I plan on adjusting these again tomorrow afternoon but figured I'd ask for some opinions. Brand new LS7 lifters, (and brand new PAC 1218 springs) all adjusted to 1/4 turn past zero lash while the motor was running. I get a tick now which gets louder as the motor heats up.. Checked all the spark plugs and for exhaust leaks, and am pretty sure its valvetrain noise. Is it possible that I don't have the ls7 lifters preloaded enough? I've read some other posts stating 1/2 turn, and even the GM stated 1 full turn..

Any thoughts are appreciated!

Background: had to change the Comp Cam beehive springs, had 3 broken in under 1500 miles on newly rebuilt motor. Since I was swapping out the springs I figured I'd also replace the Comp R lifters for ease of mind. Bought the LS7 lifters, soaked them in oil for an hour and then installed.

 

All the LSX people set their cars up for ~.060-.070 preload, but according to some engine builders on here you get the most power as close to 0 lash as you can get, but the valvetrain will also be noiser that way.

 

Interesting... Anyone else with any input? Have to spend the day helping my Brother put a roof on his 2 room addition, so I cant reset the lash until tonight. I'll post back my findings shortly afterwards.

 

I'm not sure how they compare to the stock LT1 lifters, but optimal for the LT1 lifter is 1/2 turn if you have 3/8" rocker studs, or 3/8 turn if you have 7/16" studs. (due to the difference in thread pitch)

I forgot the thread pitch for the 3/8 and 7/16" rocker studs, so I can't calculate how far you need to go to get to 0.060" preload on the LSx lifters.

Dan

 

With 7/16 studs every 1/4 turn was about .020 preload. I measured this with a dial indicator since you can't just use thread pitch since the pushrod sits back and goes down faster than the thread pitch, I don't know what the ratio is though.