Head Gasket

RET_COP · #1 (**permalink**) 12-05-2011, 02:37 PM

I'm trying to get my quench into the .045 range from .054. This would mean that I'll need a .030 thick gasket which no one makes off the shelf.
I'll be using it for aluminum heads on a cast iron block that has been decked in the original build. There will be no special surface prep just cleaned with a razor blade. I know Cometic can make one but I hear that it needs a smooth surface for sealing in the water jacket areas. I need some opinions please. The alternative is a felpro 1011-2 .039
Here is what I am looking at:
Quench .045 10.8:1 CR
Quench .054 10.6:1 CR
is the tighter quench more important to stave off any possibility detonation or is the lower CR with a wider quench better?
XE284H
359ci w
which one would you pick?
Thanks, Lou

blykins · #2 (**permalink**) 12-05-2011, 06:23 PM

Quench is better with any compression as it enhances flame travel and a more complete combustion.

My engines usually have a quench distance of .040-.050". Truthfully, you would probably never notice any difference between the two. What's just as important is that you eliminate all hot spots, sharp edges on pistons, etc. Those things can also contribute to detonation if the setup is not correct.

I take it that the pistons are .015" in the hole?

Barry_R · #3 (**permalink**) 12-05-2011, 06:36 PM

You are within the rational range with the normal Fel-Pro gasket - the point of diminishing returns. You'd never know the difference between the two combinations on a street oriented build. Better off spending the time and money to tune the rest of the package - tweaking the valve job, cam timing, maybe some dyno time etc...far bigger gains in other areas...

RET_COP · #4 (**permalink**) 12-05-2011, 06:49 PM

That would be on the money Brent, .015 in the hole.
Based on what you said, I'm probably going to stay where I am since I have the felpro gaskets and they will seal good for my application.
Good point on the sharp edges, I can take care of that. I believe I'm splitting hairs and over-thinking this. I just want to get it right.
When I do the engine over, someday, they won't be that deep in the hole

Thanks Brent,
Lou

blykins · #5 (**permalink**) 12-05-2011, 06:53 PM

Yes, there are a lot of variables there to get involved with.

I agree with you, and if you already have the gaskets, I would throw them on and start wrenching.