This may be a crazy theory but I have heard some people talk about stacking two head gaskets on top of each other to try and lower compression. I have never heard anyone say they ever tried it or that they have been succesful in doing this. I know I can buy thicker head gaskets but can't get any good info on which ones work the best and hold together the best, Plus I have a STACK of about 20 Fel-Pro head gaskets. My comp is about 9.5 right now and I would like to see it closer to 8.5. By the way this is a L31 (Vortec) motor with a blow through turbo carb setup.

 

On a turbo engine I would think the last thing you'd want to do is use 2 gaskets. That would be an invitation to a problem. Many people who use boost have enough problems with blowing out head gaskets.

 

Hot Rod awhile back did have a company that was making spacers for the head gaskets. LOL, they used one to go from a 11+ to 9ish compression. They required special chemical cut on the block though.

Another thing to mention is when you mess with your spacing it can actually cause more problems than good. It can actually increase your chances of getting spark knock even with a lower compression. If I can I'll try pulling the quote of the Corky Bell book about this later tonight.

 

I have read about all the effects of thicker gaskets on quench and what not but, must people say that on a boosted engine quech is not as important because the air in the cylinder is so much more dense than on a NA motor. Plus my pistons have a round dish that takes up almost the complete top of the piston so I don't have a quench area anyways.....

 

I'll try digging around for that link to the head gasket spacers for you then. Best of luck!

 

You can get copper head gaskets in any thickness you want.

 

Copper gaskets are a pain to seal. I had some for a while on my o-ringed block and I couldn't get the coolent leaks stopped. Even using Hylomar didn't work.

 

The spacers I was thinking of were offered from 0.025 up to 0.125 or so.

 

Try Cometic gaskets. They will make custom head gaskets different thicknesses to order ( www.cometic.com).
hope this helps

 

Thanks RWB____s!

You just saved me a whole lot of looking for that name. Yeah that's the company that offers the head gasket spacers.

 

Nitro seal gaskets and open the chamers up. Problem solved and flow increased.

 

Before you laugh too loud at stacking gaskets, the factory Mopar Chevy and I think Ford as well used to do this in the early 60's.

 

This procedure was done in thelatest issue of Engine Masters. They basicaly tested the effects of changing the CR to see if there was any HP gain of loss. They stacked a totalof 4 head gaskets to go from the 11.0:1 to 8.0:1.They lost 60hp doing this. They used Milidon dead soft copper gaskets.They also O ringed the block. They also had to stack multiple intake gaskets since rasiing the heads ould end up misaligning the bolt holes.
.

 

If you were to intergrate a water/alcohol injection system into your turbo project you would not have to lower the compression ratio or retard the timing near as much.

 

holy crap did you see that 727 cube monster!!!

 

It would probably be easier to pull the heads and hog out the combustion chambers with a die grinder to make them bigger. That would lower your compression ratio.

 

I would be against staking of the head gaskets myself. no proof on it but it seems like others have said an invite to disaster.

also even on a boosted motor with those denser mixtures you still need quench in there if you want to get decent octane tolerance and resistance to detonation.

this way you get a nice good flame front rather then some choppy lame *** flame front like a motor with little to no quench area is going to give you.

 

quench means ALOT no matter if it's a 7.5:1 stock engine, or a 6000 hp blown top fuel drag engine.

The benifits from a tight quench height is great. You gain power, you gain compression, and you fight away detonation

With 2 engines, built the same, the same compression, only diff one had a wide (add number of your pick) .060" quench and the other one has a .030-.045" quench height.

I bet you money, the one with the wide quench will need more octane, or less timing that the tight quench engine, to keep it out of detonation.

Then you come to stacking gaskets.. Well more gaskets there, more rish you run of one of them not sealing, blowing, etc

With boost, head sealing is a major thing. With higher levels of boost, you can lift the heads up off the block, if you don't run studs. Thats with very high boost levels though. My point to is is, if high boost can do that, well mild boost could find its way through a stack of gaskets