Setting valve lash with new, non filled hydraulic roller lifters

Bakerlite said
That's OK, I didn't think that. I was just putting up some food for thought.
People seem to worry about pumping up the lifter, but when you remove the rocker gear, say to change valve springs, the lifters actually pull in more oil and effectively "pump up".. Then they bolt on the rockers and run the engine oblivious to that fact.
If you preload a lifter at say 0.020, how much valve lift would that be if the lifter pumped up VS how much piston to valve clearance you should have?
Also when you prime the lifter, you don't need to prime it till it's solid..If you have had them apart, then you have seen how much oil they hold.
Also if you look in a Chrysler manual they warn you not to rev the engine above fast idle until the lifters bleed up. But that becomes an issue when you need to run in a cam...

Ah THAT'S why my Magnum roller lifters pumped up... Must have been oil left in the lifter galleries, when I unbolted the rockers at the junkyard they pulled in more oil.

I strongly lean towards doing a thorough prime on a fresh build to get the lifters pumped up to the proper height instead of priming the lifters individually out of the engine. Run the oil pump and slowly rotate the crank 2 full rotations, if your lifters aren't filled by then there's probably something wrong. In my mind that's the least-risky way to get the engine primed and ready for breaking in a flat-tappet cam.

Also it's a very good idea to take apart and clean out new hydraulic lifters, sometimes they have residue or whatever in them that can clog the tiny oil passages to the cylinder and plunger.