LT1-TA

im in the process of putting my new motor together and i want to check push rod length.after using my comp pr checker and a sharpie i got my mark in the center but it was at 7.00" and when i had the set screw tight for the poly lock it was sticking out so did i do this wrong? im new to this any help from the experienced appreciated. thanks,Ken

UnitZ28

Are your lifters fresh?

LT1-TA

600 miles on them (comp lifters) and i made sure they were pumped up when i checked them.

BOLO

iTrader: (40)

IMO, it's best to check pushrod length using a solid lifter.

LT1-TA

i dont have any,and i dont want to order the wrong length for a second time so i have to figure this out asap so i can get my car together correctly

BOLO

iTrader: (40)

Can you give some info on your new set up? stock block? stock heads? big cam? etc..

SoxXpupPeT

iTrader: (34)

isnt stock length 7.200" ?? What setup are you running to lose .200"?? Im running ls7 lifters and .026" head gaskets with .020" shaved off my head and im still at 7.100"

LT1-TA

i have a set of new 643 castings that i bought from golen engines,im using a LE 226/232 110lsa .574 .570 lift cam with nsa 1.6 ratio scorpion rockers,comp lifters,arp studs with comp guide plates.i have felpro head gaskets part# 1074 with a .039 thickness.motor has been rebuilt and has been decked.if im missing any info just let me know thanks

LT1-TA

like i said i could have measured wrong but i did it numerous times,golen claims the heads have been decked to 54cc but i thought thats what they were stock,the reason i bought these heads were cause the old motor was overheated and cracked one of the heads

BOLO

iTrader: (40)

I'm sure you're still pretty close to stock length, 7.200", but I'd check regardless.

gregrob

iTrader: (8)

He said the heads and block have been milled. I doubt hes still close to 7.2

I see no reason to use a solid lifter personally. You do have to have a feel for it though I suppose.

As long as you're not collapsing the lifter when you're checking, you're fine.

Make sure you're on the base circle, find zero lash with the up and down method, not the spin pushrod method, then measure...

LT1-TA

i installed the stock length pushrod,colored valve stem with a sharpie,properly adjusted the rocker and turned the motor over til the rocker went up and down twice.I then pulled it back apart and checked to see where my mark was.with the 7.2" pushrod the mark was off toward the exhaust port.i then adjusted the pushrod checker .50 at a time til i got it where i thought it should be.7.00" seemed to be the magic number and put the line in the center of the stem and i tried on different studs to see if the outcome was the same,like i said ive never done this before and i could be doing something wrong.when the rocker is adjusted with the 7.00' pushrod the set screw sticks out of the polylock when tightened down which makes me question if i did it right.

gregrob

iTrader: (8)

That is rocker / pushrod geometry, not pushrod length...

You need to measure the pushrod length independently of that, and when you get the correct length pushrod, then you may have to shim the rockers to get the perfect wipe pattern.

LT1-TA

and the intake is off so i can actually see the lifters and im 100% sure it was on the base circle when adjusting

LT1-TA

i thought the reason for getting the pushrod length correct was to make sure your valvetrain geometry is correct and that is what the comp adjustable checker is for?

gregrob

iTrader: (8)

Getting the correct length pushrod is necessary, but measuring the wipe pattern is only part of the story.

Do you have a soft test spring in the place of the valve spring? If not it could be seriously deflecting the adjustable pushrod and throwing your readings off.

To make it simple.

Bottom out the lifter when installing the adj pushrod. Keep adjusting the pushrod until you get the pattern you want (as you did) then lock the poly lock on the rocker.

Now shorten the pushrod to get zero lash as I described up there, til it no longer moves up and down freely

Now measure the adj pushrodand ADD your desired lifter preload to it.

This gives you the both the correct geometry (rocker adjustment), pushrod length and desired lifter preload.

I would however use a test spring.

Hope that helps.

LT1-TA

i dont have a test spring but ill try it after work tomorrow thanks

gregrob

iTrader: (8)

Grab one from the hardware store. Doesn't have to be super strong, just enough to see the wipe pattern on the valve tip.

hitmanws6

iTrader: (20)

I have a decked block with LEs 228/236. Heads were milled .005 for cleanup, still have 58cc chambers and im running a 7.25 pushrod. I just don't see heads that are 4ccs smaller than stock needing a .2 shorter pushrod

leadfoot4

iTrader: (1)

True, but then you have the additional variability of the solid roller lifter not being 100% dimensionally the same as the ones that he's going to use...