it. It's in a non stressed, non load condition. It's just as if the plastic on the magnet ring was a little thicker.
I had a very similar problem with my Pertronix - according to the Tech help (which I must say is excellent) there is very little vertical tolerance in the spacing of the module with the Pertronix ignitors.
I actually used a thick rubber O-ring for a spacer - but whatever provides the correct spacing so that the top of the ignitor is flush with the top of the magnetic ring should work.