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Checking for pushrod length? I'm not getting it

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Old 09-30-2011, 08:00 PM
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ok so they are all a consistent 2 and 1/4 turn from zero lash to 22 ft lbs........so my pushrods are too long, rite? do you guys think i could get away with running these for a couple of weeks or will 2 1/4 turn damage the valvetrain? i really need to get my car running, its my only means of transportation. (besides city bus)

also, in shanes explanation of finding the correct pushrod he stats if you end up with 2 1/4 turn then you need a pushrod .25'' smaller....so i should be using a 7.15? the stockers are 7.40, minus the .25'' then you get 7.15'', is this correct. i just dont remember reading about anyone using this size pushrod. any recomendations is greatly appreciated.

*note, these are newly installed lifters. they were soaked in oil for 36 hrs but they have never been run.....dont know if that makes a difference but i figured i should let it be known.

thank you,
gino
Old 09-30-2011, 08:05 PM
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Originally Posted by LilJayV10
An easier to way to make sure you are on the base circle of the cam is as one valve starts to open check the other one because it will have no lift on it.
Or try this method to get on the cam's base circle ... IMO, it's easy and straight forward.

1) Turn the engine over clockwise (looking at front of engine) until the rocker arm is all the way down (ie, valve all the way open).

2) Mark the crankshaft pulley (use a piece of tape), and then turn the crankshaft 1 full turn clockwise from that marked point.

This will turn the cam 1/2 turn, and put the lifter 180 degrees opposite the cam lobe and on the base circle well away from the cam ramps.
Old 09-30-2011, 08:24 PM
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Originally Posted by ggino85
ok so they are all a consistent 2 and 1/4 turn from zero lash to 22 ft lbs........so my pushrods are too long, rite? do you guys think i could get away with running these for a couple of weeks or will 2 1/4 turn damage the valvetrain? i really need to get my car running, its my only means of transportation. (besides city bus)

also, in shanes explanation of finding the correct pushrod he stats if you end up with 2 1/4 turn then you need a pushrod .25'' smaller....so i should be using a 7.15? the stockers are 7.40, minus the .25'' then you get 7.15'', is this correct. i just dont remember reading about anyone using this size pushrod. any recomendations is greatly appreciated.

*note, these are newly installed lifters. they were soaked in oil for 36 hrs but they have never been run.....dont know if that makes a difference but i figured i should let it be known.

thank you,
gino

Yes that is too much preload. As mentioned before 1 1/4- 1 1/2 is optimal.

With that much preload you could run the risk of bottoming the lifter out which could cause other damage.
Old 09-30-2011, 09:43 PM
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does the 7.15'' pushrod sound correct? that seems a little short. im looking a sd parts and they really only have a few sizes for ls1's 7.315'' 7.350''.....i found a 7.300 but it doesnt say if it'll work for ls1's or not. im going to go with the 7.15''s i think since they are .25'' shorter than stock and thats the calculations i came up with using the method in #1 post.

Last edited by ggino85; 09-30-2011 at 10:02 PM.
Old 09-30-2011, 10:31 PM
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Originally Posted by ggino85
also, in shanes explanation of finding the correct pushrod he stats if you end up with 2 1/4 turn then you need a pushrod .25'' smaller....so i should be using a 7.15? the stockers are 7.40, minus the .25'' then you get 7.15'', is this correct. i just dont remember reading about anyone using this size pushrod. any recomendations is greatly appreciated.
Be careful with your numbers. It's not ".25 inch" but rather 0.025" (25 thousands of an inch). There is a HUGE difference.

That means you would need 0.025" shorter than the stock 7.400" ... which would mean a 7.400 - 0.025 = 7.375" long pushrod. NOT a 7.150 !
Old 09-30-2011, 11:04 PM
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i feel like a dumb dumb.......i was just coming back to the forum to change my post lol, i was hoping no one caught it yet lol.

i was rechecking everything, i just didnt feel right with the 7.15'' and i noticed the lack of the zero in my math.....thanks for the help though zee0six, that was a close one.

i ordered the 7.350'' pushrods from sd parts, i figured since i was at a strong 2 1/4 (almost 2 1/2) turns to 22 ft lbs it wouldnt hurt to have a slightly smaller pushrod than 7.375.
Old 10-01-2011, 12:19 AM
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Have you thought about buying a pushrod?
Old 10-01-2011, 07:37 AM
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lilj, u meen a pushrod checker? if so yeah i thought about buying one but i didnt think i had a radical enough setup to really need it rite now......my 243 heads are milled .010'', the ls7 lifter are suppose to be a litte taller than the stock ls1's lifters so with those things in mind i kinda assumed i would need a slightly smaller pushrod than stock but i thought i might be able to get away with the stockers.

or....... did you mean just buying one pushrod? if so, no i didn't think of that. that would have been a better idea. i already ordered a set of 7.350'' ones so i'll cross my fingers that they work out if not i will buy a checker or go the route you mentioned and for $7.25 a piece i can buy a few different sizes and see which works best. (kinda wish i woulda done that lastnight instead of order the set of 7.350'' ones.)
Old 10-01-2011, 11:35 AM
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I meant an adjustable pushrod checker. That way you can change the length of it to get the preload you want. Different size pushrods would do the same thing but you would have to buy several different sizes. The comp cams adjustable pushrod goes from 6.8-7.8 in .050 increments. I have one and love it.



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