Finding pushrod length, HELP!
01-01-2009, 11:39 PM
#1
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Finding pushrod length, HELP! hey, so i feel a little dumb on this subject lol. i got the heads on tonight so now i'm trying to figure out how to find the pushrod length, and i'm lost haha. I just don't understand where i should start for the length? I thought it would be around 7.2 inches but i dont understand how i know what the right length is, I thought the roller tip on the rocker was supposed to be in the center of the valve correct? I have the adj pushrod to find the length just dont know where to start, any help here is appreciated lol.
01-01-2009, 11:51 PM
#2
paint the valve tip with a sharpie and just try different lengths. you want the mark to be as thin and close to center as possible iirc. there are a few good threads i read awhile back if you can find them.
01-01-2009, 11:57 PM
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Heres what i found in circle track mag.
"Whether you are using a checking pushrod or a standard piece that you think might fit correctly, begin by coloring the valve tip with either a Sharpie or machinist's dye. Then, install the pushrod and rocker arm while the lifter is on the base circle of the cam. If you are using a solid lifter, set the valvetrain to zero lash. If you are running a hydraulic lifter, tighten down the rocker adjuster to your normal preload. Using a wrench on the nose of the crank, turn the motor over several times, then remove the rocker and check the mark left on the valve tip. The roller tip on the rocker should have left a shiny spot where it wore away the ink you placed on the valve tip.
If the pushrod length is correct, this mark should be centered across the top of the valve stem. If it is too high (closer to the lifter valley), try a slightly longer pushrod or lengthen the checker. If it is too low (closer to the exhaust ports), try a slightly shorter pushrod. Now simply repeat the process, adjusting the pushrod length each time, until you have the wear mark centered on the valve tip. Sometimes the low-tech methods really are the best."
"Whether you are using a checking pushrod or a standard piece that you think might fit correctly, begin by coloring the valve tip with either a Sharpie or machinist's dye. Then, install the pushrod and rocker arm while the lifter is on the base circle of the cam. If you are using a solid lifter, set the valvetrain to zero lash. If you are running a hydraulic lifter, tighten down the rocker adjuster to your normal preload. Using a wrench on the nose of the crank, turn the motor over several times, then remove the rocker and check the mark left on the valve tip. The roller tip on the rocker should have left a shiny spot where it wore away the ink you placed on the valve tip.
If the pushrod length is correct, this mark should be centered across the top of the valve stem. If it is too high (closer to the lifter valley), try a slightly longer pushrod or lengthen the checker. If it is too low (closer to the exhaust ports), try a slightly shorter pushrod. Now simply repeat the process, adjusting the pushrod length each time, until you have the wear mark centered on the valve tip. Sometimes the low-tech methods really are the best."
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01-02-2009, 01:45 PM
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U should use a solid lifter and snug the nut up. If you just set the rocker on the stud and turn the motor the rocker will just slide on the stud instead of transfering the motion to the valve.