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**There have been lots of discusions on preload and zero lash setups but.....not a thread on the entire subject. Meaning its been hit or mis, it may take reading 10+ different threads to come up with an answer.**

**So here is my question...what is the total plunger travel of an OEM LS lifter ?? (from colapsed to full "pump" up)**

And here are some internet rumors I'd like to sqwash or validate.

1) and this comes from a pretty reputable guy on the "vette" forum....

"When you tighten the rocker bolt to zero lash and then torque to 22 lb-ft, I found that it takes 1/3 turn after the rocker bottoms in the stand to reach final torque. The rockers were pretty consistent with this 1/3 turn. Once the rocker bottoms in the rocker stand, there is no more preload applied to the lifter. So if you use 1 turn for zero lash to full torque, only 2/3 turn are actually applying preload (bringing the rocker down to seat in the stand). For that case I get the following:

2/3 X 1.25/25.4 X 2.7/1.7 = 0.52

When the number of turns increases to 1-1/4, you still need to subtract the 1/3 bolt turn after the rocker seats in the stand.

(1.25-0.3333) X 1.25/25.4 X 2.7/1.7 = 0.071

Note that all of these are approximate but given the pushrods are available only in increments of 0.025" any of the methods should work. What Shane recommends is using turns to figure preload and if a pushrod is the wrong length try a different length to obtain the correct range of turns on the bolt. The math allows you to estimate the new length if you don't have different lengths available and provides another tool to work with and double check your work. One other tool that a lot of guys overlook is they usually have the stock pushrods available that will provide an estimate of length when counting turns using Shane's method, but the stock length is 7.385" and not 7.400" (I and others have measured similar length of the stock pushrods) as is the internet myth."

2) Same guy on adjustable pushrod use and finding a proper preload and wipe pattern....

"Each turn of the pushrod 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 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 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."

**Would these procedures be sound advise for setting my preload on my current LS project ??**

**Thanks.....**