I only have about 150 miles on the car since rebuild and I’ve had to adjust the lash on the same valve at  5 or 6 times now. All of the others valves seem fine fine, but the lash on a valve on #6 constantly needs readjusting. I understand that the engine is still break-in stage, but I’m beginning to think something is wrong.

I initially set the lash up to be .019 on all valves, but am now going as tight as .018 on the problem valve and it still loosens up after an afternoon's drive.The lash on that same valve has grown to .024+ after only 20-30 miles of driving. Does anyone have hunches as to what’s going on? Do I have some kind of unusual wear problem with that rod, lifter and/or cam lobe? This does not seem normal to me. Or Is this normal while breaking in the engine and how often should I expect to redo the valve lash?

New parts:

cam

pushrods

valves

springs and retainers

rocker-arm shafts

Freshly Machined:

rocker arms

lifters – good old original ones

heads  - including hardened valve guides for unleaded gas.

I broke in the engine right after first start up by running it for approx. 20 min at 2500 RPM.