Hey all, Im going to be getting my head back from the shop on monday, and im not going to have them shave it at all, however i would like to try and bump compression a little. What size (smaller) headgasket can i use without having to change pushrod lengths? the guy at the shop said that it was ok to do between .010" and .015" (thousandths, i think thats the right decimal)... where do i go looking for a gasket that is that size? does anyone know?

Do you want steel or copper?
The adjustable rockers will help with a thinner gasket for sure. Personally, I'd go with a .020" gasket and just get new pushrods. Stiffer pushrods will help out a LOT in the higher RPM, just ask MadJack.




fortune cookie say:
better a delay than a disaster.

Well, where would i go about getting a .020" headgasket? Im all for this, however i dont know where to look... is this something that needs to be made custom or is there a manufacturer i can buy it from?

thanks notec id still be in the dark if you werent here to help me.... i suppose if theres ever anything that you need that i can do, feel free to ask..

thanks in advance again!

not sure where you can get a .020" headgasket, but i know you can get a cometic headgasket that is .030", which is a .010 smaller than factory, and is mls. that's the one i was planning on getting till i decided to go boost.



http://jbok.org

Matt, I wouldn't reccomend a thinner HG if you're planning to boost it. The stock HG is .055"( yeah, I was shocked to hear they were that thick!) You are better off running lower compression and a higher volume (not pressure) of boost. Commetic can make your HG in quite a few diffent thicknesses, to raise or lower your compression ratio, according to your needs.

the factory head gasket is .055"? wow, i never thought they were that thick. i was always told it was around .040"


http://jbok.org

Cometic can make a MLS in any thickness, the thicker the more it costs though (paid something like 110 for my .074"). SCE can also make a solid copper gasket in any thickness, and Flatout makes rubber coated copper in any thickness. There is a company that makes copper with built-in 'o-rings' to help sealing as well, but I don't remember who it was.
If you're going to be boosting less than 15 psi or so (you will need new pistons with more than that anyway), I'm still going to have to recommend a thinner headgasket, since it will help prevent detonation by tightening the quench and improving flame propagation. 9.5:1 is not an absurd ratio for boost (ECOs are 10:1 stock after all), and a highly polished combustion chamber will lower the ratio a little anyway.



fortune cookie say:
better a delay than a disaster.

Josh, My bad, your right. This would be a case where quench would be more beneficial than higher compression.

Matt, you would need to measure your piston-deck clearance. From there you will need to figure out how thick of a head gasket to get for a piston-to-head clearance of .035"-.040". This will give you ideal quench. Proper quench will do more for reducing detonation than lower compression and at the lower levels of boost that you're planning to use the added compression will net some minor gains.

MadJack wrote: Matt, you would need to measure your piston-deck clearance. From there you will need to figure out how thick of a head gasket to get for a piston-to-head clearance of .035"-.040". This will give you ideal quench.

Yes, measuring is VERY important. The .020" number I gave was assuming a .024" below deck piston (this number came from the back of Jack's memory, so double-checking would be a good idea). I also suggest .040" total clearance at the bare minimum if you're going to be using stock rods and pistons, .050" would be a safe choice (but not optimum by any means).
You can get multiple-layer steel gaskets in any thickness from Cometic, rubber coated copper in any thickness from Flatout, or solid copper in any thickness from SCE or Flatout.



fortune cookie say:
better a delay than a disaster.

Wow, too much information for one 5 minute setting!

Looks like i might be putting off doing this install for a bit more research.

It seems like everytime i feel like ive dug up all i need to get for infor, theres always something more which ends up with 100 more options...

im just glad to have guys like you, madjack, notec, that are happy to help out when needed.

back to the drawing board again for me! -- I'll be sure to let you guys know what I come up with.

Matt Linke wrote:Wow, too much information for one 5 minute setting!
Looks like i might be putting off doing this install for a bit more research.
It seems like everytime i feel like ive dug up all i need to get for infor, theres always something more which ends up with 100 more options...
back to the drawing board again for me! -- I'll be sure to let you guys know what I come up with.

Don't worry, I'm almost at 4 years on my engine build. There is always something more you can do, you just need to have a set plan before you start or you'll end up buying twice as many parts as you need (like I have, although it's more like 3 times more parts for me).



fortune cookie say:
better a delay than a disaster.