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Another lifter preload, zero lash , t&d rocker question...

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noahzark

Member
Joined
Feb 13, 2007
Messages
340
...i have stock ported heads , bought a hydraulic cam kit with springs, cam ,lifters , pushrods....i have t&d 1.55 roller rockers...my pushrods are 8.220...is it as simple as turn the pushrod while tightening rocker then at end plus half a turn???...yes 1 is at tdc etc....how do i know i have the right length pushrods....thanks for help...after you tell me ill tell you in the engine build post...lol...thanks noah.
 
Use care......

Most roller rockers have small oil passages drilled in them, to oil the p rod seats.
If you screw the adjuster out too far, you will block the passage, and the ends of the rods will be toasted.
Suggest you follow the mfgrs instructions. Usually, they want a minimal number of threads showing under the rocker body.
 
T&D's have quite a bit of room for adjustment before the oil hole is blocked but you still have to be careful not to go too far...I can't remember how far they can be adjusted...I think if you bottom out the adjustment screw and then backoff a full turn that was the max it could go without blocking the oil hole...not positive on that so best to call T&D...each full turn of the adjustment screw is .050...you want a preload in the .030-.040 range...on mine I find zero lash...basically find the point where the pushrod stops moving up/down...then go another 3/4 turn...
 
It depends on the lifters used, at least one type of lifter calls for almost no preload.

To be sure if you have the right pushrods (PR's) - adjust the valves and then see if the adjustment screw (AS) is in the proper location.

Lifter must be on the base of the lobe, then turn the AS until it takes all the lash out of the PR - it is very easy to tell when this happens as you will have one hand on the PR as the other moves the AS back and forth just at the moment of contact.

If you have the usual lifters, 1/2 to 1 turn after zero is what is common.

If you look at the rocker arm you will see a hole in the threads where the AS goes. You will also see a spots in the AS where the oil goes from the PR seat to the hole in the AS threads in the rocker arm. You will see what the other posters are talking about with regard to proper position of the AS in the rocker arm. With shaft mounted rockers, the determining factor in PR size will be that AS.

Do the same with every lifter. There is a procedure that lets ya get several lifters at a time but I like to watch each cylinder go until I am certain the lifters are on the base (valves closed)

Make sure the lifters have clearence where they go thru the heads - touch nothing but the lifter cup and the AS cup.
 
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