55oval

Hello,

After installing fresh LS7 lifters in my LS6, I am getting what sounds like bad lifter knock from only 1 lifter. After startup and some driving w/ knock, I narrowed the noise down to the #1 cylinder (stethoscope). I tore the rockers out, nothing looks amiss, PRs look straight, rockers healthy.
**I measured preload w/ Dial indicator, and I have strange measurements from the #1 intake lifter. Please help me understand what this means and if I can tear back into the motor to replace that in hopes to solve the problem.

Details:
Stock LS6, 60k miles. Ran just fine before these following mods all installed fresh just recently.
Boost Cam. Comp.
.614 .610 227 223 LSA 115
LS7 Lifters from Texas Speed
Comp Chromoly PRs 7.400
Dual springs etc.
Stock rocker assembly
LS9 Head Gaskets
Procomp Head Studs
Melling oil pump

I measured preload OVER AND OVER again with Dial indicator on most valves (because of difficulty mounting Dial indicator), saw consistent preload on all but the #1 intake.
I know the preload's a little high. I plan to go 7.375 PRs

#1: I-.75 E-1.05
#3: I-1.05 E-1.05
#5: I-na E-1.05
#7: I-1.05 E-na

Could this be a bad lifter out of the box?

Additional details:
#1 Intake rocker bolt did have gummier threads than the rest. I torqued to 24, checked Preload, no change, tried 26, checked preload. No change.
Idle Oil PSI- 40
w/ gentle revs, Oil PSI sluggishly climbs to 60-70
w/ harder revs, Oil PSI responds a little quicker to 70+
Noise definitely quiets with more Oil PSI
Noise is inconsistent. It has nearly disappeared a couple of times, almost as something has settled down, but will reappear, even if just idling.
Yes, torqued to 22ft/lb, let lifters settle all the way.
Yes, dial indicator in line w/ PR
Yes, untorqued and D.I. would return to 0 (to double check that I didn't bump the D.I.)
I tried, but could not compress any of the lifters AT ALL by hand using a PR.

Any help is appreciated.
Thanks All!

Pic for fun. Not actually showing a measurement.

gagliano7

Can you push the plunger in on that lifter? If you can't move the plunger then it could be collapsed. You could try spraying into the lifter to try and loosen it up.

Serioussn95

iTrader: (1)

You say dual springs but what brand? height? spring rate? im going through the EXACT same issue right now. Im now realizing that my PRC .650s have WAY too much open pressure for the use with LS7 lifters. Ill be switching to Morels once I get the motor pulled.