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Old 04-03-2002, 09:02 PM
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MoPaul MoPaul is offline
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Question Double-up head gaskets for lower CR?

A friend told me that he has heard of doubling up on the head gaskets to lower compression ratio. This doesn't seem like a good idea, but for someone whose block has been decked and heads have been milled and is now seeking pump gas compression levels, would it be a good idea?
Please tell me if I am wrong, or why I am right about this being a bad idea.
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Old 04-03-2002, 09:42 PM
Tarrbabe Tarrbabe is offline
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Default Stacked headgaskets?

I'd rather play with rattle snakes. If you want to lower your compression and have some sence of confidence without changing pistons, order a set of copper head gaskets. My local machinest says they can be ordered in diffrent thickness's to help out with this problem. You will need to figure out what thickness you need to get the results you want.
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Old 04-03-2002, 11:57 PM
djswwg djswwg is offline
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Although I agree completely with Tarrbabe in theory, I once used doubled up felpro headgaskets on my 440 for the exact reason you describe. I had zero problems with the engine, but it did not cut the compression enough to make a difference with ping on the street anyway. So the next time I took it apart I went back to one gasket.............djs
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Old 04-04-2002, 01:06 AM
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SpeedSleaze SpeedSleaze is offline
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MP has a .060" shim that's supposed to drop your CR about .5 pt I believe.
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Old 04-04-2002, 01:15 AM
Tarrbabe Tarrbabe is offline
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I had forgot that MP had those. It has been so long since I had heard of them but I red faced, I should have remembered.
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Old 04-04-2002, 05:58 AM
SB Racer SB Racer is offline
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Biggrin Steelshim

I've used Mopars steel shims to lower CR in an relatively tight SB combination. I just sprayed them with VHT copper gasket sealer before installation, the shim against the block and gasket into top of the shim. Worked just fine without leaks.

TeRo
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Old 04-04-2002, 09:33 AM
turbododge turbododge is offline
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I machined a .059 steel shim and used a composition head gasket on each side to lower the compression on a 2 liter Ford turbo engine I built. It held fine. You might be able to do the same thing by using a copper head gasket between two standard ones. I wouln't stack to composition gaskets on each other.
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Old 04-05-2002, 12:07 AM
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rumblefish360 rumblefish360 is offline
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I used the MoPar S/B shim without a problem for quit some time. You can combine the .060 head shim with a .054 Fel-Pro head gasket. Thats .094 thick without the steel shims recomended sealent on it. The sealent I used said it can give up to .010 thick coat. Yea, you gotta use a thick coating for that. But it's possible.

Used with a .038 gasket, it's good for about a 1pt. drop. The gasket used is key. Brush up on your math...
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Old 04-06-2002, 09:16 AM
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MoPaul MoPaul is offline
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Many thanks to all. I knew they had a shim for the 2.2 but didn't see one for a sb. I don't have any intention of doing this, by any means. The idea seemed "wrong" to me and I was just curious.
Again, I thank you.
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