Pushrod length

[beanhead]

What is the proper method for checking length on a hydraulic tappet engine with non-adjustable rockers? I have a checking pushrod but haven't (needed to) done this on a stocktrain engine...but this one gets tappy and I want to verify length before assuming anything.. it does seem to get a little noisier after the engine is hot, and the heads are aluminum(Ed RPMs)..comp 274xe cam&lifters. I searched but all I can seem to find is how to do it with solids or adjustable rockers.. thanks everyone!

 

[Bill Monk]

Cam has to be on the base circle. Use an adjustable pushrod to check length with the rocker shaft tightened to specs. Set at 0 and add .040 for lifter pre-load and there's what you need.

 

[beanhead]

So by "set at 0" you mean the point where the push rod/rocker/valve tip are snugly contacting each other?

 

[Bill Monk]

yes

So by "set at 0" you mean the point where the push rod/rocker/valve tip are snugly contacting each other?

yes sir

 

[beanhead]

Okay thank you

 

[Jackpot50]

Cam has to be on the base circle. Use an adjustable pushrod to check length with the rocker shaft tightened to specs. Set at 0 and add .040 for lifter pre-load and there's what you need.

On adj rockers 5/16"-24 one turn is .042 that sounds right

 

[Zeppelin264]

Its the point where the lifter just is about to start plunging inward. You can twist the pushrod with your thumb and index finger back and forth and feel the resistance right as that event starts, usually.

From there, 3/4 to 1 full turn and your pre load is set. It's not super critical. Another way I found to adjust mine was to set 1 or 2 up and then look at the threads on the bottom of the rocker. For mine 2 threads showing is perfect lifter pre load. So when I go to set them, I just adjust it to where I know it's set correctly. Saves time with having to crank the motor etc...