Head Gasket?, what head gasket Options

[d0w0rkS0n]

Hey guys, almost ready to boost my 7a. i noticed the Head gasket size is 81mm. all the head gaskets im finding is 87mm and 89mm from Cometic. what head gasket do yall recommend? anything else? what should i do?



any adviced will be greatly appreciated.

thanks!


Allen

[hurley97]

Theoretically thicker is better if you're planning on boosting. However, using a composite headgasket instead of a metal one makes for more of a chance for the higher pressure in the cylinders to blow out the headgasket. IIRC OOBE had an aftermarket HG that was composite material that he blew out. That Cometic one sounds ok though.

I had the parts dept at work order the 4A HG just so I could compare the two. With the 4AGZE HG all the oil passages lined up just fine but all the coolant jackets were off (or it was the other way around, but I think that's right). The ones that were off did overlap so it's not like it wouldn't flow anything through it, it just would only flow say 50-60% and the flow would be disrupted by the bottleneck. I'm sure it would work just fine but I put a lot of time and money into rebuilding my engine and wasn't about to risk that when the stock HG would be just fine if not a little better. Plus changing the CR isn't necessary, just a plus if you can. I chose the safe route and didn't take a risk for an unnecessary plus.

That's how I looked at it anyway. Maybe I'm just a wuss but my boosted 7A is just fine with the stock metal HG

This post has been edited by hurley97: Jan 1, 2009 - 11:01 AM