Roller lifter preload

[tdda100]

Hey I'm new to the forum thing . I'm working on a 318 pre magnum roller engine. Have lunati cam ultra pro magnum rockers and I'm measuring for new push rods. I adjusted the rocker for 1 thread just showing by the cup and adjusted the check pushrod for 0 clearance now I need the preload number. Is the rocker supposed to be 1 thread or less. That's what I've seen for factory rockers And I have the mopar performance engine manual and it says the tappet dry lash is .06 to .210 inches for the magnum engines I think they use the same lifters. Just sounds like a lot to me. I want to have to the right numbers before I order new push rods.
It's all going into a 71 charger I bought last summer. Got the 518 installed already. Thanks

[John_Kunkel]

Welcome to the board.

You have to understand the difference between valve lash and dry-lash, both are different than preload.

Valve lash is the clearance between the rocker arm and the valve stem tip with solid lifters, dry-lash is for hydraulic lifters and is also the clearance between the rocker arm and the valve stem tip but is measured with the lifter collapsed. (thus the wide range)

Preload is the amount the adjuster is turned in from the zero lash position, one-half to one turn is common depending on who you listen to. IOW, turn the adjuster for zero lash and then turn it an additional amount to preload the lifter.

[tdda100]

Thank you very much. Learning something new everyday is a good thing. I'll add .03-.05 and pick a rod that's close.