Got stuck Sat night a long way from home. The distributor rotor was cooked. All the ignition components have about 4K on them & things seemed to run pretty good. This is a Delco distributor in a V8 Packard and the same parts are pretty much found on lots of GM 50's cars. Cap looks mint, points look mint, I am running resistor plugs, modern resistor wires and I understand that this is a resistor rotor, maybe this is (one) of my probs? Anyone?
It's a problem now! Does it look like it's cooked, or broken, or what? did you find a new rotor and get it running again?
Looks broken to me....I see no discolorazation of the rotor.if burned,it would be black where it was burned.
Agree. That is not roasted, it's busted. You have some sort of clearance issue, or had before it resolved itself. Were the cap & rotor properly matched? I would remove the dizz, install a new rotor, and spin it with the cap in place to feel for clearance problems. Might have to go a little further to check for clearance. Maybe the rotor was not seated fully and that was the cause of the collision. Would be nice if it were as simple as that.
Ray Charles could see that it's not busted, zoom in on the pics. The plastic is deformed not broken away. If it was a clearance issue it would have never ran in the first place, this was a running driving engine with 4,000 miles.
Looks broken to me.... What's the missing piece or the inside of the cap look like? If this had gotten hot from an electrical issue, I'd expect to see some discoloration at the contact points and I don't see any. Most likely cause IMO if it isn't the usual problems (cap not on square, rotor not seated)? Sloppy bushings somewhere in the distributor that finally got just sloppy enough... Too much resistance in the ignition circuit will kill the coil if anything.
Helped a friend with an all stock 31 Ford. The tune-up parts were something else. When he fired it up it had a clicking sound like that of a ten speed bike while coasting. I can't say if the cap wasn't machine correctly or the rotor was to long. They just clashed.
Pretty typical rotor failure on this type of rotor. The resistor part is made in the rotor and failed after some miles.broken into the spark jumped across the gap making it larger every time you drove it until the gap was too large to run any more. Just get a new qualiy one from napa echlin. Let me know the application and I can look the number up in a old catalog. The Buick straight eights used the same rotor I believe.
Saw that on another Delco, except the coil wire was loose in the cap, & ate it's way out & down the side before it quit starting.
Saw that happen on old VW resistor rotors - same thing, resistor went Kaput and eventually the rotor grenades.
Great feedback guys. The inside of the cap was full of grey ash from the rotor burning up. Yes, back on the road, old car guys are BEST and I guess I owe some other poor car slob a big favor in the future. Tentative plan is to find a non resistor rotor. Or maybe the correct wires & plugs??
I'm trying to figure out the reason for the resistor. Radio suppression? Did the car come with no resistance plug wires? If it did you could change to resistor wires and dispense with the one in the rotor. Or just us a resistance coil wire.
I think with a new rotor,a soldering iron and a small piece of wire it could be byp***ed... My worry would be that high secondary burnt the resistor. Inspect the plug wire and inspect for open connections etc???
Bubba I once contacted you on a non topic vehicle. Also I had not noticed that the OP's rotor was resistored. Here's the connection. To much resistance and something is going to fail. My case a very difficult to get to ignition, not to mention expensive all because of the wrong plugs and wires.
To answer the original question .... it is possible for too much resistance to burn out ignition components. I have only seen it happen in cars with electronic ignition, that never had a tuneup, where the spark plugs were completely burned up . Eventually the excess resistance burned out the rest of the system. In your case IF the resistor was for ignition suppression on a car that came with non resistor, plain wire ignition wires it is possible the extra resistance of resistance wires did the damage especially if you had resistor plugs and they were gapped a little too wide. It would be necessary to know what plug wires and spark plugs were original equipment . Having said this I am not sure myself if it is possible but would be interesting to know the answer.
Ok lets talk about resistance. Theres primary (low voltage) resistance and theres secondary resistance ( high voltage). Each is a different story. The primary working rersistance is typically 3 ohms divided with a 1.5 ohm coil and a 1.5 ohm resistor. The divided parts lower the heat in the circuit . 3ohms in a 12 volt system would be approx 4 amps running current , however it will actually be lower based on the time constant required to build the coil and fire etc...this is the easy part and the part most often discussed. Now lets discuss secondary resistance ( a vastly different circuit) First of all the secondary is a open circuit with the rotor to cap gap and the actual spark plug gap. Thats two opens per cylinder. Add then the connections at the coil wire, distributor cap and spark plug ends and the possibilitys become larger for a problem to occur. Many manufactures allow 1000 ohms per foot of resistor/carbon secondary cable and that seems like a lot , however the coil fires and produces spark for only 2-3 mili-seconds jumping the set open gaps. This high voltage spark on a good system is approx 5,000/8000 volts and the coil could supply 50,000 volts if needed . The system will only respond ( go higher ) when needed. Acceleration changes the engine load requiring a higher voltage, air fuel mixtures (lean) need more voltage, wider plug gaps not only require more voltage but also more time in miliseconds to fire. Secondary resistance usually only becomes a problem with a open circuit making this voltage max out and burning up the connection where ever that may be.
I've never even seen or heard of a resistor rotor! Maybe I've been lucky. How common are they, when where they introduced, what common vehicles came with them?
Delco used these resistor rotors on the Buick straight eight cars, packards etc. VW used a resistor rotor as well. In fact rotors were changed a ton during the early 70s emissions cars etc. Delco made some rotors with "e" stamped on the tip for emissions and radio noise suppression .. You should always buy the rotor and cap from the same company....
Here is an interesting article on removing the resistor from VW rotors - could be applied to other systems as well http://www.huelsmann.us/bugman/RotorTech.html
Photo of the correct RR159 on the left & RR 157 on the right. What will likely happen is to install the #157 & keep the modern plugs & wires. I have pulled the Dizzy to blow out the ashes and it needs a rebuilt $85 Vacuum advance - similar to Caddys, Pontiacs & apparently obsolete?
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