Question on lifter preload and lifter plunger.
Please explain to me what you don't understand about the difference between a bolt and a nut?
Staging Lane
Joined: Mar 2011
Posts: 80
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From: Kentucky
Pure mechanical genius on display, from the guy who tried to fix oil burning with a tune:
https://ls1tech.com/forums/generatio...e-exhaust.html
https://ls1tech.com/forums/generatio...e-exhaust.html
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Verdad Gallardo
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From: Turnin' Wrenches Infractions: 005
That was Shane at Thunder Racing's way to do it. And yes it works.
And to the damn fool who is saying .10 is acceptable pushrod preload, shoot yourself because that's ridiculous.
And to the damn fool who is saying .10 is acceptable pushrod preload, shoot yourself because that's ridiculous.
You get the lifter on the base circle of the cam(so valve is closed) you start by putting the pushrod in at stock length. Get to zero lash explained above. Then for Every turn after zero lash is .047 preload. You want .70 to .090. If you can only go a half turn lets say before it torques down you need a longer pr. So you adjusrt it longer and see where your at
this measurement is incorrect, and your desired preload is incorrect with an aftermarket cam
first off...aftermarket cams want to see .020~.060 preload...and yes, it does make a difference, the extra ramp rate will want less preload to make it quieter, and it will make slightly more power with less preload, and have more valve control.
secondly...the math for preload needs to account for rocker ratio as well
so ...Thread pitch of 1.25 = .0492126
but that assumes 1:1 rocker....
with a 1.7:1 rocker (stock LS1), it becomes 0.0492126 + (0.0492126/1.7) = .078161 per one turn of rocker bolts......
if you dont believe me, Use a Dial indicator, and you will see one turn is .078
On The Tree
Joined: Nov 2012
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I'm at .076" preload with my COMP XER 281 with 7.4" pushrods. COMP told me that was on the high side, but it shouldn't affect performance. Their "ideal" spec for my cam is .060" preload. I asked if I should change to a shorter pushrod and they told me not to worry about it.
Frank
Frank
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This is why I ask questions and make. Threads. You can have so many people thinking one thing, then some one comes a long with new info and makes everything else incorrect.
Little to late, all ready installed 7.430 pr because with the 7.4 i was getting about one full turn. So I guess im at like .100 preload, awesome.
Little to late, all ready installed 7.430 pr because with the 7.4 i was getting about one full turn. So I guess im at like .100 preload, awesome.
There is a ton of misinformation in this thread, and it's on both ends of the spectrum. If you aren't going to buy a $20 checker, please just follow Shane's instructions that were posted above. No less than 1 turn of the bolt should be considered acceptable with gm lifters. If possible I like 1 1/4 to 1 1/2, it will be quiet and stable. A little more is acceptable and is generally not a problem.
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800-456-0211 / PM / Facebook
WHIPPLE Superchargers, Procharger, Magnuson, Powerbond Sale, HPTuners packages!, Trickflow, AFR, PRC, CHE Trunion upgrade, $100 7.400" pushrod set, Custom Cam of your choice
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the pr checker isnt the question now,its how much preload is in one full turn with 1.7 ratio rockers? Any one have their valve covers off and a dial indicator?