Easiest way to check lifter preload?
Thread Starter
TECH Enthusiast
iTrader: (9)
Joined: Dec 2004
Posts: 584
Likes: 0
From: Charleston, SC
Easiest way to check lifter preload? What's the easiest way to check lifter preload? I'm not sure my pushrods are the correct length so i wanna check my preload and make sure i get the right length pushrod in my TA.
Either with a dial indicator, or if you can tighten the rocker until you just take out the lash, then tighten it until the slop it out of the rocker bolt (don't torque) so that you are compressing the lifter. Multiply the number of turns by 1.65 (this is from the parallel triangle formed by the rocker stud and the pushrod from the valve stem) and then by .049 (I am basing this on a metric thread pitch of 1.25 mm per thread, so 1.25 mm = 0.049").
So, 1/2 turn would be 0.049/2*1.65 = 0.040
So, 1/2 turn would be 0.049/2*1.65 = 0.040
Trending Topics
Thread Starter
TECH Enthusiast
iTrader: (9)
Joined: Dec 2004
Posts: 584
Likes: 0
From: Charleston, SC
Originally Posted by oange ss
run rocker bolt down to 0 lash on lifter, position indicator pin on pushrod side of rocker arm, zero out guage, torque rocker arm bolt to recommended spec, veiw guage for preload info
Last edited by White95TA; Apr 22, 2006 at 06:31 PM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
gonna ask a question here....
what about the issue of not having the lifter pumped up with oil?
say new lifters being installed during cam swap. or if you pulled your lifters and they had some drainage. sometime just priming isnt enought to get an accurate reading.
from my (limited) understanding it can make a large diff...
???????
what about the issue of not having the lifter pumped up with oil?
say new lifters being installed during cam swap. or if you pulled your lifters and they had some drainage. sometime just priming isnt enought to get an accurate reading.
from my (limited) understanding it can make a large diff...
???????
Originally Posted by 777
Buy a pushrod length checker. $20 from www.ls1speed.com
Originally Posted by vettenuts
Either with a dial indicator, or if you can tighten the rocker until you just take out the lash, then tighten it until the slop it out of the rocker bolt (don't torque) so that you are compressing the lifter. Multiply the number of turns by 1.65 (this is from the parallel triangle formed by the rocker stud and the pushrod from the valve stem) and then by .049 (I am basing this on a metric thread pitch of 1.25 mm per thread, so 1.25 mm = 0.049").
So, 1/2 turn would be 0.049/2*1.65 = 0.040
So, 1/2 turn would be 0.049/2*1.65 = 0.040
Can you elaborate a bit more on the calc? That is, where's the 1.65 multiplier come from....I'm not following the "parallel triangle" description...
Or is this calc the correction for the 1.7 ratio rocker - holding the tip of the rocker at the valve fixed & drawing an imaginary line from the valve-tip to the pushrod-end, there is then a "triangle" generated as the rocker bolt is tightened & its amplified effect on the pushrod....?
Thanks!!!
Launching!
Joined: Dec 2005
Posts: 232
Likes: 0
From: nj, edison
i just placed midget magic markeron the flat surface of the head with the tip on the p/r made sure its steady and then tightened the rocker arm. measured the mark it left behind. bleed down of the lifter,zero lash and cam location are part of this check and fixied rocker arm design.
Originally Posted by 02RedHawk
Wait, I think I understand it now, after throwing it on paper... But I think the "1.65" should actually be "1.70" (our rocker ratio), yes?
Originally Posted by GuitsBoy
No, 1.7 is when going the other way. I get 1.588 being the ratio in this direction. How about this: Every 360* of the rocker bolt past 0 lash is .078" of preload.
