Question: How to measure Push Rod Lengh

**DRRummel** · 07-03-2007, 12:23 PM

I am thinking of setting up another motor.
306 roller block
Stock lifters
AFR 185 Heads with upgraded springs and valves
CompCam XE266HR
Crane Aluminum 1.6:1 roller rockers on 7/16 studs.
Gt40 upper and lower intake
2.5 inch exhaust
3.73 or 4.10 gears

I have a basic idea how to build and use an adjustable push rod when used with an solid lifter, but how do you get the valve train geometer correct when the hydraulic lifter is not pumped up. And if you manually pump up the lifters and put them in the block, won't they collapse when you spin the crank? Thanks for the help.

**SonofaBish** · 07-03-2007, 12:29 PM

Originally Posted by DRRummel

I am thinking of setting up another motor.
306 roller block
Stock lifters
AFR 185 Heads with upgraded springs and valves
CompCam XE266HR
Crane Aluminum 1.6:1 roller rockers on 7/16 studs.
Gt40 upper and lower intake
2.5 inch exhaust
3.73 or 4.10 gears

I have a basic idea how to build and use an adjustable push rod when used with an solid lifter, but how do you get the valve train geometer correct when the hydraulic lifter is not pumped up. And if you manually pump up the lifters and put them in the block, won't they collapse when you spin the crank? Thanks for the help.

from my experience with LSx motors, which is roller lifters, no, they won't collapse .... just get a pushrod length checker... make sure you are on the base circle of the cam... put ur pushrod length checker in there, tighten the rocker down to the right spec, then extend the length of the checker... add preload to this number and you have your correct length

**9002stang** · 07-03-2007, 09:17 PM

I used some checking springs when I did my PR'ds. You will need to take a set from the intake/exhaust on your head, and replace them with the lighter compression springs. They are inexpensive, around 15-20 $$ I think. Thats one way of doing it. I used a digital caliper (around $40??) which helped a great deal when comparing the different lengths that my adj. push rod was at. Im sure that the more experienced engine builders will chime in-

**wick** · 07-03-2007, 10:12 PM

I just used a dial indicator for mine. Used the old rod, loosend the lock on the roller rocker, let the rocker rest on the pushrod. Lifted it until it was in the right place and took measurment. I needed a .250 longer rod. Trickflow, $98.00.