Pushrod length doesnt seem right(Using a checker!!!)
Pushrod length doesnt seem right(Using a checker!!!) Ok guys i am trying to check for the correct length pushrods.
I have the comp cams length checker that goes from 6.800 to 7.800.\
Each turn of the checker is .050.
I am checking an exhaust valve. I watched the intake valve open, so i know the exhaust is on the base circle.
Here is what i came up with.
had to turn out checker 9 full turns.
9 turns @ .050 a turn should be ----------.450
Push rod lenth checker closed -----------6.800
total with no preload--------------------7.250
add in about .065 preload(LS7 lifter)-----7.315 pushrod over all length.
This seems way off from what TFS recomends for their heads and cam package, they reccomend 7.500
Car had a TFS cam, TFS 205cnc heads and stock rockers.
Please let me know if I am doing something wrong.
TIA
Josh
I have the comp cams length checker that goes from 6.800 to 7.800.\
Each turn of the checker is .050.
I am checking an exhaust valve. I watched the intake valve open, so i know the exhaust is on the base circle.
Here is what i came up with.
had to turn out checker 9 full turns.
9 turns @ .050 a turn should be ----------.450
Push rod lenth checker closed -----------6.800
total with no preload--------------------7.250
add in about .065 preload(LS7 lifter)-----7.315 pushrod over all length.
This seems way off from what TFS recomends for their heads and cam package, they reccomend 7.500
Car had a TFS cam, TFS 205cnc heads and stock rockers.
Please let me know if I am doing something wrong.
TIA
Josh
Push down on the adjustable and make sure the lifter is on the cam. New lifters will stick in the up position. Check intake, it should be similar.
Last edited by vettenuts; Sep 5, 2009 at 11:01 AM.
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I am assuming you have the heads torqued down with head gaskets installed. Try measuring the push rod with a caliper to make sure it is accurate. You cant always use what is recomended thats why you use a pushrod checker. Also I believe trick flow rocomends using roller rockers so the length may be different for stock rockers.
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From: Bergen County, NJ
I don't know what lifters you are using but .080 to .100 is the recommended preload for LS1 lifters .075 to .120 is the range. so 7325 or 7350 would work. you can also double check by tightening rocker arm bolt to 0 lash then you should be 1 to 1.5 turns to 22 ft lbs.
Not sure that the length is way off at 7.3X.
There are lots of variables and as long as you measured should be ok. Don't go by TFS 7.500" recommendation. Didn't work for me either - little different setup but I am running 7.37 with TFS heads.
There are lots of variables and as long as you measured should be ok. Don't go by TFS 7.500" recommendation. Didn't work for me either - little different setup but I am running 7.37 with TFS heads.
Intake stroke- intake valve open then closes to compression stroke. so check exhaust
exhaust stroke- exhaust valve opens after compression stroke so you can check intake.
I need to double check everything but the intake measurement was coming up at like 7.400. I must have not been on the base circle on the exhaust.
I have been trying to bump it over and watch the valves myself. I will have some help tonight or tomorrow to try and get it right.
I have been trying to bump it over and watch the valves myself. I will have some help tonight or tomorrow to try and get it right.
I need to double check everything but the intake measurement was coming up at like 7.400. I must have not been on the base circle on the exhaust.
I have been trying to bump it over and watch the valves myself. I will have some help tonight or tomorrow to try and get it right.
I have been trying to bump it over and watch the valves myself. I will have some help tonight or tomorrow to try and get it right.
