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Ol' Ron · 09-19-2021, 08:52 AM

Copper and aluminum creat an electrical current which caused the errosion of the aluminum. When you remove the heads after they have been on awhile, you can see where the aluminum has been removed. After beed blasting you can fill the area with Devon F, providing the fire ring is original. I was told by a fellow engine builder that painting the heads with Latex paint will insolate the two materials and prevent erosion. Might work, can't hurt.
As for the cam bearings? I don't usually measure the clearance of the cam bearings , However, back in the 90's someone, might have been Walt said he founf .006" clearance with a new bearing. (max is.003). Since then I've been checking all my cam bearings and have found several loose ones. Now when I receive a block in fair condition I measure the cam bearing before I remove them. If they check OK I leave them in the block if I'm not having it bake cleaned.
Gramps

09-19-2021, 08:52 AM	#60
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: Piston to head clearancing Copper and aluminum creat an electrical current which caused the errosion of the aluminum. When you remove the heads after they have been on awhile, you can see where the aluminum has been removed. After beed blasting you can fill the area with Devon F, providing the fire ring is original. I was told by a fellow engine builder that painting the heads with Latex paint will insolate the two materials and prevent erosion. Might work, can't hurt. As for the cam bearings? I don't usually measure the clearance of the cam bearings , However, back in the 90's someone, might have been Walt said he founf .006" clearance with a new bearing. (max is.003). Since then I've been checking all my cam bearings and have found several loose ones. Now when I receive a block in fair condition I measure the cam bearing before I remove them. If they check OK I leave them in the block if I'm not having it bake cleaned. Gramps