The points in my MSD distributor cap are wearing out after 6000 to 8000 km. I take the cap off and the points are all pitted and covered with a whiteish crusty material, which I imagine is carbon. I have a MSD Blaster Coil. Is this wear usual for these caps with a coil putting out such voltage? I remember seeing a comment in a Summit Racing catalogue by Professor Overdrive that high voltage coils are not really needed and to be used on engines with much higher compression and higher octane gasoline. Or was the professor referring to coils even more powerful that blaster coils?

 

Carbon is black, not white and crusty.

 

Double post.

 

I doubt that your cap is actually worn out.

Because high voltage arcs across the gap between the rotor and cap, some amount of metal transfer takes place between the cap contact and the contacts on the cap when this arc takes place. It's quite normal to see this. You'll see this even with stock coils.

 

I believe it's primarily aluminum oxide (the aluminum version of rust). The terminal points are usually made of some kind of aluminum alloy. They will get that crusty white stuff on them over time, which is normal. It can look pretty bad but still work just fine.

However, one of the things that makes this process worse is if the distributor isn't adequately vented. All those high voltage sparks cause a lot of ionization of the air under the the cap. Some distributors are worse than others for this, and I don't know why, but it's one of those oddball things that seems to plague some of them, but rarely cause a problem with others. Having a vent that allows some small amount of air exchange helps get rid of this ionization and slow down the process somewhat.

Factory small cap HEIs have a vent in the base with a screen over it. Make sure it's not crudded over with stuff.