Anybody run .040 or less preload w/ "LS7" lifters?
06-01-2010, 12:25 PM
#1
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Anybody run .040 or less preload w/ "LS7" lifters? recomended is .060 to .100, I measured with piston at tdc of exhaust stroke
and bought and installed pushrods. anyway my resultant preload is .043.
anybody have good / bad results to share with similuar setup?
and bought and installed pushrods. anyway my resultant preload is .043.anybody have good / bad results to share with similuar setup?
06-01-2010, 10:45 PM
#2
just to make sure you measured everything right what was the amount of turns of the rocker bolt after zero lash...
also you are supposed to order your pushrods after you measure oops
also you are supposed to order your pushrods after you measure
oops
06-02-2010, 08:48 AM
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to the OP, I had right at 45 preload on mine for a while and decided to tighten them up. i went to around 80 and alot of tick went away(sewing machine noise) and the car seemed more on its toes also. i recommend running on the higher preload margin. my .02 though
Good luck
06-02-2010, 08:57 AM
#4
If they are using ls7 lifters then i think its safe to say that he has an lsx motor with non-adj rockers. they are torque specific.
to the OP, I had right at 45 preload on mine for a while and decided to tighten them up. i went to around 80 and alot of tick went away(sewing machine noise) and the car seemed more on its toes also. i recommend running on the higher preload margin. my .02 though Good luck
to the OP, I had right at 45 preload on mine for a while and decided to tighten them up. i went to around 80 and alot of tick went away(sewing machine noise) and the car seemed more on its toes also. i recommend running on the higher preload margin. my .02 though
Good luck
06-02-2010, 04:14 PM
#5
Yeah, Chris knows that he has an LS engine. The method he described is how you determine preload. You are right in that you can't adjust it with the stock rockers, but you can determine how much is there. Chris was just saying to double check and make sure his measurement was accurate.
06-02-2010, 09:28 PM
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the second time I checked correctly with lifters on base cicle (and new "short" pushrods) and it took 330 degrees before final torque. so using vettenuts formula: ((330-120) / 360 ).078 = .045 or jasons @ thunder formula (330/360).047 = .043 preload.
I talked to Phil @ AI who built my heads (and has been extremely helpful
). They typically run .015 to .020. So I'm going to try my .040 ish set-up and see if it's any noiser than my previous set-up.
06-02-2010, 10:23 PM
#7
thanks, i did measure before i bought pushrods, unfortunately i discovered later that piston was @tdc of exhaust stroke not tdc of compression so valves were not on their base circle.
the second time I checked correctly with lifters on base cicle (and new "short" pushrods) and it took 330 degrees before final torque. so using vettenuts formula: ((330-120) / 360 ).078 = .045 or jasons @ thunder formula (330/360).047 = .043 preload.
I talked to Phil @ AI who built my heads (and has been extremely helpful). They typically run .015 to .020. So I'm going to try my .040 ish set-up and see if it's any noiser than my previous set-up.
the second time I checked correctly with lifters on base cicle (and new "short" pushrods) and it took 330 degrees before final torque. so using vettenuts formula: ((330-120) / 360 ).078 = .045 or jasons @ thunder formula (330/360).047 = .043 preload.
I talked to Phil @ AI who built my heads (and has been extremely helpful
). They typically run .015 to .020. So I'm going to try my .040 ish set-up and see if it's any noiser than my previous set-up.I think you will be fine at .04x but that is just crazy pushing it that low...I thought I was running it loose at .030 with my morels...but then again people run .040 ptvc with the donkey cams, way to close for comfort for me...what is the problem with selling the pr's you have now and getting a new set...we are talking like maybe $30-$40 difference at most...
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06-02-2010, 11:23 PM
#8
why would they only run .015 on a ls7 lifter...what is the benefit?
I think you will be fine at .04x but that is just crazy pushing it that low...I thought I was running it loose at .030 with my morels...but then again people run .040 ptvc with the donkey cams, way to close for comfort for me...what is the problem with selling the pr's you have now and getting a new set...we are talking like maybe $30-$40 difference at most...
I think you will be fine at .04x but that is just crazy pushing it that low...I thought I was running it loose at .030 with my morels...but then again people run .040 ptvc with the donkey cams, way to close for comfort for me...what is the problem with selling the pr's you have now and getting a new set...we are talking like maybe $30-$40 difference at most...
06-03-2010, 06:05 AM
#9
Super Stock guys do extreme preloads, it kinda acts like a solid lifter but I don't feel the risk in durability is worth it outside of racing only arenas. I think they usually run them almost bottomed out typicaly but I have also heard of little to no preload at all.
or block the oil galley...run a standard lifter with a long pushrod so when the rocker is tight the lifter is collapsed...it will never prime up and upon inspection it will still feel like a hydraulic lifter pushing on the pushrod with the small internal spring...
Last edited by chrs1313; 06-03-2010 at 07:15 AM.
