Thicker head gaskets
- Thread starter Jeff Rand
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Donald McMullin
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- May 25, 2001
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What is your piston to head clearance?? I would be concerned about some reduction in the VE if your piston to head clearance is too great (uneven burn).
Deep Enough
Donald McMullin
Deep Enough
Donald McMullin
This block has a deck that is about .120" short vs stock and in an effort to get the intake to fit I will need to use a thicker gasket. Cometic makes the .078" gasket. They will also make a thinner intake gasket if I need one. I did a mock up using some iron heads and .078" shims with a stock intake and 1200 gaskets and it seem to fit O.K. Just wondering the downside to using the thicker gasket.
Jeff
Jeff
I guess the two things I'd be concerned about are squish and the rings coming closer to the top of the bore. Like DM said, you want the pistons to come as close as possible to the head to maximize the squish or turbulence, for the best combustion efficiency, short of actual contact. I don't know what clearance a high rpm stage II motor likes, but you might have to tweak your rod length and/or piston pin height to match up with your block and gasket to get this right (and I bet you've already checked this, huh? 
). Second, with a thick gasket you are going to need to stick the piston out of the block a little at tdc to get that squish, which means the top ring is going to be a little more exposed to the combustion and will see a little more heat. Might get a little more blowby at max boost, and might not last as long, but how much I can't even guess.
). Second, with a thick gasket you are going to need to stick the piston out of the block a little at tdc to get that squish, which means the top ring is going to be a little more exposed to the combustion and will see a little more heat. Might get a little more blowby at max boost, and might not last as long, but how much I can't even guess.Jeff, my block was .035 short on deck height, so the pistons were about .007 out of the bore. I had my rods offset bushed .030, and got the clearances right with a FelPro gasket. (I've got a headache right now, so don't ask me to re-check the math. It worked out.) Just a suggestion.
FreddieWilliams
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- May 26, 2001
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Jeff,
Since the piston is now lowered with the the offset bushed rods, why not use a standard head gaskets thickness and shave the intake manifold to fit. You can minimize the amount you need to shave off by using a thinner intake gasket as you mentioned above.
My Stage 1 had a very short deck as well and this is the route I went with.
Since the piston is now lowered with the the offset bushed rods, why not use a standard head gaskets thickness and shave the intake manifold to fit. You can minimize the amount you need to shave off by using a thinner intake gasket as you mentioned above.
My Stage 1 had a very short deck as well and this is the route I went with.
Freddie, I do not have the rods or pistons yet. The crank is 3.625" with BBC rod journals, so the rods will have to be custom. Also the piston can be made to what ever specs. I would like. I wonder how much the crown of the piston can protrude past the deck without encountering problems. The ring pack can also be adjusted. Do you guys think that if I get this project together and it makes some decent power; I might get a write up in Turbo mag.!
Jeff
FreddieWilliams
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- May 26, 2001
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Jeff,
You'll need to relocate your cam underneth the intake runnings, eliminate your pushrods, add three more spark plugs to each cylinder before you can get into that magazine.
Freddie, if there is a way, Iwill do it! Anything to get my picture into Turbo magazine.Originally posted by FreddieWilliams
Jeff,
You'll need to relocate your cam underneth the intake runnings, eliminate your pushrods, add three more spark plugs to each cylinder before you can get into that magazine.
Jeff
