Lifter Preload Question
Thread Starter
Le Mans Master
Joined: Nov 2006
Posts: 5,032
Likes: 204
From: Greenwood Indiana
2021 C4 of the Year - Modified Finalist
C4 of Year Finalist (appearance mods) 2019
Lifter Preload Question
I just want to make sure I understand what this means. When you install roller rockers, the instructions say "set preload". Does this mean, tighten the rocker adj. nut until contact is first made between the lifter, pushrod and rocker-arm?
Any additional turns after making contact?
I'm putting 1.6 roller rockers and LT-4 springs on my 94 LT-1 and don't want to take the valve covers off again. Unless that's the only way to adjust the valves, (with it running).
Also, do you have to use LT-4 valve-locks if you're using the LT-4 retainers? Same as LT-1's?
Any additional turns after making contact?
I'm putting 1.6 roller rockers and LT-4 springs on my 94 LT-1 and don't want to take the valve covers off again. Unless that's the only way to adjust the valves, (with it running).
Also, do you have to use LT-4 valve-locks if you're using the LT-4 retainers? Same as LT-1's?
Last edited by johnnymo63; Apr 17, 2008 at 01:47 AM.
Melting Slicks
Joined: May 2007
Posts: 2,171
Likes: 1
From: Warwick RI
Adjusting hydraulic lifters while running I consider a last resort. Pre-load is just that. You make sure the lifter is on the base of the lobe and tighten to zero lash (many opinions on this one). The manufacturers pretty much agree that as you spin (wiggle, move up and down..whatever) the pushrod between your thumb and forefinger when you feel resistance...that is zero lash. The 1/2 - 3/4 turn should be .030 - .040 preload. Your rockers should have detailed instructions on this.
From Comp Cams instructions to get on the base of the lobe do one cylinder at a time, some do it differently and it works so this is just one manufacturer's instructions:
"When the exhaust valve begins to move, adjust the intake on that cylinder"
"When the intake valve is past max lift and is almost all the way down, adjust the exhaust on that cylinder"
Sorry for the long post
From Comp Cams instructions to get on the base of the lobe do one cylinder at a time, some do it differently and it works so this is just one manufacturer's instructions:
"When the exhaust valve begins to move, adjust the intake on that cylinder"
"When the intake valve is past max lift and is almost all the way down, adjust the exhaust on that cylinder"
Sorry for the long post
Burning Brakes
Joined: Jun 2004
Posts: 1,186
Likes: 21
From: West Tennessee
Adjusting hydraulic lifters while running I consider a last resort. Pre-load is just that. You make sure the lifter is on the base of the lobe and tighten to zero lash (many opinions on this one). The manufacturers pretty much agree that as you spin (wiggle, move up and down..whatever) the pushrod between your thumb and forefinger when you feel resistance...that is zero lash. The 1/2 - 3/4 turn should be .030 - .040 preload. Your rockers should have detailed instructions on this.
From Comp Cams instructions to get on the base of the lobe do one cylinder at a time, some do it differently and it works so this is just one manufacturer's instructions:
"When the exhaust valve begins to move, adjust the intake on that cylinder"
"When the intake valve is past max lift and is almost all the way down, adjust the exhaust on that cylinder"
Sorry for the long post
From Comp Cams instructions to get on the base of the lobe do one cylinder at a time, some do it differently and it works so this is just one manufacturer's instructions:
"When the exhaust valve begins to move, adjust the intake on that cylinder"
"When the intake valve is past max lift and is almost all the way down, adjust the exhaust on that cylinder"
Sorry for the long post
This is what I feel is the best way to adjust hyd lifters preload. I never had had to do this job with the engine running since using this method. A little time consuming but it is a 'once and done' type of method for sure.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Any additional turns after making contact?
Also, do you have to use LT-4 valve-locks if you're using the LT-4 retainers? Same as LT-1's?
Iroc57's advice is sound.
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
if you're **** (like me)
with intake manifold removed, look at the top of your hyd lifter, where the pushrod "seats"...you will see the "wire snap retainer ring" that holds the pushrod seat in the lifter...as the lifter is pre-loaded, the seat moves away (down) from the retainer and actual preload can be measured using an "L" wire feeler gauge (use a spark plug gapping "L" gauge wire tool or make your own "extended" one)
Thread Starter
Le Mans Master
Joined: Nov 2006
Posts: 5,032
Likes: 204
From: Greenwood Indiana
2021 C4 of the Year - Modified Finalist
C4 of Year Finalist (appearance mods) 2019
Thank you gentlemen. I've got used rockers (no instructions). 1/2 - 3/4 turn after zero lash, is what I was thinking, but now I'm not worried about doing it that way. 
Burning Brakes
Joined: Aug 2006
Posts: 1,061
Likes: 99
From: Seattle WA
I'd go more towards the 3/4 turn end (I think the factory manual says 1 turn past zero lash). I've done it at 1/2 turn (per comp cams instructions) and had them make noise after wear-in.
Also, you can do them all with the engine in 2 positions (1/2 at #1 firing position and the other 1/2 at #6 firing position). No need to turn the engine over for each cylinder you're adjusting.
Also, you can do them all with the engine in 2 positions (1/2 at #1 firing position and the other 1/2 at #6 firing position). No need to turn the engine over for each cylinder you're adjusting.
Burning Brakes
Joined: Aug 2006
Posts: 1,061
Likes: 99
From: Seattle WA
with intake manifold removed, look at the top of your hyd lifter, where the pushrod "seats"...you will see the "wire snap retainer ring" that holds the pushrod seat in the lifter...as the lifter is pre-loaded, the seat moves away (down) from the retainer and actual preload can be measured using an "L" wire feeler gauge (use a spark plug gapping "L" gauge wire tool or make your own "extended" one)
May not work for the OP, though, if he's just changing out rockers and not removing the intake.
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Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
I'd go more towards the 3/4 turn end ...