pushrod length 440

[doug428]

had 8 and 15/16" pushrods that seem too short, had 5 threads showing on the crane rocker adjuster.
ordered a set of 9.125 now have no threads showing, shoud I not use either and maybe order the 9.030

 

[451Mopar]

Solid or Hydraulic cam? How much lash or pre-load.
You can calculate the length you need using the pushrods you have. First figure out the rocker arm adjuster thread pitch. If it is 20-TPI, each turn is 0.050", if it is 24-TPI, each turn in 0.0417". Using the longer 9.125" pushrod (and assuming it is adjusted with the correct lash/pre-load), count the number of turns it takes to get the number of threads showing that the rocker arms recommend. Multiply the number of turns by the number from converting the threads per inch, and subtract from the length of the pushrod. For example, If the adjusters are 20-TPI (0.050" per rev) and it takes two turns so one thread is showing that is 2x0.050 = 0.100", subtract from the 9.125" pushrod (9.125-0.100) = 9.025"

 

[Meep-Meep]

You want a pushrod length that puts the centerline of the ball and cup pivot interface on a straight line that originates from the valve tip through the center of the shaft.

 

[doug428]

You want a pushrod length that puts the centerline of the ball and cup pivot interface on a straight line that originates from the valve tip through the center of the shaft.

when i check this way at the centerline of adjuster ball, the screw threads are even with rocker with no threads sticking out.
if I align straight edge with the actual contact point of cup and ball tip then the screw is up inside the rocker too far. the threads of rocker show.

 

[Meep-Meep]

It's hard to get the ball/cup interface lined up, so in lieu of that, I just leave as little thread showing as possible. The left setup above will work fine.