Melted Distributor Rotor

My Rotor melted AGAIN. I've searched for and found other threads on this issue but none of them have an answer to why this is happening. I've replaced the cap and rotor with high quality parts, factory, stock, and cheapos from AZ but they all eventually melt down after about 1 year in service. I replaced the coil and it did not help. New wires and plugs too.

Right before the melt down, it gets difficult to start, I notice a sharp drop in MPG and it starts to hesitate (cut off) at highway speeds. It's never stranded me becasue I always catch it and replace parts before it gets too bad.

I'm thinking the computer thinks (or knows) the fuel/air mix is Rich and is telling the coil to juice up the spark. The tail pipe also shows A LOT of carbon in the pipe - another indication that the mixture IS too rich. I don't want to start replacing parts - they get expensive quickly.

Does anyone know if these two issues are related (rich mix and melted rotor) or how to resove this problem? Anyone who has had this problem and permanently solved it please chime in. I'm getting tired of replacing these things

Thanks!!

Rich mixture and rotor meltdown should not be related. The computer does not change the strength of the spark. It is also pretty wierd for the rotor to make it for a year, and then melt down. What acrually melts? Any chance for a picture? Have you checked for excessive play of the distribtuor shaft? The bushings can wear out in the distributor housing. Year and motor type would also help diagnosis. What temperature do you run at?

Check the center contact in your distributor cap and make sure it's making good contact with the rotor button and not binding. If it's not contacting correctly it can arc.


Here a link that describes your problem:

http://www.mightyautoparts.com/pdf/articles/tt70.pdf

I've had this happen in other vehicle types and it was caused by worn distributor shaft bearing/bushing. Pull the distributor and try to turn the shaft by hand- it should spin freely with little to no resistance. If it is tight, I'd replace it and check for possible low oil pressure no feeding the shaft any oil.

You can try to put a little bit of white lithium grease on the small shaft that the rotor slides down on. Replacement rotors used to always come with a little tiny packet of it but they don't anymore. Your service manual probably recomends this too. I do not know if this is your problem but it's cheap and it won't hurt. Good luck.

The problem is likely the way the replacements are made. You can't cheap on a Cap and Rotor set, the rotor will fail. Sure, it could be bad bearings, but that is not what I encountered.

Replace both the Cap and Rotor, not just one. The Cap gets all tracked up, so just replace it. Replace with parts made by Standard Ignition or if you can get them though your OEM, do that