SmartOJ

iTrader: (44)

I need you alls expert advice...my new engine is calling for 7.323 pushrods at .080 preload with ls7 lifters.so ill just say 7.325. ....i already have 7.35 pushrods which will push my preload to .1006xx.............i've seen in a few thrreads about the .100 range, but is that really a safe preload for ls7 lifters? or will that be pushing it too close to the max?

vettenuts

iTrader: (4)

I ran my LS1 OEM lifters deeper than that for a while and didn't any issues.

willyfastz

Well the closer the preload is to 0 the better the power will be. A lot of the stuff we do I run between .040 to .060. Depending on the street use we may put them at .020.

I personally wouldn't want to run them at .100. The .040 to .060 seems to be a good compromise with all out power and a quite valve train.

Would .100 be safe? Yeah most likely, I've seen some of the factory stuff higher than that.

Darkman

iTrader: (2)

Why do you say that?

willyfastz

Because that's the truth. I've never understood why so many in the LS world think they have to run such tight preload.

Headed to clean some right-a-ways for the deer stands. We can talk more about this later if y'all wont.

Darkman

iTrader: (2)

I have encountered others taking the opposite position, i.e. that the highest possible preload maximizes power allegedly because it results in maximizing both duration and lift. I have not however, encountered any empirical evidence supporting that position or yours.

Later.

SmartOJ

iTrader: (44)

I dont want to pull the heads again because of a busted lifter......

Darkman

iTrader: (2)

The LS7 lifter has a plunger depth of 0.166 inches.

https://ls1tech.com/forums/16198881-post4.html

willyfastz

Yeah I read all the BS about the tight lifter preloads as well. I guess time on the dyno would answer that. It's kinda like the old SBC engines. When adjusting the lash on them most find 0 lash and then give the nut a half turn for street use. For mostly track use some leave it at 0 or give it just a 1/4 turn for best power.