Thread is six months old. Your cheeseburger is kind of stale.

 

so you set to lifters to zero lash, then w/a dial indicator tighten the lock nut watching the dial indicator until it goes to .100. is that the jist of setting pre load, or am i way off base.

 

cheezbrgr2

 

if you don't know the answer to the question why don't you keep your ******* comments to your self.

 

Red is my edit...I THINK this is what your are asking...... This will tell you how to measure PR length so have proper prelaod

Originally posted by vettenuts. You also need an adjustable pushrod checker from a sponor for about $20-$25.

Once PR length has been determined for desired preload the rocker arms are tightened to 22 ft.lbs. Search on this forum for the proper method. There are a couple ways But I think the GM recommended is prolly best.

Thanks vettenuts..... more good info coming from you.... Here ya go.....

Shamelessly stolen from Vettenuts on Corvetteforum by uncle John and swiped again by SOMbitch. Just (Uncle John) used this procedure yesterday. Works as advertised.


Each turn of the pushrod (checker) is 0.050". When fully closed, it is 6.800". This is pushrod "gauge length" so you can't measure it directly as the pushrod length is actually based on the length between the ball ends where the ball end measures 0.140" in diameter. Assuming you are using stock rockers or a non-adjustable rocker with a correctly established wipe pattern.

1. Open the adjustable pushrod (checker) to the same length as your stock pushrods
2. Close it down two turns
3. Put your rocker rail on the head
4. Make sure you cylinder (typically #1) is at top dead center on the firing stroke so both valves would be closed
5. Put the pushrod (checker) in place on the intake valve and make sure it is in the lifter cup
6. Install the rocker and snug down the bolt (don't need to torque, just make sure it is snug)
7. Lift rocker tip up and down, if it "ticks" the pushrod is too short. If you can't easily move the rocker the pushrod is too long.
8. You can try and adjust the pushrod in place buy my fingers are too fat so I end up pulling the rocker and adjusting the pushrod length. Go either shorter or longer 1/2 turn and try again.
9. You are trying to get to the point where the lifter doesn't "tick tick" with the pushrod in place nor is the rocker snug. When you get the pushrod length such that you just barely get rid of the "tick tick", you have found "zero lash".
10. When you have found zero lash, carefully remove the rocker and pushrod without rotating the pushrod.
11. Tighten the pushrod until it is fully closed counting the turns as you go.

To figure out your pushrod length you do the following. Lets assume it took 10-1/2 turns to close the pushrod down to its shortest length after you reached zero lash. Each turn is 0.050".

Your length is then: 6.800" (fully closed length) + 10.5 X 0.050" (number of turns times the length change per turn) = pushrod length minus preload. So for this case:

6.800 +10.5 X 0.050 = 7.325"

This is the length you measured to zero lash without any lifter preload. Now lets say you want to have 0.075" lifter preload, you add that to the measured number and you end up with 7.400" pushrods.

Now repeat for the exhaust valve to verify the length. If you have something like Yella Terra's, it is the same procedure but you must snug down the rocker pair rather than the single rocker.

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cheezbrgr3

 

why do you keep replyin with cheezbrgr? 3 times this thread! You might want to edit something useful in before a mod see's it.

 

sorry i was running some tests on search indexing