After about 20 hours the center carbon of the cap that makes contact with the rotor is all burned away. MSD 8560 distributor with 6m box, MSD coil and NGK plugs at .035 gap. Any ideas why the carbon burns away so quickly?

How much resistance in your plug wires? Are they good quality? BOB

they are MSD wires. not sure of the resistance but i purchased the whole set-up together. i would assume they gave me the right wires.

Do you have the polarity to the coil from the box correct. Seems like if it is wrong that will do something (and I cant remember what) but I know it wasnt good for it.
I have never seen that happen before.. Have you called the super friendly tech's at MSD?? They might know what the problem is.. they may not tell you but.. hey we all need a Dale Carinige class, right??

Good luck with this one.. I am sure someone has seen it..

Something is definitely wrong, I am not a fan of the Msd distributors in the first place. Also Msd claims that their wires are of the least resistance, maybe so . If the coil is grounding out this could cause you such problems. I ran the Msd distributors on my buddy's boat and removed them and went back to Thunderbolt IV because the msd's were not real marine distributors, and the mech. advance mechanisms were rusting and coming apart. PURE JUNK ! BBB

Resistance too high in a plug wire(s) would be first to check or change.
Check route of dist. and coil wires for crossing that may cause false triggers and mis-fires. This could also happen between plug wires.
Clean or replace cap and put a coating of di-electric grease on contacts.
Could be corrosion is your enemy here.

Mr. Gadgets, I'll have to check the polarity. The first cap burning up I attributed it to a bad cap. The second cap burning up tells me something is wrong.

MSD folks say to make sure the rotor tab is in contact with the cap. I did with the second cap, you could see where the rotor tab was making contact with the cap.

Thanks guys for your suggestions.

I have had the same problem in the past. The center tab on the rotor is not making good contact with the carbon center on the cap. This allows arcing between the two and erosion of the carbon. When you replace the cap and rotor bend the center tab on the rotor up a little to make sure it makes good contact.

Kris Vogt

ive heard the biggest problem with msd distributors is condensation because there is no breather hole. drilling a small hole in the cap lets it breath and lets the moisture out.

Try opening up the plug gap a little (maybe to .045) and see if that helps.

Dave