pushrod length

[qwikz28]

how would i know if my car did not have the correct pushrod length? my car didn't make the power it should have on the dyno and still has a wicked valvetrain noise that sounds like a mix of a very fast knock and a header leak. eastside blamed my aftermarket rockers, but i don't buy that. i think my pushrods are the incorrect size. car has ls7 lifters which are supposed to be a oem replacement. yella terra rocker arms which advertises that changing the pushrods may be needed. and also the heads were milled .007 to be true. but thats an insignificant difference. eastside said to put the stock rockers on and report back to them. any ideas?

[GP99GT]

http://store.summitracing.com/egnsea...nresults=false

have at it. ONLY way to know for sure is to check it, same with piston/valve clearance, and other valvetrain stuff. some things work for one person, doesnt for the other.

[johnjzjz]

a push rod checker is for next to stock settings and most are china made so JUNK -- you may want to do it this way - take out the plugs so motor turns over easer than with, rotate it in direction of rotation to TDC #1 - \ the # 1 cylinder timing marks are right their - you will need a 1 inch travel dial indicator with a magnet bottom - alloy heads you need to hold dial stem somehow -- place it so the dials pointer is as straight as possible to the valve stem and have the pointer stop on the valve spring retainer -- the idea is you want to follow the valve up and down - intake and exhaust -- you will need to do both -- set the dial at zero now turn the motor in normal rotation direction and watch the counter on the dial lets say its 4 1/2 turns around / or .450 thousands is the max cam valve lift - now back the motor up reverse direction 2 1/4 turns or .225 ( the idea is to be in the center of the cam - valve lift ) i know the chain might be loose its not going to be perfect but don't measure the slop distance into the mix -- so you can achieve 1/2 lift only -- the correct push rod length is center of valve stem to center of rocker tip @ 1/2 what ever the cam lobe lift at the rocker is ---- you want the rocker arm tip in the center of the valve tip @ 1/2 cam lift - if it really favors the inside ( twards the intake manifold ) the valve to tip center -- the push rod is to short -- outside ( twards the exhaust manifold ) its to long the push rod -- in the end to see what size you do need you will need an adjustable pushrod and checker springs to determine the difference in length pushrods come in -- pushrods come in plus or minus .050 STD lengths -- its not hard and i hope i explained it so you get how to do it -- jz

[qwikz28]

Originally Posted by johnjzjz

a push rod checker is for next to stock settings and most are china made so JUNK -- you may want to do it this way - take out the plugs so motor turns over easer than with, rotate it in direction of rotation to TDC #1 - \ the # 1 cylinder timing marks are right their - you will need a 1 inch travel dial indicator with a magnet bottom - alloy heads you need to hold dial stem somehow -- place it so the dials pointer is as straight as possible to the valve stem and have the pointer stop on the valve spring retainer -- the idea is you want to follow the valve up and down - intake and exhaust -- you will need to do both -- set the dial at zero now turn the motor in normal rotation direction and watch the counter on the dial lets say its 4 1/2 turns around / or .450 thousands is the max cam valve lift - now back the motor up reverse direction 2 1/4 turns or .225 ( the idea is to be in the center of the cam - valve lift ) i know the chain might be loose its not going to be perfect but don't measure the slop distance into the mix -- so you can achieve 1/2 lift only -- the correct push rod length is center of valve stem to center of rocker tip @ 1/2 what ever the cam lobe lift at the rocker is ---- you want the rocker arm tip in the center of the valve tip @ 1/2 cam lift - if it really favors the inside ( twards the intake manifold ) the valve to tip center -- the push rod is to short -- outside ( twards the exhaust manifold ) its to long the push rod -- in the end to see what size you do need you will need an adjustable pushrod and checker springs to determine the difference in length pushrods come in -- pushrods come in plus or minus .050 STD lengths -- its not hard and i hope i explained it so you get how to do it -- jz

lol that sounds difficult. i tried the pushrod length checker. i own it. the problem is that the rocker arms adjust so its so hard to find. i guess i'll just give the stock rockers a try. thanks guys

[Fast92RS]

Heres a short cut I learned that will get you in the area. Take a sharpie and mark the top of the valve. Place the rocker on and adjust the lash. now rotate the engine over a few times opening and closing that valve. Then take the rocker off and check the mark you made with the sharpie. The rocker would wear some of the marking off and if that area is pefectly in the center of the valve its the right pushrod length. If not adjust the pushrod length checker until you do.


http://www.circletrack.com/techartic...gth/index.html

[johnjzjz]

Originally Posted by Fast92RS

Heres a short cut I learned that will get you in the area. Take a sharpie and mark the top of the valve. Place the rocker on and adjust the lash. now rotate the engine over a few times opening and closing that valve. Then take the rocker off and check the mark you made with the sharpie. The rocker would wear some of the marking off and if that area is pefectly in the center of the valve its the right pushrod length. If not adjust the pushrod length checker until you do.

http://images.circletrack.com/techar...s_too_high.jpg

http://www.circletrack.com/techartic...gth/index.html

that works well with solid type lifters - IE set lash -- hyd lifters sponge some of the cam lift with out oil pressure and i think its a hyd cam he dident say -- we always use a solid lifter when checking and his motor is together not easy with alloy heads getting a lifter in and out of dizy hole just to check -- but it can be done if he uses 7 or 8 to check it with -- jz

[Tru2Chevy]

Originally Posted by johnjzjz

that works well with solid type lifters - IE set lash -- hyd lifters sponge some of the cam lift with out oil pressure and i think its a hyd cam he dident say -- we always use a solid lifter when checking and his motor is together not easy with alloy heads getting a lifter in and out of dizy hole just to check -- but it can be done if he uses 7 or 8 to check it with -- jz

No need to worry about getting it in and out of the dizzy hole.....it's an LS1. He should be able to pop off the intake and valley cover pretty easily to get access to the lifters. LS1s have a dry intake, so no need to worry about coolant or anything else when R&Ring them.

- Justin

[johnjzjz]

Originally Posted by Tru2Chevy

No need to worry about getting it in and out of the dizzy hole.....it's an LS1. He should be able to pop off the intake and valley cover pretty easily to get access to the lifters. LS1s have a dry intake, so no need to worry about coolant or anything else when R&Ring them.

- Justin

i dident know it was an lt motor - being a dynosaw hahahahahah i think sbc thanks -- jz

[qwikz28]

Originally Posted by Tru2Chevy

No need to worry about getting it in and out of the dizzy hole.....it's an LS1. He should be able to pop off the intake and valley cover pretty easily to get access to the lifters. LS1s have a dry intake, so no need to worry about coolant or anything else when R&Ring them.

- Justin

fastrs- thats genius. i'm gonna try that this week... ibut i thought i'm not gonna be touching the lifters? just the pushrods and rockers