Inliners International Forums General Discussion Engines 235 cylinder head resurface

I know this has been covered beforre but I can't seem to find it using the search funciton. What is the max safe limit a 235 head (848 casting) can be resurfaced?
Thanks BC

Are just resurfacing to give a clean surface or are you trying to correct warp or a defect??? I have taken them down easily .060 and never had a problem.

When you milled them(I assume for performance gain, at .060"), what did you do to correct pushrod length issues? Will the hydraulic lifter take that up?

depends on the geometry.... +050-100 valves and yes, change push rods accordingly..... they are the last to go in anyway... Buick I8 push rods are easy to change, tubular and you can adjust the rockers too. .060 isn't much but it can be a mile if the geometry is off!!!

I just remembered that there is an adjustment screw on the rockers of my 261 at the head of the valve. Wouldn't readjusting the valve clearance solve any clearance issue? Or is that where the milling comes into play-the adjuster gets moved further off the centerline or centre of the valve tip after the head is cut?

It will solve most clearance issues but it depends on the reason for the cut.... take off less than .020 you get a nice surface for the gasket but not much changes. Final adjustment come with setting lash later. The more you take off the more you need to adjust. Geometry, fulcrum, duration, lift etc. Trunions are the usual location for adjustments. Never seen one one the front of the rocker arm. But again, I am new to stovebolts and inliners. Gimme a fat V8 sbc or bbc and we can talk real HP and torque changes in the valve train!!!!

Cool, again, I was thinking .060 to bump up the compression a little. You know, from 8:1 to, like, 8.3:1. Ha, ha, ha.

Milling the head has no effect on rocker geometry, as long as you still have an adjustment.
However, any more than a light pass eats the intake valve seat, and when this is re-cut deeper the valve gets taller - this will require a correction.
The easiest is to shorten the intake valves by the same amount as the mill cut, but you may not have enough room before the collar strikes the rocker arm.
Shimming the rocker stands (same amount as the mill cut) has been suggested as a correction, but unfortunately it causes the reverse error on the exhaust valve geometry. This needs either the exhaust valves sunk (not a good idea), taller exhaust valves, or lash caps on the exhausts.

Are you sure the intake valve will not strike the piston?

The exact math isn't so easy, but the effect is very small and safely ignored.
The valve height correction is the cosine of the valve axis angle, so the intake height adjustment is 100.2% of the mill cut, the exhaust is 104%.