[Verdoro 68]

Originally Posted by Singleton

Was any type of anerobic sealant used between the main cap and the block surface before bolting down? Oil can migrate there also.

Originally Posted by mgarblik

Excellent point and that can be a bitch of a leak to find. On a recent IAII aluminum engine< I had a leak there with the anerobic sealer in the joint. Only a smoke test would find it. With the flywheel off and the smoke on, it was roaring smoke out of that interface on both sides, very obvious. I sealed it with RTV from the outside and retested. Leak gone. Pontiacs are very difficult to seal 100%. A real challenge.

Regarding the main cap mating surface, I used a smudge of Right Stuff black RTV. Is there something better I should have used?

[mgarblik]

Originally Posted by Verdoro 68

Regarding the main cap mating surface, I used a smudge of Right Stuff black RTV. Is there something better I should have used?

I personally don't use "Rite Stuff" very often. It is a rock hard setting RTV. In that application, it would probably work fine. Just a tiny dab. If not leaking there, I would leave it. If you end up having to remove the main cap for a main seal, the recommended sealer for that area is an anerobic, (seals without air), gasket replacement gel. Like Locktite 515 or similar. It is a very thin red gel. It is made specifically to go between two machined surfaces and sets-up when air is removed. My only gripe with "Right Stuff" is it is so hard setting, it's nearly impossible to remove a sheet metal part sealed with it without bending the hell out of an oil pan valve cover or lifter cover. I just like the softer setting RTV's which seem to work just fine for me. My favorite is Valco RTV made in Cincinnati, OH. Second favorite would be the Permatex Ultra series stuff. Everyone has their favorite.