<VV> Ignition Help

[Larry Forman]

Hi Dennis,
Here are some thoughts:
1. First take a cylinder compression check or (better) a cylinder leakdown check.  No amount of tuning or parts replacement will correct a holed piston.  Know what you are dealing with on the engine basics first.
2. Second, I like to make the ignition system bullet proof next.  If so, you are SO ahead of the process.  New cap, rotor, ignition wires (Seth's or other quality Corvair wires) AND Bosch 7502, aka W8AC Super Copper plugs, NOT platinums.  There are then other things to check, like voltage to the coil, wiring the Ignitor I to 12 volts directly, checking vacuum advance operation and "tuning" it by compressing the end, and finally checking operation of the mechanical advance.  If all that is OK, you are 90% of the way home.
3. For the ignition coil, ALWAYS replace a stock coil, just because, and I like to carry a spare.  If an ignition coil goes out, you are dead in the water, like a dead fuel pump.  Replacing one of those can be done roadside in 5 minutes.  Swapping one in or out to diagnose is faster than posting on VV!
4. Watch for any signs of overheating.  You are correct that overheating could cause this.  I had one 66 that had an open smog pump port and caused the engine to overheat.  A simple cover plate fixed the overheating.  You could use a simple temp probe or an under plug sender to determine CHT temps for diagnosis.  If it overheats and then is OK after a few minutes of idling with the engine hood up, that might be your issue.

Let us know what you find as the reason.

Larry