shoebox

The 1 turn has been the norm from GM on hydraulic lifters for like forever. The actual LT1 spec is 1 turn + or - 1/4 from zero lash.

hairbear21

Awesome, thanks a lot guys!

truedualws6

Dan, as also stated by shoebox, and to quote my 1997 factory service manual "When all the free
play is gone, tighten the valve rocker arm nut 1 additional turn (360 degrees)". If you have a
service manual it's on page 6A-265.

wrd1972

Good dicussion.
Is there any truth that for higher performance motors using OEM lifters that 1/8 - 1/4 turn PZL is more desirable than the GM spec of 1 turn PZL?

stereomandan

Wierd. I know there was a very good reason that I used 3/8 turn with my 7/16" studs, at the time. I did with the engine not running, and it has been fantastic. Very quiet, no ticking, no performance issues that I can find...

I thought that I had calculated what the max capable preload is (basically when the lifter becomes solid) and shot for half way to that point. That way I would have equal travel for the roller in the lifter in both directions.

Maybe I calculated it wrong? What is the distance from zero preload to full solid on a stock GM roller lifter?

Dan

wrd1972

Anyone want to speak to this

shoebox

The old adage is "looser is faster". Looser=less preload.

stereomandan

I'm going to stick with 3/8 turn on stock lifters, with 7/16" studs. Even if I swap to a new cam. My valvetrain sounds great, and I don't get any false knock (I datalog my car a lot).

Dan