lifter preload
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On The Tree
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lifter preload I'm in the process on installing heads (dart pro1 205) and cam (comp 228/231 .571/.573 112) on my 98 vette and I'd like to order the new push rods ASAP. What lifter preload are you guys running and what do you recommend?
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Verdad Gallardo Thread Starter
On The Tree
Joined: Jun 2007
Posts: 177
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Thread Starter
On The Tree
Joined: Jun 2007
Posts: 177
Likes: 0
Vettenuts, NOT TRYING TO HIJACK, but I am also FINALLY getting my motor together, and this thread also apllies to me, and, many others, I'm sure. Again, NOT trying to hijack, but with some of the reported failures of the Caddy lifters (Which I am running!), is this pre-load applicable to the Caddy lifter, as well? Talked to Katech today, and was told to go to ls1howto.com and look for lifter install. I have had no luck finding it....yet. This thread would be the perfect one for someone to post up on just where this "lifter install" is, and maybe a link, to help any of us who might need it, get there. Thanks.
hehe just kidding...cool icon! Vettenuts, NOT TRYING TO HIJACK, but I am also FINALLY getting my motor together, and this thread also apllies to me, and, many others, I'm sure. Again, NOT trying to hijack, but with some of the reported failures of the Caddy lifters (Which I am running!), is this pre-load applicable to the Caddy lifter, as well? Talked to Katech today, and was told to go to ls1howto.com and look for lifter install. I have had no luck finding it....yet. This thread would be the perfect one for someone to post up on just where this "lifter install" is, and maybe a link, to help any of us who might need it, get there. Thanks.
) 
FWIW... W2W recommends only around .025 preload when the (STOCK) motor is HOT. I would imagine that with all that aluminum expanding, when the motor is cold the preload would be quite a bit more, say .040-.050 (If it is .025 COLD). In talking to Kurt Urban@ W2W, he said that they usually shoot for about one full turn down from zero lash when the motor is cold. The rocker bolts are M8-1.25, which means when you make one complete revolution of the bolt, it will travel about .050". I know that on the "traditional" small block motors, a lot of us (Me included) would loosen the rocker until it JUST started "ticking" and then we would tighten down the rockers only about 1/4-3/8 of a turn, which would make the engines rev a little higher and make a little more power on top end. This setting allows the lifter to not have to "bleed down" as much as a higher pre-load setting would do. Hope this helps!
For me: I used an pushrod length checker and when the lifter was on the base circle of the cam, I turned until she was just snug. I did the math from there and added in my desired preload.
So far so good and valvetrain is quiet. Am I just not getting it?
Please explain...
Thanks,
Frat
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On The Tree
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I have always been under the impression that lifter preload is a function of push rod length on a non adjustable valvetrain. If that is the case then why do I always read about people going "(a set amount of turns) passed 0 lash". How are they able to get the preload right and still torque the rockers to 22 ft lbs?
For me: I used an pushrod length checker and when the lifter was on the base circle of the cam, I turned until she was just snug. I did the math from there and added in my desired preload.
So far so good and valvetrain is quiet. Am I just not getting it?
Please explain...
Thanks,
Frat
For me: I used an pushrod length checker and when the lifter was on the base circle of the cam, I turned until she was just snug. I did the math from there and added in my desired preload.
So far so good and valvetrain is quiet. Am I just not getting it?
Please explain...
Thanks,
Frat
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Counting turns on non adjustable stock rockers, just lets you estimate your preload.
Rockers have to be tightened (22>24 lbs) while p-rod is on base circle.
While tightening to 22 lbs, one can count the number of turns and that gives that person an idea of preload value.
Stock rockers are NON adjustable, they just have to be tightened to 22>24 lbs, that is it. The pushrod length is what will determine the preload increase or decrease.
Rockers have to be tightened (22>24 lbs) while p-rod is on base circle.
While tightening to 22 lbs, one can count the number of turns and that gives that person an idea of preload value.
Stock rockers are NON adjustable, they just have to be tightened to 22>24 lbs, that is it. The pushrod length is what will determine the preload increase or decrease.
