Big Block Olds ??

[TraceZ]

My father has a 455 in his 1983 Hurst/Olds. He is having a problem getting the intake manifold to seal. The "stock" gaskets are a metal valey pan and rubber gaskets for the front and rear. He tried using the metal valey pan twice but was not able to get it to seal either time, ending up with water in his oil. A long time Olds mechanic told him it was common for torque to twist those blocks and cause the intake to not seat properly and leak. He recommended a set of thicker gaskets just for that problem and Dad was able to get the water leaks to stop that way.

Here is the problem-

Now, because the intake sits up higher with the thinker gaskets, the ends are leaking oil. Specifically the rear, right down over the bell housing. He has tried sealing it with permatex and that just pushed right out in a matter of months. He tried using the factory rubber gaskets, but they are not thick enough to work.

How should he get this to seal?? He is getting really tired of reinstalling the stupid intake manifold. Any ideas are appreciated.

[DeWynter]

Ive been told not to ever use the rubber gaskets at the back of the block and to just clean up the block good and use RVT Silicone to build a custom gasket. That way if the gasket is to small (from bigger gaskets) or to big (from milling the block)its always a perfect fit. I always use it on 350s

[Joe 1320]

Unfortunately the best proceedure is to have the block decked. Short of that, the rear of the block could be sealed with high temp silicone. Do not use gaskets here, but a tall 1/4 wide bead, allowed to set until it skins before assembly should work. The oil isn't under pressure there, you're merely sealing the rear of the intake. The key is to allow the silicone to "skin"..... where the outer surface starts to harden before the inside cures. With a tall enough bead, there should be no problem.

[RangerBob]

Let the silicone set up 24 hours before installing the intake.

Bob

[TraceZ]

Let the silicone set up 24 hours before installing the intake.

Bob

What do you think about laying a big bead on the block, letting it harden for 24 hours, then skimming the intake with a thin bead before applying?

Assuming both surfaces are clean and ruffed up with emery paper beforehand..

[aschroeger]

Old man

Trace

The old man is finally fed up with that leak huh? I had bets in that he'd sell it before he fixed it!!!

BTW: Brian and I are going to go to WIR saturday afternoon to watch the drags, and will probably stop in by Troy's for a bit afterwards.
-A