Pushrod length and lifter preload on this setup
Thread Starter
Launching!
Joined: Nov 2008
Posts: 284
Likes: 1
From: Pembroke pines FL
Pushrod length and lifter preload on this setup So I am finishing up my 02 z06 head and cam swap. I have the heads on and I measured the pushrod length using a pushrod checker tool by comp cams. thing is that I am getting two different measurements for intake and exhaust. I made sure that both intake and exhaust were on base circle. I got 9.5 turns for intake and 9 turns for exhaust to get to zero lash. I think this may be because my intake is LS3 turned down and the exhaust are ferrea stainless and the valve heights may be different. The lifters I am using are LS7 lifters.
If i average out the turns to 9.25 I basically have to choose between a 7.350 or a 7.325 length pushrods depending on the preload.
If I go with 7.350 the intake side will be preloaded .075" and exhaust will have .100 preload
if I go with 7.325" the intake side will have .050" preload and the exhaust will have .075" preload.
Which of these setups would be best? has anyone running a similar setup seen this phenomenon? the cam is 228/230 .571/.573 on 112 LSA and 110 ICL btw and the springs are PSI 1511ML. The lifters are LS7 lifters btw.
If i average out the turns to 9.25 I basically have to choose between a 7.350 or a 7.325 length pushrods depending on the preload.
If I go with 7.350 the intake side will be preloaded .075" and exhaust will have .100 preload
if I go with 7.325" the intake side will have .050" preload and the exhaust will have .075" preload.
Which of these setups would be best? has anyone running a similar setup seen this phenomenon? the cam is 228/230 .571/.573 on 112 LSA and 110 ICL btw and the springs are PSI 1511ML. The lifters are LS7 lifters btw.
Last edited by VerdeZ28; Jan 3, 2014 at 04:15 PM. Reason: lifters not specified
getting different lengths is normal. all 8 pairs of mine had between .020-.030" difference on average (exhaust were shorter).
if I'm reading this correctly your 9.5 and 9 turn measurements were at zero lash, correct? to get the appropriate length with preload, you'd have to add whatever you want on top of your zero lash measurement.
closed length + (#turns * .050) + desired preload = final length
What is best depends on what lifters you're using.
if I'm reading this correctly your 9.5 and 9 turn measurements were at zero lash, correct? to get the appropriate length with preload, you'd have to add whatever you want on top of your zero lash measurement.
closed length + (#turns * .050) + desired preload = final length
What is best depends on what lifters you're using.
It's not uncommon. It's probably less the valves (I have LS3 intake and Ferrea exhaust and don't recall there being a difference), and more the cam lobes may be different intake to exhaust.
I'd order what you need for ideal preload. Go to Manton or Trend and get custom pushrods.
I'd order what you need for ideal preload. Go to Manton or Trend and get custom pushrods.
Thread Starter
Launching!
Joined: Nov 2008
Posts: 284
Likes: 1
From: Pembroke pines FL
Thanks for the response guys. So now that I feel ok with getting different measurements, what preload should I shoot for with the LS7 lifters? I am looking to achieve best valvetrain stability possible.
I had the same issue last year using Manley valves. I ended up using two different size pushrods to get the preload correct and the funny thing is I was running the same cam that you are now. If you are interested, I changed my whole setup and I have no use for the pushrods anymore. I have 8- 7.325, 8- 7.350, and 8- 7.375 I will let them go cheap. I don't even think they have 500 miles on them.
Trending Topics
Thread Starter
Launching!
Joined: Nov 2008
Posts: 284
Likes: 1
From: Pembroke pines FL
I double checked it making sure the the timing was right so that I would be on the base circle of the cam and I came up with 9.25 turns for both intake and exhaust.
For what's readily available I can go with .063" preload or .088". Which should I go with?
For what's readily available I can go with .063" preload or .088". Which should I go with?
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
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
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
