LS1TECH - Camaro and Firebird Forum Discussion

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-   -   Don't Hate Me another valve lash Question (https://ls1tech.com/forums/generation-iii-internal-engine/1799586-dont-hate-me-another-valve-lash-question.html)

shoeboxvette Aug 23, 2015 07:29 PM

Don't Hate Me another valve lash Question
 
Ok, Changed heads, Cam, lifters, Got the Comp pushrod checker. Found Zero lash on several valve locations, reset checker to that length pushrod tightened rocker arm down all came down to 1 1/4 turns +or - I came up with 7.350 pushrod with .100 preload Just checking before I order pushrods
Thanks for looking

Exidous Aug 24, 2015 06:00 AM

What lifters? .100" is a lot of preload.

redbird555 Aug 24, 2015 06:27 AM

Ya I'm a little confused here lash is what's used to determine the play between the rocker and the valve. Preload is how much the pushrod is pushing on the lifter, two very different things.

You want to find zero lash then check the length of the checker like you have done and then add whatever preload you want. It's a non adjustable hydraulic roller, there is no lash. With that said if you are using stock ls7 lifters I would shoot for .07 preload. You can run more and you can run less but that's a good medium. With that said 7.35 seems short unless you have head work or something else done

shoeboxvette Aug 24, 2015 12:36 PM

Stock rockers with trunion upgrade, GM hot cam, 243 heads, ls7 lifters, .051 head gasket. 6.800+ 9 X .050 .450 + .100 Preload 7.350 with this from zero lash to tight it took 1 1/4 turns on the trunion bolt.

The stock 7.400 pushrods were almost 2 complete turns zero lash to tight

Exidous Aug 24, 2015 12:58 PM

You are using a 7.350" PR yes? If so 1.25 turns after zero lash is fine for LS7 lifters.

The difference in preload between a 7.350 and 7.400 PR should be just about 1 turn.

06blackGTO Aug 24, 2015 01:36 PM

Yeah. If your sure your on base circle on the rocker your checking. Eoic. I snugged up the rocker bolt till the pr could spin but no up and down play. Then I tightened up the rocker till 22ft. Lbs. And had 1.25 turns. That is what you want. 1.25 to 1.50 turns to reach 22ft. Lbs. After valve lash.
Someone correct me if I'm wrong, but thats how I did mine shoebox.

Exidous Aug 25, 2015 06:39 AM

Sounds good.

shoeboxvette Aug 25, 2015 01:31 PM

Got it, Thanks for help, push rods on the way.


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