Ls7 lifter preload

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Apr 29, 2011 | 11:06 PM

robss96dcm

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Ls7 lifter preload

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

Apr 29, 2011 | 11:08 PM

wrd1972

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I play it safe and go 3/4 PZL, but thats just me. If I were racing, I would do 1/4 turn PZL.

Apr 29, 2011 | 11:17 PM

jaycenk

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I did a tad over 1/2. about 2/3rds

Apr 29, 2011 | 11:28 PM

gregrob

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Full turn is factory spec, and LS7 lifters are factory replacement. Soooo....

Apr 30, 2011 | 05:03 PM

SoxXpupPeT

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Quote:

Originally Posted by gregrob

Full turn is factory spec, and LS7 lifters are factory replacement. Soooo....

I had tryed that in my car. As im slowly doing them with the engine running it started to run like crap!

I have mine set at 1/4 turn. I might fool around and see how they respond at 1/2 turn

Apr 30, 2011 | 05:31 PM

z28_theantirice

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When I initially did my motor I did either 1/2 of 3/4 cant remember, ended up going with 1/4 and the motor felt a lot smoother with the 1/4 turn.

Apr 30, 2011 | 06:16 PM

gregrob

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Maybe they require less. It would be interesting to know what GM calls for on the LS7.

Are you guys using 1/4 turn sure your pushrod length is correct?

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Apr 30, 2011 | 06:18 PM

litch2004

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rrob, mine were measured three times by three different people and used a micrometer to measure test rod.

Apr 30, 2011 | 06:23 PM

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SoxXpupPeT

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Quote:

Originally Posted by litch2004

rrob, mine were measured three times by three different people and used a micrometer to measure test rod.

same here. but do remember. not all LS7 lifters are the same. There have been alot of reports with people having bad batches iirc

Apr 30, 2011 | 06:27 PM

#11

litch2004

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I remember. Mine are about a 2 years old. I have only put 200 miles on them. It was my rockers that were loud. Went back redid all of them and marked a line on the oily lock to determine movement. All is good.

May 1, 2011 | 08:34 PM

#12

robss96dcm

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Quote:

Originally Posted by gregrob

Maybe they require less. It would be interesting to know what GM calls for on the LS7.

Are you guys using 1/4 turn sure your pushrod length is correct?

My understanding is .060 on stock ls7 engines, in a lt1 that would be about 1.5 turns past zero lash!

May 1, 2011 | 08:54 PM

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speed_demon24

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Quote:

Originally Posted by robss96dcm

My understanding is .060 on stock ls7 engines, in a lt1 that would be about 1.5 turns past zero lash!

It would be about half that.

May 2, 2011 | 05:12 AM

#14

RamAir95TA

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I've always done 1/4 TPZL.

May 2, 2011 | 08:00 AM

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jasonz28camaro

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Yep, they call for 1/4

May 2, 2011 | 08:08 AM

#16

wrd1972

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Quote:

Originally Posted by jasonz28camaro

Yep, they call for 1/4

Based off of what reference?

May 2, 2011 | 09:44 AM

#17

the_merv

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From: The Beach...

LS7 Lifter perload is .080 ideal, can range from .060-.100, always go with the larger one past .080 when selecting proper pushrod size.

There is a difference in the LS7 Lifter vs. the others..different Pushrod lengths get specified if you use them , I beleive the number most are using is .025", but it would be best to measure.