r572cobra

anybody know the lifter preload,on these.

Sales2@Texas-speed

iTrader: (5)

Are you sure it's a 975? Maybe an 875 instead??

r572cobra

your right i meant 875.thanks

JPH

iTrader: (2)

run .020-.040 hot.

r572cobra

I checked the pushrod length an got,almost 1.5 turns.then checked with a dial indicator,and got about .070 ths.this cold on the engine stand.buddy of mine built a ls3,with far heads,same lifters,060.preload,and 7.4 pushrods.6k on motor with no problems.what do you guys think?

r572cobra

nobody else have any imput on this,i really dont want to spend the money,on another set of lifters if I can make these work.

Sales2@Texas-speed

iTrader: (5)

If you've got the 875's, you need an adjustable rocker to setup preload properly! They require .002-.004" of preload, otherwise you'll have problems (noise just being one of them).

r572cobra

I understand what you are saying.read on here,some people are using stock rockers,with no problems and would like to here from them,thank you.

Sales2@Texas-speed

iTrader: (5)

Yes, some get away with a stock rocker on the 875 lifter combos....but you have to get VERY close on the preload to start, and then you shin them to get the preload where you want it. The issue with that is you start messing up your geometry just to get the right preload, which is no better than having the wrong preload to start with!

If you search on here, you'll find a few people who have been successful with the stock rockers using this method, but 99.5% of them will complain of loud valvetrain noises and/or instability, and then having switched to an adjustable rocker.

Darkman

iTrader: (2)

https://ls1tech.com/forums/generatio...oad-setup.html
https://ls1tech.com/forums/lt1-lt4-m...djustment.html
https://ls1tech.com/forums/generatio...r-lifters.html
https://ls1tech.com/forums/generatio...r-lifters.html
https://ls1tech.com/forums/generatio...-collapse.html

r572cobra

Darkman,I noticed most of those post,were in 04/05 years.did comp fix the problem?I checked with a pushrod checker and 7.300 will give me the right preload cold.I'm running a big comp cam 474-11,251/267.624 lift.the motor is not in the car yet.pushrods are cheaper than lifters.

Darkman

iTrader: (2)

The main issue here is not a lifter manufacturing problem, it is rather a deliberate design feature - these are close-tolerance high performance lifters.

The pre-load range is from 0.002-0.004 inch. (One poster above misstated it.) You cannot establish a pre-load level within plus/minus two thousandths of inch using a pushrod checker nor can you measure it based on the number of turns on the OEM rocker.

The simple fact is, if you do not have an adjustable valvetrain you cannot set and maintain these lifters to the manufacturer's specifications. Thus you cannot expect them to be reliable.

SweetS10V8

iTrader: (4)

Yup,

You can use 875s if you have an adjustable valvetrain. If you have a non adjustable vavletrain you have to use the 850s. I have the 850s in mine.

Sales2@Texas-speed

iTrader: (5)

Precisely. Well stated.

r572cobra

will the ls7 lifters be okay with that size cam,i cant afford the rockers right now.

Darkman

iTrader: (2)

LS7 lifters will work with that cam providing, of course, that you don't plan on operating at some unusually high rpm level.