I'm getting a bit weary of using a copper gasket and I'm not sure that the costs are going to outweigh the impracticalities of using one.

Has anyone ever opened up the chambers on a GX head to increase chamber cc in an attempt to reduce compression ratio? Approximately how many additional cc's can I recuperate, assuming that my chambers are currently just over 19cc's?

I don't think I'll ever go back to methanol or ethanol blend so I figured I won't ever need that compression ratio so I might just spend the money that I would spend on the copper gasket to modify the combustion chambers? Does anyone else see the logic in this?

Copper gaskets are impractical? Just the cost. If you use the right sealer, they are super reliable.

But a thicker gasket is not the best way. Better is to fit pistson with a larger dish. A14 pistons come factory with about 4 different dish types.

I have heard of people sinking the valve seats deaper, and then you could regring the radius in the chamber witch should be equivilent to the lift. the datsun chambers arent to bad for a 2 valve non crossflow head but they can be improved.

Budget is an issue here and rebuilding the engine to install dished pistons is out of the question. For now anyhow. I'd have to replace bearings and rings while I were at it.

Well they are impractical compared to a standard gasket. I also haven't planed my engine block so I am somewhat expecting to encounter sealing issues. I would expect to pay $200 for a copper gasket and then the pricey sealant to seal it.

why not just bung an 89 on there and not molest the GX head..

Well that's the issue the head has been molested big-time. It has had ALOT milled off it.

Replacing head means more costs on purchasing, rebuilding and porting a H89. All my manifolds bar the bpro one you sold me are port matched, and the one you sold me is to suit GX ports so I'd have to port the head anyway to suit the H89.

Basically looking for the most practical and cost effective solution. And opening those chambers so they aren't so kidney-bean-shaped may be the way to go.

Ring BigE...
he'll clue u in bro...

Yeah I don't like bumming info off engine professionals unless I'm going to spend money with them. And with the postage costs etcetera, I'm not sure that I can afford to work with BigE.

I don't mind picking info from you lot! Keep it coming.

Connor wouldn't that then mean I'd have to modify my valves as they sit higher and closer to the rocker arm. Or I'd have to get a custom retainer made up or get slightly taller springs.

Chambers

you could mill some out like this..