4 replies to this topic

[babsbrown]

Good evening guys,

I thought I had settled on using a 12g202 cylinder head for my build but having read so many good reviews about the 12g295 I'm thinking of using that instead.

Only problem is, as we all know they suffer from valve recession. I want to get it sorted eventually and get unleaded seats and bigger rimflow of GS valves fitted. But at the minute out of my budget.

Given the above is the head actually useable with the valves in the current state? They bounce up when dropped down into the seat and they seat with water in the chamber. The valve seats are actually pretty decent

 And cleaned up well with a lapping in

Cheers, Babs

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Edited by babsbrown, 19 December 2024 - 09:28 PM.

[dotmatrix]

not the most conclusive answer ever: but it doesn't look right

[slidehammer]

I would say if you are sure you are getting a good valve seal on all chambers, it is usable as a standard road head, but would never work as a performance item with that amount of valve recession. The inlets are recessed too, which would indicate to me that the valve seats have been recut at some point.

[Shooter63]

Have you cc'd the chambers yet? With the valves in like that you have gained a few cc's and if I remember right you are struggling to get the compression up to a decent level. Apart from that the head looks usable if not ideal.

Shooter

[babsbrown]

Cheers gents, @shooter I did CC the head and it came back around 28cc average each chamber. That would still imply I need a good 80 thou skim to give me decent CR.

But after sleeping on it, I think I'm just going to shove it on the shelf for another build and get it sorted in due course.

I'll get a 12g202 skimmed for now. I wish I'd have honestly bought flat top pistons now ,but we live and learn.


Cheers again