Curiosity question.
When type 4 heads are to be fly-cut for increased compression, where/what plane does the machinist set up on. Videos seem to show the setup is the head being clamped on the valve cover surface to the mill table.....
So is that surface suppose to be parallel to the chamber sealing surface??
If so what is acceptable variance across the sealing circle to the valve cover surface.
We have measured our new set of 2L head castings and there is up to a .002" variance from on side of the sealing surface to the other with respect to the valve cover surface. So in this case the sealing surface is not parallel (in the same plane) to the valve cover surface? But does is matter as long as the sealing surface itself is flat all the way around to the to the cylinder top and both chambers on each head are in the same plane?
Do these heads need touched up?
What am I missing here??
Thanks
jjs3rd914