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I recently had my intake manifold off of my chevy small block. When I put it back on I used new gaskets mixed with high temp silicone gasket.
The front rubber gasket that gos along the block apparently didnt seal to well and it blew completly out and now I am loosing anti freese through the hole??
Any way im swapping my intake out for a Weiand this weekend and was wondering if there is any special process I need to follow and what is a good silcone sealer to use?
In my opinion,,using silicon based sealers with rubber on high pressure zones is a bad idea to begin with, because silicon will not bond with rubber gasket material well enough for a pressure application.
I try not to use any gasket GOOPS or Compounds to begin with.
If the machined surface is mated properly you shouldn't need anything except some high tack gasket glue to hold in place as you are tightening your bolts.
It's possible that your manifold is warped, and therefore preventing a good seal.
Before putting your new intake in place,,,try putting a straight edge up against the mating surfaces to make sure they are truly flat, and not deformed, or burred,,even a little piece of old gasket material left behind on the mating suface will prevent a good seal.
Quote:
Originally posted by nystreetscene
I recently had my intake manifold off of my chevy small block. When I put it back on I used new gaskets mixed with high temp silicone gasket.
The front rubber gasket that gos along the block apparently didnt seal to well and it blew completly out and now I am loosing anti freese through the hole??
Any way im swapping my intake out for a Weiand this weekend and was wondering if there is any special process I need to follow and what is a good silcone sealer to use?
I don't have a problem with using black hi-temp silicone sealer in the intake manifold area. Of course, I always use a PCV valve to keep crankcase pressure down.
Some intake manifold gasket kits are 4-piece. One pair for the heads, and one pair for the engine block front and rear rails. On those, I just drop the gaskets in place, then put 4 dabs of black silicone at the corners where the gaskets meet.
The manifold kit on my new crate moter had only two gaskets - for the heads. The front and rear block rails were sealed with a bead of black silicone.
I've never had either method fail - as long as I used good gaskets, and the mating surfaces were not warped.
I through away the rubber gaskets and just put a 1/4 inch bead of silicone on the ends. Never had a problem with this and edelbrock recommend this and also seen this recommended elsewhere, can't remember.
Just for general interest, If your going to use a silicone sealer for the end seals, or anything else, a GREAT product is a GE Silicones primer, part number SS4004. It primes any surface and allows the silicone to adhear to the surface. We also use it on head/intake surfaces that have inprinted silicone gaskets. It really works great, but must be purchaced from a GE dealer/wholesaler direct. Cost is about $25.00 for a 16 oz bottle.
Throw away the rubber front and rear gaskets. Jegs sells a can of black sealer called The Right Stuff. A little expensive but well worth it.
Kevin