[ALLT4]

Why is it you can take every precaution, be as clean as possible (downright antiseptic) use the best sealants known to mankind, make a bead that looks like a straw laying there and your intake still leaks around the china walls? Or is it due to using synthetic oil and it's ability to seep better than regular oil? I just give up, I'm not talking oil running everywhere not even enough to check the level, just discolored on the head edges and down the front of the block a few centimeters.

I think it's impossible even from the factory.

 

[TuBaDuB]

Synthetic oil is like termites it will find any place to leak if it can. Not that termites leak but they can find the smallest minute spots to get in your house. I've used the bead method on the front and rear of the manifold before. But I currently use a thin cork gasket with silicone. No leaks or oil residue in the front or back of the block. Now since I said that it's going leak.

 

[veno]

I know how ya feel..... first 350 I built for the nova.. I completely assembled on the stand.... made absolutely sure I took diligent care in sealing the ends as I did not want the dreaded rear oil leak that plagues so many..... sure enough... I had the same leak....

after removing the intake once more and cleaning everything with brake parts cleaner once more.....it sealed till I cracked a piston.... then the 385 was built.. now i broke a rocker.. so now I installed a set of crower stainless rockers.....

never ending battle with high HP and ...............:devil: a heavy right foot!

 

[6367Rick]

I have used "The right stuff" for valve covers and found it pretty good. I am going to try it on the intake when it gets back from the coaters. I also have had good luck with "Form a gasket" used lightly with cork. I have my fingers crossed.

 

[Paul Wright]

I agree that the rear china wall is tough to seal properly, but it can be done.
I guess it just takes practice and experience. I think the problems come from when the intake is set on the engine. The intake must go straight on with minimum of movement. Install all the bolts by hand but don't tighten. Check for gaps. The weight of the intake should cause the bead to stick to both the manifold and the block.
The bead must then partially cure before torque sequence to allow it have preload "springiness". If you just tighten it down right away, the bead squishes out.

I worked in the dyno department for awhile and had to R&R a lot of intakes. Once you get the process, it becomes second nature.