Had a machine shop mill a head, he said needed .0009 to clean it up. It had a 3 notch HG. That sounded like alot .0009. Anyone had experience with like?
Do you mean .009"?
.0009 is 9/10000 and an incredibly small amount. I had my head taken down around .010" and the guy screwed up so I had it skimmed another ~.008" for a total of ~.018" with no ill effect.
Either way, it has no bearing on the thickness of your head gasket.
Chris
You're right. I was thinking 9 thousandths but typed other. I noticed the IDI eng.s the valves are recessed below the deck more so than the TDIs. Have to take the valves out to mill head.
And just to be clear for folks who may come here one day using Search... since it seems to come up a fair amount:
Either way, it has no bearing on the thickness of your head gasket.
Any one know how much a head can be skimmed, or more exactly is there a point where the reduction of the valve recess means that the valve head actually catches up with the 'slowly' moving piston?
If this can happen, then the only solution would be a thicker gasket...
Or re-recessing the valves...
I don't think you can put a # on it, the valves recess themselves over time.
I guarantee they will be out of spec long before impact happens.
Any one know how much a head can be skimmed, or more exactly is there a point where the reduction of the valve recess means that the valve head actually catches up with the 'slowly' moving piston?
If this can happen, then the only solution would be a thicker gasket...
Or re-recessing the valves...
There is a tolerance, but the number escapes me.
Burn Your Money hit on the subject in a recent thread in the General section where he re-did his head. The tolerance is listed there.
But, the tolerance has more to do with valve stem length conflict on the butt end, rather than anything on the chamber end. After reaching the tolerance quotient - you have to grind the butts on the stems equally - the same amount you decked beyond low end of quotient.
Refacing the valve seats to proper face width would probably go in hand with those parameters. Since the seat face width has a tolerance also.
I've never been in this situation, have no first hand experience, and hope not too. Just throwing it out there to you guys.
