When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Doing a tip to manual conversion - see other thread.
While I have the engine out I'm doing a quick change of valve covers, valve cover gaskets, camchain housing gaskets etc.
When I took off the camchain covers the face of the camchain housing was a mess. Looks like someone thought that gasket goo was required. Anyway, I cleaned up the faces and they were very pitted. So I cleaned them right back to metal. Looks pretty bad, see photos.
So questions:
1. Is pitting normal?
2. Will the new gasket seal even with the pitting?
3. Can the camchain housing be sanded down diy or resurfaced professionally?
And, slightly different question- has anyone considered having the cam chain housing and cover painted or powder coated?
I’ve replaced chain cover gaskets on a number of 993s over the years. It’s never easy to remove the baked-on residue from the mating surface. I scrape it as cleanly as possible and wipe it with a solvent before installing the new gaskets, etc.
The pitting is quite common from what I’ve seen. Use Curil T on both sides of the gasket.
I went with satin black, not sure on the spec. I cannot speak to the long term yet as I just did it last week. As for heat, the temp won't be any higher than your oil temp ever gets.
They are magnesium and will easily pit if moisture is allowed to attack the surface. You need to at a min paint the surface before doing anything otherwise it will only get worse. Cerakote is a good modern approach but that would require removal of the timing chain boxes. I would not powder coat magnesium since it varies greatly depending on who does the work and builds up a thick layer. Cerakote is far more durable and thinner. It is used on most weapons these days.
You have exposed magnesium which must be addressed. The corrosion is pretty severe for a matting surface. I normally don't use anything, however If i were, Curil T would be what I use and in your case might help with the pitting. You need to at a min use an etching primer and paint that allowing it to cure for a while before closing up anything.
I just cleaned mine. I used a plastic scraper designed to remove wheel weights to remove the old rubber that bonded to the mating surface. This way it doesn't scratch or expose the magnesium although there are slight signs of pitting. The outside was fine I just cleaned with penetrating oil and they look like new.