I seem to be a little confused here, most people using the ls7 lifters in lsx applications are shooting for about .080 preload. When installed in lt1 applications there going about a 1/4 turn past zero which is about .010 preload if my math is correct.

Why so little in the lt1's or so much in lsx's?

 

Good question, I did mine on both cars with 1/2 turn past zero, and they are kinda noisey. I'm going to 3/4 to see how it works. I've been told by a few to do 1/4 past zero. Problem is people's zero is slightly different from person to person and depending on how you do it.

However the LSX guys to tighten them up more than we do... With a more shallow pushrod cup I wonder if they are able/designed for more preload.

1/2 a turn on a 7/16 is what? .040 @ the lifter?

-Dustin-

 

I just installed mine in December on my LT1, used 2/3 turn and no noise.

 

I run mine at 1 full turn after o, never had a problem .

 

I've never chased horsepower in the minuscule amounts you'll find with pre-load adjustments, we use solid lifters in real race motors...but the reasoning behind running a hydraulic lifter at very light pre-loads or even lash in the .004" range is to eliminate slight power loss from lifter pump up which can hold the valves open when it overwhelms the spring pressure.

Depending upon who you ask they'll say run .080", or .010" or very specifically .020"-.040" on the LSx motors, the reality is that most of the lifters will act very similarly and unless you have a short travel lifter just setting them at 2/3 turn is the best for a street motor.

 

This grossly over benchraced because one particular hack was selling junk valvetrains and blaming preload for all the problems he was causing.

By pushing for near zero preload he could mask some of the valve bounce his gross incompetence was causing. This community lacks basic reasoning skills though and many still worship him despite banning on all the major LTx forums. No matter how mediocre his junk is it is praised.

 

What are you running yours at? I know you over investigate everything similar to how I do, so I'm wondering what conclusion you've come to.

-Dustin-

 

I have come to the conclusion that this is grossly over benchraced.

I did 1/2turn + snugging the polylock and setscrew together so say 5/8 total when the GMPP guideplates wore out 8-10k later I tried near zero which did nothing but make more noise so I went back to around 1/2 turn, and people I trust have gone as far a 1 full turn. If your valvetrain is under control it doesn't really matter.

If you find less preload makes more power it is probably reducing valve bounce from a worn out set of springs or just a badly matched valvetrain.
REALLY well documented that some folks have valve bounce issues when one guy tried set after set of springs only increasing pressure at lift and the problem didn't go away till he gave it more seat pressure and then got a freebie cam to replace the hugely popular POS he had.