Packard Forum Index » V-8 (1955-56)

Recently I was asked to consult on two different distributor problems caused by the same mistake.

The later GM Delco distributor cap can be made to sit on the Packard Delco distributor, but it won't function correctly.

In the first instance, first the rotor hit the inside of the distributor and broke. The replacement rotor then broke the cap.

This happens because the later GM distributor cap is .100" larger inside the mounting area. This allows for enough misalignment for the rotor to hit.

In the second, the car was running roughly and misfiring. The late GM cap isn't properly indexed to the Packard distributor cam and when the points opened, the rotor was between poles in the cap. The spark could go either way.

Bottom line - make sure to buy the correct cap. It should fit tightly with absolutely no play on the body of the distributor.

jack vines

The spark could go either way

Jack, glad you pointed this out, great advice is to always check replacement parts carefully against the original or previously functioning part before installing. I have a friend with a 41 LeBaron Sport Phaeton who got an incorrect ignition rotor installed. First time it backfired it damaged the carburetor and split the air filter drum wide open at the seam. Without giving thought to why it happened nothing else was done but to repair the damage. Next time it backfired it blew the exhaust system halfway across the garage. About $2000 in repairs for an incorrect $10 part.