<TECH ONLY> Lifter Preload
01-15-2010, 07:49 PM
#42
I don't get it. I am running 341s (stock SS heads, I think thats the number), no milling, LS7s, and an .041" head gasket and I had to get 7.300 PRs to get .050 preload. No lifter noise, at least none that I can detect over the sewing machine patriot golds.
09-22-2010, 11:37 AM
#43
Here's a link that Steve Bryant hooked us up with, thanks Steve, good info:
https://ls1tech.com/forums/generatio...r-preload.html
https://ls1tech.com/forums/generatio...r-preload.html
09-22-2010, 11:49 AM
#44
Here's some info from Comp Cams about installing their hydraulic lifters and setting preload. I found it good to know that they say not to "pre pump" the lifter, and also that pre-soaking the lifters in a bath of oil is a good idea but not mandatory 
http://www.compcams.com/Instructions.../COMP4-115.pdf
http://www.compcams.com/Instructions.../COMP4-115.pdf
12-04-2011, 04:04 PM
#45
Comp Adjustable Rockers
I've been looking for info on how many turns to adjust my adjustable rocker arms, most posts are about pushrod length. They are COMP Cams 1375-1 - COMP Cams Pro Magnum, with comp studs. They are 1.75 ratio.
I finally put a dial indicator on the pushrod end of the rocker, and measured 1-3/4 turns of the adjuster to be .105", +-.
I thought others might find this useful.
I finally put a dial indicator on the pushrod end of the rocker, and measured 1-3/4 turns of the adjuster to be .105", +-.
I thought others might find this useful.
01-05-2016, 07:53 PM
#46
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After reading all of this I'm slightly concerned when I get ready to install the valve train. So if I buy LS7 lifters and trays for a stock 02 5.3 with 7.4 hardened pushrods and stiffer springs to go with something like a HT1 truck cam I thought you just snug them up and then torque to 22 ft lbs. no I need to worry about preload? Should I just run new OEM lifters? Is there a real big advantage for the LS7 roller lifters if I'm running a low boost and around 6000 rpm limit? My concern is reliability.
01-07-2016, 07:07 PM
#48
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I've read a few threads and saw a couple videos and it looks pretty easy, just need the tool. A couple of people are saying I shouldn't be concerned since the only thing I will be milling heads or changing rockers or much from OEM. You think it's necessary to verify PR length and set a specific preload insread of just torquing to 22 ft lbs? Then again others say it's critical to verify length and set preload.
01-07-2016, 07:20 PM
#49
this is the method i used
Originally Posted by XtraCajunSS
FWIW, EVERY cam install I have done using the LS7 lifter with a cam with greater than .600" lift (read smaller base circle) AND stock heads w/GM MLS gaskets has taken 7.425" pushrods for ~.050"-.060" preload. We measure lifter preload on each and every cam install we do. I have never had a lifter failure nor do we end up with the dreaded "sewing machine" noise.
Its very simple, If you change ANY of the following:
valve sizes, valve job, head milling, thinner/thicker head gaskets, decked block, cam with an altered base circle, etc... YOU MUST CHECK FOR PROPER PUSHROD LENGTH.
I have helped countless numbers of individuals with this process over the phone, via email, and PM's. I've posted the process on at least 3 occasions.
Here it is again in a nutshell:
1. Using the EO/IC method, get the lifter to the base circle of the cam.
2. Using a known length pushrod (7.400" is a good start with stock rockers) run the rocker arm bolt down to zero lash. This is easily done with your fingers "wiggling" the rocker, the point at which the "slack" is just gone is zero lash.
3. Set your torque wrench to 22 lb./ft. Tighten the rocker to full torque and count the number of turns it takes to get there. 1 full turn wtih a stock 8mm X 1.25 bolt is ~.047" preload as measured at the pushrod/rocker interface.
4. I normally shoot for 1 1/4 to 1 3/4 turns with stock type lifters like Comp 850's, LS1, LS7 etc.
For an example, if you use a 7.400" pushrod and come up with 3/4 of a turn, you will need at least .025" longer pushrod to get into range. If you end up with 2 1/4 turns, you will need one .025" shorter...
I might not know everything but I will tell you that this method has worked for me year after year cam swap after cam swap. We average 3 cam swaps a week here so you can do the math.
If you are not familiar with the EO/IC method for determining valve events in a 4 stroke engine, its very simple:
For a given cylinder as the Exhaust valve is Opening, the intake lifter will be on the base circle of the cam and lash/preload should be checked for that intake valve.
For a given cylinder as the Intake valve is Closing, the exhaust lifter will be on the base circle of the cam and lash/preload should be checked for that exhaust valve.
THIS METHOD ALWAYS WORKS!!!
I hope this helps someone. I have explained it so many times I think I do it in my sleep!!!
Shane_______________________________
Originally Posted by XtraCajunSS
FWIW, EVERY cam install I have done using the LS7 lifter with a cam with greater than .600" lift (read smaller base circle) AND stock heads w/GM MLS gaskets has taken 7.425" pushrods for ~.050"-.060" preload. We measure lifter preload on each and every cam install we do. I have never had a lifter failure nor do we end up with the dreaded "sewing machine" noise.
Its very simple, If you change ANY of the following:
valve sizes, valve job, head milling, thinner/thicker head gaskets, decked block, cam with an altered base circle, etc... YOU MUST CHECK FOR PROPER PUSHROD LENGTH.
I have helped countless numbers of individuals with this process over the phone, via email, and PM's. I've posted the process on at least 3 occasions.
Here it is again in a nutshell:
1. Using the EO/IC method, get the lifter to the base circle of the cam.
2. Using a known length pushrod (7.400" is a good start with stock rockers) run the rocker arm bolt down to zero lash. This is easily done with your fingers "wiggling" the rocker, the point at which the "slack" is just gone is zero lash.
3. Set your torque wrench to 22 lb./ft. Tighten the rocker to full torque and count the number of turns it takes to get there. 1 full turn wtih a stock 8mm X 1.25 bolt is ~.047" preload as measured at the pushrod/rocker interface.
4. I normally shoot for 1 1/4 to 1 3/4 turns with stock type lifters like Comp 850's, LS1, LS7 etc.
For an example, if you use a 7.400" pushrod and come up with 3/4 of a turn, you will need at least .025" longer pushrod to get into range. If you end up with 2 1/4 turns, you will need one .025" shorter...
I might not know everything but I will tell you that this method has worked for me year after year cam swap after cam swap. We average 3 cam swaps a week here so you can do the math.
If you are not familiar with the EO/IC method for determining valve events in a 4 stroke engine, its very simple:
For a given cylinder as the Exhaust valve is Opening, the intake lifter will be on the base circle of the cam and lash/preload should be checked for that intake valve.
For a given cylinder as the Intake valve is Closing, the exhaust lifter will be on the base circle of the cam and lash/preload should be checked for that exhaust valve.
THIS METHOD ALWAYS WORKS!!!
I hope this helps someone. I have explained it so many times I think I do it in my sleep!!!
Shane_______________________________
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