lost fire

Maverick

1955 Hudson Hornet, 308 twin H, Pertronix ignition and coil, has been running great, no problems and just sold the car. The buyer has been running it with no problems then yesterday went to back out of his driveway and the engine quit. It has gas and new plugs, I took the distributor cap off and cranked the engine and when the rotor comes around to where it is pointing at the cap it fires that cylinder even though the cap is off. If I move the cap it fires on the new position but when I put the cap back on it won't fire on any of the plugs. We will replace the rotor and cap tomorrow but I have never seen an engine fire with the cap off. Has anyone experienced this before? Or any suggestions on what I should be looking for. I would suspect the coil but it fires with the cap off so I doubt if the coil has gone bad. I would appreciate any help on what I should be looking for.

Maverick

Okay, when I remove the cap and let it hang next to the distributor the rotor comes around and points where it is hanging, which ever wire it is pointing at fires, if I let it hang in another spot it will fire when it points at that spot on the cap. The cap is not over the rotor. This pertronix unit has been on the car since 2007 without any issues. I will see tomorrow when I replace the cap and rotor. I don't think I've ever seen a distributor fail like this. I'm hoping the timing chain didn't break. I'll know tomorrow. Did this explanation better describe what is going on?

Maverick

Sorry, this is hard to explain, it is not jumping to the wire, it is jumping to the cap and there is no spark visible when it jumps. I can replace the plug wires even though they are relatively new. It seems as though the cap has broken down but why would it still not fire when the cap was on the distributor?

EdHudson

That is a very strange problem. Try removing the coil wire, then the rotor and see what happens. You could try moving the hanging cap to a different position and see what happens. I'm not familiar with the pertronix, but my first guess is the cap is bad, and #2 guess is it's the pertronix. You could always look for the random spark in the dark.

Maverick

where ever you put the cap the plug fires when the rotor points at it. I can hear the distributor fire but I don't see the spark but I haven't tried it in the dark. I'll know more when we put the new cap on

Glowplug

Guessing long distance... Your cap is a carbon track which is less resistance than the plug wires. When the cap is placed next to the distributor the coil is discharging to One plug through the cap! The cap is designed to prevent this from happening

Maverick

do you think the wires are all bad? It's not the coil wire or it wouldn't discharge to the cap. I'm going now to put the new cap on and I'll post latter what I find out.

Maverick

changed the rotor and cap, car runs like a top. New plugs also just to cover all bases. I'm guessing it was the cap but I don't care which it was as long as it's running again. Thanks for the help, my next questions won't be so easy

Glowplug

Thanks for the update Maverick