Pushrod Length.. How to check correctly?
Originally Posted by ShevrolayZ28
The rubber band ends up snug between the head and the pushrod. This way it holds the lower half of the tool in place so that it doesn't turn with the upper half as you're taking up the length. You'll see what I mean when you go to it.
Originally Posted by BlkHwk
The rubber band thing worked great. I ended up with 7.288 + .030 (Lunati Lifter)= 7.318. I ordered the comp 7794 pushrod which is 7.325 which will leave me with .037 preload. Should be good I would think.
Staging Lane
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From: Redwood City, Ca.
Just for your info. I sent my adjustable pushrod to Smith Bros. and had them add 0.045 preload. Came out to 3.750. I have different rockers, the end result is I might have used more preload - my valve train is noisy.
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Originally Posted by PREDATOR-Z
If you determined 7.35 at 0 lash, then add .080 preload (average) and you got 7.455
so like i said either 7.425 or 7.450 (choose your poison)
so like i said either 7.425 or 7.450 (choose your poison)
I borrowed some stock pushrods today and tried them just to see how they fit. You can't even bolt down the rocker arms to the stand because the pushrod is way way way too long. I sat the pushrods in and laid the rockers on top of them and rotated the motor 2 complete times and the pushrods never went down far enough for the rocker arms to sit down on the stand..
So there is no way in hell that a 7.425 would work at all...
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From: BFE
Originally Posted by 1QuickT-A
I checked it again today with some dial calipers and it was a little shorter than what I thought yesterday.. I'm gonna use some 7.35's and see how that works.
I borrowed some stock pushrods today and tried them just to see how they fit. You can't even bolt down the rocker arms to the stand because the pushrod is way way way too long. I sat the pushrods in and laid the rockers on top of them and rotated the motor 2 complete times and the pushrods never went down far enough for the rocker arms to sit down on the stand..
So there is no way in hell that a 7.425 would work at all...
I borrowed some stock pushrods today and tried them just to see how they fit. You can't even bolt down the rocker arms to the stand because the pushrod is way way way too long. I sat the pushrods in and laid the rockers on top of them and rotated the motor 2 complete times and the pushrods never went down far enough for the rocker arms to sit down on the stand..
So there is no way in hell that a 7.425 would work at all...
IF your 0 lash measurement is 7.375 THEN add preload.
If your 0 lash measurement is wrong then it is another story.
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Originally Posted by PREDATOR-Z
As I said:
IF your 0 lash measurement is 7.375 THEN add preload.
If your 0 lash measurement is wrong then it is another story.
IF your 0 lash measurement is 7.375 THEN add preload.
If your 0 lash measurement is wrong then it is another story.
I also took a stock ls1 lifter and measured the preload on it and got twenty thousanths out of it.. A reputable shop also told me that twenty thousanths of preload is all that an LSX engine would need. No more than that..
So I guess that I really need a 7.375...
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From: Birmingham, Alabama
Originally Posted by PREDATOR-Z
If you determined 7.35 at 0 lash, then add .080 preload (average) and you got 7.455
so like i said either 7.425 or 7.450 (choose your poison)
so like i said either 7.425 or 7.450 (choose your poison)
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Joined: Mar 2004
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From: BFE
.020 movement, yeah right???
I measured preload on a stock motor and it was .1 and stock lifters can handle up to .120 (I use as close to .080 to leave a little room on pump up with a higher reving cam)
But are you using stock rockers?
Duh, I just read the post again and you are using Jessels. My mistake
,
Still they are non adjustable, 7.40's should work and give you .050 preload.
THAT is if 7.350 is CORRECT at 0 lash.
Now since you say that 7.40 are so long that the rocker wont even bolt on, then i doubt you have the 7.350 measurement correct.
I measured preload on a stock motor and it was .1 and stock lifters can handle up to .120 (I use as close to .080 to leave a little room on pump up with a higher reving cam)
But are you using stock rockers?
Duh, I just read the post again and you are using Jessels. My mistake
, Still they are non adjustable, 7.40's should work and give you .050 preload.
THAT is if 7.350 is CORRECT at 0 lash.
Now since you say that 7.40 are so long that the rocker wont even bolt on, then i doubt you have the 7.350 measurement correct.
Last edited by PREDATOR-Z; Sep 21, 2006 at 04:13 AM.
i have the comp pushrod checker and im going to set it out to 7.30 then bolt down the rocker and check the thousands on the rocker to valve spot. I think this way will be most acurate and with comp rs I dont have much room to play with.
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Originally Posted by PREDATOR-Z
.020 movement, yeah right???
I measured preload on a stock motor and it was .1 and stock lifters can handle up to .120 (I use as close to .080 to leave a little room on pump up with a higher reving cam)
But are you using stock rockers?
Duh, I just read the post again and you are using Jessels. My mistake ,
Still they are non adjustable, 7.40's should work and give you .050 preload.
THAT is if 7.350 is CORRECT at 0 lash.
Now since you say that 7.40 are so long that the rocker wont even bolt on, then i doubt you have the 7.350 measurement correct.
I measured preload on a stock motor and it was .1 and stock lifters can handle up to .120 (I use as close to .080 to leave a little room on pump up with a higher reving cam)
But are you using stock rockers?
Duh, I just read the post again and you are using Jessels. My mistake
, Still they are non adjustable, 7.40's should work and give you .050 preload.
THAT is if 7.350 is CORRECT at 0 lash.
Now since you say that 7.40 are so long that the rocker wont even bolt on, then i doubt you have the 7.350 measurement correct.
With the pushrod checker 11 complete turns out you get 7.350.. When I had it in the head with the rocker arms bolted down there was no slack in the rocker arm at all and the geometry looked fine. I even called a ProModified racer and engine builder and he came and looked at it and said everything looked and felt fine.
