Anyone knows of a Newsgroup where to post questions about car problems? I have taken mine to at least 6 shops and they can only guess. I have to replace the distributor rotor every one thousand miles. Sometimes less.(Every 3 weeks) The maintenance schedule says between 30 thousand and
60 thousand. The electric arc digs a hole thru the rotor plastic body every time. I have bought genuine parts (rotors and distributor caps) from the car dealer (most expensive) with no success I don't wanna start replacing components at random. They say it may be the coil, others the condensor, others say my truck does not have a condensor or a coil, ???? Its a 91 Chevy pick-up.
Sounds like the rotor is doing some wide arc welding. Timer located on the distributor shaft, just under the distributor rotor can loosen up and change position. Rotor is out of sync with the distributor contacts. Tries to fire too soon/late and current increases trying to jump too large of a gap... stuff burns.
In alt.home.repair on Fri, 1 Oct 2004 02:45:00 -0500 "digitalage" posted:
P&M, please reply via the newsgroup.
You can probably find a group just for Chevy or just for GM. In this case, the parts are not unique to trucks, and more people may read the broader one.
If you're not happy with the ng's, try Yahoo lists (known as groups on their home page,
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There are far more lists, just at Yahoo, than on Usenet, and they get very specific. IIRC there are 4 groups (lists, really) for Chrysler LeBaron's alone, and one for souped up LeBarons. Or maybe that was another car.
People who mostly read lists don't know how to post very well, but any port in a storm.
As you have figured out, the problem is not the rotor.
When cars had condensors, the condensor might have done this. In fact your problem is related to the purpose of the condensor, to provide when the distributor points start to open an easier path for the ignition primary current than jumping the gap in the partly open points. When the points are fully open, 12 volts won't jump the gap, but when they have just started, and are only open a micron or two or
10, the current would spark across the points, and transfer metal from one point to the other. By seeing which point was getting bigger, you could tell if the condensor had too much capacitance or two little. (although I think in practice it was always too little)
Points started disappearing between 1973 and 1984. I didn't have any cars from in between years.
I don't know your car, and you may not have a coil either, but you probably do. Coils need replacing when the car won't start in wet weather, along with the sparkplug wires. (I always replace just the wires and then the coil, but I'm a cheapskate, and if I'm late to work it's no big deal.) Believe it or not, eventually coils start to soak up humidity, I guess it is, on rainy days. Hmmm, if I recall correctly, in an emergency, you can dry the coil off in the oven, set at low, 170 degrees? Low enough it won't catch fire. I keep my previous coil in the trunk. After it would have dried out, I wrapped in Saran Wrap, so it should be dry, if my current coil ever fails.
But I don't think it is ruining your rotor. Ask people who know more than I.
Meirman
If emailing, please let me know whether or not you are posting the same letter.
I bet you have a bad (specifically an open) plug wire... the coil has to up it's secondary firing voltage to jump both the gaps in the plug, and the bum wire. (The 'secondary' part of the ignition system is everything dealing with high voltages, where the low voltage ignition system components are commonly referred to as the 'primary' system) The gap in the wire keeps eroding bigger and bigger over time. The abnormally high secondary voltage is exceeding the dielectric strength of your rotor, a common weak link in GM distributors. You'll probably start going through coils, and possibly distributor caps if you don't fix it soon.
If you can get someone to look at your secondary ignition system with a scope, it'll stick out like a sore thumb. An Ohmmeter check of the wires will probably also find which one. Or just put on a set of wires... I don't think you need to get them from the dealer, but don't get bottom end econo-budget wires either. Be sure to route them correctly...
If this turn's out to be the case, and I think it will... take bad wire and very carefully split it in two the long way. You'll find the open (probably at the plug end), it may be an inch or more long.
If stock, I think your truck has a Delco HEI (High Energy Ignition) distributor, that does have a condenser... but it's purpose is mostly to keep ignition noise out of the radio. The older 'point type' non electronic ignition systems had a condenser too, but it was to keep point arcing in check. However, either of these systems with a bad condenser wouldn't zap distributor rotors as you describe.
This isn't as big an issue as in years past, but you still see it once in a while. It's why they always tell you to treat plug wires gently, and to only pull them off by the boots.
Let us know how it goes.
Good Luck!
Erik
PS, Another good investment is a real GM factory shop manual for your truck... Google around a little and you'll find one.
PPS, And if you ever buy a new car/truck, as part of the negotiation process, get the dealer to throw in a set of shop manuals... now days they come in several volumes, so be sure to get them all.
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