Weird distributor problem. HELP!!

[mhicks]

I have a problem with my distributor. I bought it brand new from Jegs about a year and a half ago. I put it in the same time I installed my crate engine from Jegs. I bought a high performance GM distributor. Ever since I had it, it hasn’t worked right. Sometimes it would go for a couple of days and sometimes a month but it would not start. Seemed like no fire to the plugs or distributor. Once when it wouldn’t start I ran a wire straight to the battery and that did not fix it. I ended up buying a new module, took a couple of modules out of other distributors and kept them with me. Every time I had a problem when it didn’t start I would change it out and that would fix it. Then I reused them over and over and each time it seemed to fix the problem. So that eliminated the module. Since then I have replaced the coil, the wiring inside and outside. Of course the usual rotor and cap. A couple of weeks ago it died on the way to work. Didn’t have time to mess with it until after work. I pulled the cap off and the little flat piece of metal on the rotor was burned up. The last ¾ of an inch near the center was gone. Got a new cap and rotor and that fixed it. I got to looking at the old cap and the center button was melted into the cap and the plastic around the button was all melted. A few months ago I figured out that when it wouldn’t start I could just pull the cap off and rub my finger on the metal on the rotor near the middle and put the cap back on and it would fire up. Since then I figured out that sometimes all I have to do is remove the distributor cap and put it back on and it fires right up. I have put several new caps and rotors on it in the last year and a half. I have tried several different brands. I have bought the best the store has al the way down to the cheapest and have yet to figure out what is causing this problem. The truck is a ’73 Chevy with a 350 in it. Does anybody have any clue as to what can be causing this? It is sure getting old.

[slug]

are you running a high output hei coil?? or a msd box?? if you are try eliminating these by going with a stock coil, see if that helps.

[mhicks]

No, just the stock coil on top of the ditributor cap. Power to it from the fuse box. '73 did not have electronic ignition. I upgraded to electronic ignition and just ran a wire to fuse box.

[sjarrett71]

This idea is WAY out there but are you making sure there is dielectric grease on the botom of the module? It may be overheating. If that's a stupid suggestion, please disregard.

[us111]

grease is not a bad suggestion at all,it will definitely cause a problem
if not used.also i read somewhere not to use the old wire going to the distributor because it was a resistance wire {i think) always replace all
the way with new.but either way things sound like they are overheating
and causing your problem.grease is certainly a starting point.

[joeymarkgraf]

Check your voltage and wiring going to the distributor, maybe you might have a bad alternator causing over voltage problems? Just a stab in the dark, hope it helps.

[mhicks]

Nope, I did that. Also, it doesn't seem to have anything to do with temperature. At one point I was just putting the old ones back n and they worked fine. At this point I have found that just taking off the cap and putting it back on makes it work, could be for a day or a week or two. I think it has something to do with the contact between the button on the ditributor cap and the metal on the rotor. Like the cap is being pressed down too hard against the rotor.

[mhicks]

ttt

[LONGHAIR]

Like the cap is being pressed down too hard against the rotor.

It is more likely that the cap is too far from the rotor. If the button on the bottom of the coil is not making solid contact with the spring-tab of the rotor, it will cause arching. Since you stated that the center of the cap and rotor were "melted", I would look there. This is supposed to be a solid connection, the only arching is at the rotor to cap terminal points (plug wires) and of course the sparkplugs.
This is all assuming proper in-put voltage and good plug wires. If the wires are faulty that greater resistance impacts everything.

[1970pelle]

All good points given.Double check the cap to be sure the coil contact/spring thing.I think they call it a HEI Bushing. And the rubber round spacer.Are they installed correctly?When you said you checked power supply voltage.Did you us a test lite or DVOM?Double check with DVOM for true 12v.And wire harness with the capacitor possible issue there?They only cost about 8 bucks.I just replaced mine recently.Thats all I can think to check.Keep picking away at it.In the end it will be something right in front of you.That's what happens most of the time on my issues.

[mhicks]

I have tried bending the contact tab/spring up towards the cap a few times but problem continues. I used a Fluke meter when testing the voltage. I don't have anything inline with the power going to the distributor. I have a wire going from the fuse box straight out to it. When I first got the motor installed a couple of years ago I hooked the new distributor to the original wire. It is a '73 so it did not have electronic ignition. I changed it over when I did the new crate motor and new distriutor. After having problems with it not starting I then ran a new wire to it from the fuse box.
I am beginning to think there was a screw up in the machining somewhere and the cap is too close to the rotor? You can't tell once the cap is on. Maybe slice a cap in half so I can see how it matches up? I have had about enough of it. Thanks for the ideas everybody. Anymore would be welcomed.

[LONGHAIR]

Are you sure that the cap/coil is assembled correctly? The button goes in first, washer, then coil and the ground strap.

[Square84]

i work for a parts store we had guy come in several times burning up modules ended up being he forgot to put the ground strap on the coil to the coil cover bolt.

[MylilBowTie]

Check the resistance in the spark plug wires. Might have a bad one.