12g202 1098 head mesaurements

[Alex'n'Ane]

Does anyone know how much you can or should skim off a standard 1098 12g202 head? And the measurements from face of head to where?

[katy]

Saved from an earlier post:

"Measure the thickness of the head - from top to bottom - between the machined faces. They were all 2.750" when new."

I don' have a clue as to how much can or should be be skimmed off the head. I'm sure there are others on here who can supply that info.

[bmcecosse]

Looks like a quote from a post of mine..... How much to skim off depends what you want from the head, and what engine you intend to run it on! It's not a great head - so not worth spending much time or money on it -although with say 60 thou off it is a worthwhile 'stage 2' upgrade for a 948 engine. You can often pick up a 12G940 head for not much money - and this is a MUCH better head - and needs no skimming. I have taken 120 thou off a 202 head - but the surface became noticeably 'flexible'.... I would advise no more than 80 thou if you want reliability.

[Alex'n'Ane]

Thanks, I do have a 12g940 also, but i think the exhaust valves need sinking, which is a specialist job is it not? However I also have a 12g202 head which just needs a skim, which I can have done for free.

[bmcecosse]

Measure the clearance of the exhaust valve heads from the head face - you need 320 thou (assuming standard lift cam etc). Sinking the valves is a 5 minute job with a 45 degree countersink in a pillar drill!