Anyone have any experience replacing head gaskets when the block has been O-ringed around the cylinders? Do the o-rings need to be replaced/machined? Can I use aluminum cylinder heads without having a receiver groove cut into them?
What's a good thin head gasket out there? I'm looking to raise my compression.
thanks, and

 

How far does the o ring stick up from the deck? Normally you can just replace the gasket.

 

What exactly are you working on ? Which engine ? What type of gasket was on it ? O-rings are typically used with a copper head gasket and most of the time have a receiver groove cut in the head to match.

I know some guys that use O-rings with other than copper gaskets but they are in very specialized racing applications. Unless you have a very thick gasket now changing to a thinner one gives a very insignificant compression gain. In my opinion not worth it when you weigh in the fact that the thinner gaskets do not seal as well over the long term.

 

Thanks for the reply, I haven't taken the heads off yet, I was just wondering what I'm in for if i do take the heads off.

 

its a 68 olds 455 from a Toro, I built the motor about 13 years ago, and when I did i went with my machinists advice and took the bare minimum off the deck and heads, and went with the l2323 18cc pistons, he put the o-rings on the deck and nothing on the heads, the gaskets I put on it were thick, white corteco gaskets he sold ($28 each), if their what I remember they were about 4.400 bore .060 thick, and if I'm right I can raise my compression about 1/2 a point switching to a .025 4.155 gasket.

 

I just looked in the Edelbrock catalog. Their gaskets used to be Corteco, not sure if they still are. Their Olds gasket is 4.230 bore and .038 compressed. If that is what yours is you really are not going to gain much.

 

I just measured them with my caliper, for what sticks out between the block and the heads its .060, and I remember them being quite a bit bigger then the bore... my receipt says corteco hg-olds. I know they were white plastic like gaskets, no ribs or anything, cheap $14 each, no packaging, coat them with spray copper sealant.