Step by step? Time to put that worry put to bed. Any help is appreciated.


I have the tool on loan from a great CF member.

TIA



Brad

 

id like to know as well.

 

Assuming stock rockers-

First, the rules of engagement:

1. There should be two white lines on the adjustable pushrod that match when fully closed, this is the base length (the Comp is 6.800")
2. Measurements are in gauge length, so you need to use the rotations beyond the base length to determine your length requirement by counting turns. Gauge length is taken at the ball diameter, typically where it is 0.140" in diameter.
3. Each turn is 0.050" in length change.
4. Measurements are done with the lifter on the cam base circle so make sure the valve you are checking is fully closed

Method:

1. Crank out adjustable pushrod until it is approximately the same length as your stock pushrod, then shorten it by three turns
2. Get three rockers, three bolts and the rocker stands, install the stand onto the head
3. Put the adjustable pushrod into the lifter hole that you are checking (gently push down to make sure lifter is against cam) and then put the rockers on this position and the adjacent rocker positions (no pushrods here, it is only to ensure the stand it parallel and flat.
4. Tighten the rockers to around 10 lb-ft, you don't need to fully torque as a bolt preload is not required.
5. The adjustable pushrod should be loose at this point and you can move it slightly up and down, if you can't then remove this rocker only and turn in another turn on the pushrod (repeat as necessary).
6. Once the rocker is in place and the pushrod is loose, open the pushrod to attain zero lash. Best way to confirm is to gently pick up the rocker tip at the valve (picking up too hard can compress the lifter plunger, especially on new lifters so very gentle here). If there is a tick tick then you aren't at zero lash. Just open the pushrod until you take out the tick tick. (Note: If you can't do this with the rocker in place, you will need to remove the rocker, slightly open the pushrod and then put it back together to check for zero lash, repeating as necessary).
7. Once you have the pushrod so you are at zero lash, remove the rocker and carefully remove the pushrod.
8. Count the turns down to fully closed.
9. For example, lets assume you have 10.5 turns to get the adjustable pushrod fully closed, you would have:

Base length + adjusted length = zero lash length

or

6.800" + 10.5 X 0.050" = 7.325" for your zero lash length

10. You now need to add in your lifter preload, for stock lifters lets assume you want 0.100" preload.

Zero lash length + lifter preload = Final length

7.325" + 0.100" = 7.425"

11. This is the final pushrod length. Note that if you measure it with a caliper this number will be different because it is gauge length, not overall length.

 

Vette, great help, thank you. However I am an idiot. I should have said with HS 1.7 roller rockers. Although 1.7 is the stcok ratio correct? Same procedures?

Thanks again for posting the excellent help.



Brad

 

GREAT write up!!

 

Thanks!!!

BC

 

Same basic procedure, but I believe the HS are mounted in pairs so you only need to mount the pair. This method should work with any fixed fulcrum rocker. With an adjustable (the Cranes for example), the pushrod controls the wipe pattern and the preload.

Since you are running HS, you should verify the wipe pattern prior to measuring for the pushrod as any shimming required will also alter the pushrod length.