PLRX

I'm frustrated with the adjustment of these roller rockers. I have followed all info, advice, videos and instructions pertaining the adjustment and the "clacking" continues.

I did the zero lash and 1/8 turn...clack
I did the zero lash and 1/2 turn, quieter but some clacking.

Are these things mean to make noise or are they supposed to be "quiet"

The engine, LT4 starts, no engine light but the clacking bothers me. Am I wrong?

I already have enough noise with the roller chain...that's another topic

JAKE

Roller rockers trunnions (the part that slides down over the stud) have to different sides. One's rounded and one's flat. The flat side must go UP.

Also, in order to find TRUE zero lash, the lifter has to be on the base circle of the camshaft lobe. If the lifter is on the cam lobe's ramp, the preload setting will be wrong.

I always recommend setting lifter preload by using the EO/IC method. The procedure should be posted in the Tech Tips section on this Forum.

If you need me to, I can post it again here.

Jake

West Point ROCKS!

bigwave71

try it this way http://paceperformance.com/index.asp...=Custom&ID=637

JAKE

Yep, that's how to do it. Just be sure you correctly identify the intake and the exhaust. Remember, front to back, EIIEEIIE:

E=EXHAUST
I=Intake

Jake

West Point ROCKS!

PLRX

Got it, I'll try these again. This are the same instructions from Crane Cams at You Tube.

Once this is finished, are the rocker supposed to be tight or slightly loose?




Valve Adjustment Procedure
1. Valves can be set on a hot or cold engine. A cold engine is a lot more comfortable to work on. Major camshaft manufacturers recommend setting valves cold, to avoid erroneous adjustments on lifters that may be "pumped up" If you are setting valves on a fresh engine that has not been run, everything should be well lubricated before you begin.

2. Remove both valve covers and remove the spark plugs to make the engine easier to turn over. Also, If you are setting valves on all cylinders, it is generally easier and less confusing to just loosen all of the rocker arm adjustment nuts before you begin. This also allows for all of the internal lifter plungers to return to their "home" position.

3. Using a long handled ratchet or breaker bar attached to the crank bolt, turn the engine over in the clockwise direction.

A. Starting with #1 cylinder, turn the engine over until the exhaust pushrod just begins to move up.

B. At this point, stop and adjust the intake valve on the same cylinder.

1) Tighten the rocker until you can roll the pushrod between your thumb and forefinger with the slightest bit of resistance.

2) At this point tighten between an additional quarter to half of a turn.

C. You have now adjusted the #1 intake valve. You will now want to turn the engine over while watching the same intake pushrod that you just set, it will go full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. By following this procedure, you are assured that both of the lifters are at the base circle of the cam and that there is no additional pre-load applied to them from cam lift at this point.

D. You are now able to repeat this procedure on the remaining cylinders.

4.Re-install your valve covers and your valve adjustment procedure is finished

JAKE

When the preload is correctly set AND with the lifter on the base circle of the cam's lobe, you can still wiggle the rocker arm.

However, if the valve has started to open or is already open, you shouldn't be able to, not without using significant force.

Be sure the underside of the rocker arm isn't touching the valve spring retainer. This clearance issue is sometimes the source of noise.

If yours are touching, the underside of the rocker arm should show witness marks. Or, you can get down really close, with a flashlight, and see if you have about .060" clearance between the underside of the rocker and the valve spring retainer.

Jake

West Point ROCKS!

toptechx6

Do you have the factory roller rockers or aftermarket? The LT4 factory rollers are set to a torque spec, not adjusted like aftermarket types.

Firevette

Thats how I have always done it.

383vett

I am using the Crane Cam gold rockers on my L98. They require 1 1/2 turns after zero lash compared to the stock 1/2 lash. Make sure your instructions specify what amout to adjust the rockers and follow suit.

STL94LT1

Midnight 85

I've got the same problem with mine. I have the Crane Energizers and I do the lash procedure just as stated here except I set the ex. just as the int. starts to close, not when it's almost totally closed. This might be my problem so I will give this way a try. I have never heard of more than 1/4 to 1/2 turn after zero lash but I am going to check with Crane just to be sure.

JAKE

Remember, what you're setting is lifter preload. You only adjust the rocker arm nut in order to set the lifter preload. The nut's used to establish the preload you want.

Ideally you want the lifter plunger to depress .030" (+/- .010").

However, there are certain types of lifters, like CompCams Pro Magnums, "R"s which only call for a preload of .002" which translates into a turn of ONLY ONE FLAT of the rocker nut, but I was assuming you were running lifters OTHER than those.

So with the exception of those "special lifters" in order to establish the .030" of preload, turning the rocker arm adjusting nut 1/2 turn from ZERO lash puts it at .030", give or take a tad.

Remember, too, that the lifter HAS to be on the base circle of the camshaft lobe when setting the preload.

Jake

West Point ROCKS!

coupeguy2001

Normally, running, you turn the rocker adjusting nut 1/4 turn after it stops clacking, then turn it another 1/4 turn to get 1/2 to 3/4 turn to set the lifter plunger right in the middle of the lifter bore. I do not recomment turning it more than 1/4 turn at a time, since you are letting the valve hang open whe you are turning the nut with the engine running.

One turn is enough from the factory. Been that way forever since 1955.
Although, if you are working with aluminum heads, they "grow" with heat. I would recommend that you adjust them hot, and clean up the mess later.
Be sure to keep a fire extinguisher handy in case. Oil does burn.
Anyway, if you have adjusted them, and they still clack, remove a couple of them, and make sure that they aren't hitting the springs when they move. If they need to be clearanced, get another type of springs or rockers

ArmyBoyATC

In my expierince roller rockers make more noise than regular ones but it isnt a loud clack noise jus a small tick.

toptechx6

The LT4 factory roller rockers are different from aftermarket types. From the 96 FSM, please note the difference between LT4 and LT1.
Once zero lash is found tighten LT4 adjustment nut to 18 ft. lbs.

DVNCI

I adjust mine while running as well. Though I had warnings of oil going everywhere, don't think I got a drop outside of the heads.

Just go real slow, make sure not to drop anything!

I figure doing it while running is the only way to truly get it dead nuts since you are adjusting for a running, hot, condition. I'm not a motor guy by any stretch, but it worked great for me.

LD85

RU, how many turns, 1/4 etc when adjusting them hot?

engle1147

If you're sure you got them all set the correctly the first time (between 1/8 to 1/2 turns of preload) just pull the valve covers and tighten or loosen them all in 1/4 turn increments and see if the noise goes away with different levels of preload. If not....return them to where they were set before.

BrianCunningham

The LT4's had a recall on the rockers

http://www.hashmarks.com/techtips/rockerarmrecall.htm

PLRX

I've never tried to tighten them to 18 lb torque.
I was told not to follow this procedure because I had the heads worked, different cam, springs and valves. Would that work?

Next weekend, I'll be doing it, I think the best method in here is by coupeguy and to adjust them while the en gine is running. I'll get lots of rags, the extinguiser to get it done.

This is the only thing holding me back to get this baby on the ground.