does this pushrod length sound correct?
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Launching!
Joined: Jun 2013
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does this pushrod length sound correct? I have a lq4 with 243 take off heads and a comp 224/224-581/581 on 113 cam , I bought a set of .080 tooley 7.4 rods last year for this build before I even thought about measuring for pushrods ( dumb mistake I know). so I bought a checker and using the eoic method its showing that at zero lash im at 7.343 before the lifters are preloaded ( atk ls1 replacement lifters ) so does that meen that I should be ok with my 7.4 rods ?
Have you added your desired preload and installed the checker at that length, then measure how much the bolt turns from zero preload before it bottoms out (ie: requires force to continue)? If so, how far does the bolt turn? If not, read this for more detail on measuring, starting at post #13: https://ls1tech.com/forums/generatio...l#post19085422
Use Darth's examples with your own numbers and see how they come out. Measure all of your pushrods and keep them in order. You'll see their lengths vary slightly, which could mean they're shorter or longer than 7.400. After following the guide, you'll know if you can use the pushrods you have.
Use Darth's examples with your own numbers and see how they come out. Measure all of your pushrods and keep them in order. You'll see their lengths vary slightly, which could mean they're shorter or longer than 7.400. After following the guide, you'll know if you can use the pushrods you have.
If you come up with 7.343 @ zero lash, then 7.4 is a tad short with LS stock replacement lifters using .080 pre load. You will need a 7.425.
Last edited by kinglt-1; Jun 8, 2016 at 02:33 PM.
Launching!
Joined: Apr 2015
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That's an indication that the pushrod is too long or the lifter isn't on the heel of the cam. Use the pushrod checker to get an idea on where to start measuring. Adjust the pushrod so that there is just slight play between the rocker and the pushrod with the rocker firmly seated on the pedestal. You can do that by holding the rocker on the pedestal with your hand. Once you get to that point, adjust the pushrod until you get zero lash.
Last edited by unit; Jun 8, 2016 at 04:36 PM. Reason: Corrected spelling
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Launching!
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Yes. After you have found zero lash with the adjustable pushrod, add your desired preload and that gives the length of the pushrod. Set the adjustable pushrod to the length you just calculated and try it. You should get 1 to 1.5 turns if using stock lifters. Your 7.4" pushrods may be just fine if you have 1.5 turns and no more. Be sure to check both intake and exhaust pushrod lengths.
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Launching!
Joined: Jun 2013
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It's a little less than 1.5 turns it's inbetween 1.25 and 1.5 turns . I'm gunna roll with the 7.4 rods I have and see what happens if my calculations are correct that's .057 of preload on stock lifters that should be be ok .
Hope that answers what you were asking as there seems to be some confusion here within the thread.
I have a lq4 with 243 take off heads and a comp 224/224-581/581 on 113 cam , I bought a set of .080 tooley 7.4 rods last year for this build before I even thought about measuring for pushrods ( dumb mistake I know). so I bought a checker and using the eoic method its showing that at zero lash im at 7.343 before the lifters are preloaded ( atk ls1 replacement lifters ) so does that meen that I should be ok with my 7.4 rods ?
TECH Junkie
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From: Iowa
Go until the exhaust valve is at max lift. If you check just when the exhaust valve starts to open, if you have any overlap, you won't quite be on the base circle of the cam and that can lead to some discrepancies in your numbers
[Rant]
Why do people keep measuring with the rotations and including bolt torque? When you're torquing the bolt you're no longer adding preload, but stretching the bolt. Then, minor variations in threads, debris, etc contribute to measured torque. Bolt torque and lifter preload are mutually exclusive. One does not help determine the other in either direction
[/rant]
If you're trying to verify preload with bolt rotations, find zero lash - I.e. Dead soft touch with the rocker bolt. Mark the bolt, and tighten it till it just bottoms out. .076" per bolt rotation or .019" for every 90 degrees if that's easier. then, after you've decided you have what you want, torque the bolt properly.
Why do people keep measuring with the rotations and including bolt torque? When you're torquing the bolt you're no longer adding preload, but stretching the bolt. Then, minor variations in threads, debris, etc contribute to measured torque. Bolt torque and lifter preload are mutually exclusive. One does not help determine the other in either direction
[/rant]
If you're trying to verify preload with bolt rotations, find zero lash - I.e. Dead soft touch with the rocker bolt. Mark the bolt, and tighten it till it just bottoms out. .076" per bolt rotation or .019" for every 90 degrees if that's easier. then, after you've decided you have what you want, torque the bolt properly.