Hydraulic lifter preload?
 

I've noticed that couple of my rocker arms are wearing down where they contact with the valves. I put new ones in but the valve stem is worn down a bit causing lash (these are completely unadjustable DOHC).
I can make shims to go under the lifter (lash adjuster). And I want to know about what preload I should run. So far I put in a .020 shim and there was still lash When I put in a washer .063 there was no lash. So I think somewhere in between will be right.
I'm going to have to find out why this is happening. But in the meantime I have a race in Concord to get to.
Thanks