I was looking at the roller rockers tonight thinking about the procedure for setting the lash......

I've heard all this talk about spinning pushrod, moving it up and down...etc. to find zero lash. However, correct me if I'm wrong, but are you not already at zero lash when you set the rocker on top of the pushrod and valve(with lifter on base lobe of cam)???? Now the lifters are fully expanded and not down in any way(cup is at the top of spring retainer).

Seems to me all you need to do from that point is screw down the polylock until you just feel it touch the top of the rocker.....from that point go 1/2 turn and lock it down. Seems simple...am I missing something????

 

It is as simple as that. except for the fact that one can get over zelous when tightening the nut on the rocker and before you know it the lifter has been collapsed and your too tight.

 

That very thing has always been in the instructions on my Tech Page.

 

And that very thing from shoebox's tech page is what simplified adjusting the lash for me.
As he says, the poly locks spin freely and when tightening by hand they stop at 0 lash, or very close to it. This method works much better than trying to feel resistance while spinning the pushrod. Don't mess around with it too much. Spin the nut down by hand 'til it stops, adjust whatever pre-load you've decided on and move on to the next one.

 

Even though simple, it still requires the utmost care and technique.

 

ACE1252:
Spinning the pushrod by rubbing the pushrod between your thumb and index finger (a little oil on the pushrod ends and no gloves!) ~ 1/4 turn each way works very well. The pushrod will turn back and forth with virtually no resistance as you slowly tighten the nut with your other hand until the very last bit of free play is out of the system. Then the resistance will increase greatly and very noticeably and you'll be at zero lash. Try it. I think you'll find it to be very useful.

 

Just FYI... Sometimes if you are tightening the rockers past zero lash and the lifters have not been operational or are new you will feel very little resistance on some of them. This is because the lifters have either bled down or have no oil w/in them to generate any hydraulic pressure. Just stay true to finding zero lash and you will be fine.

 

Seems to me that we are just applying preload to the lifter. So why exactly does it have to be done on the base lobe of the cam?

Oh wait....if we were at max lift and preloaded it say 0.020"...when we rotate the cam back to the base circle...it's going to drop whatever the lift was and create a ton of slack.....nevermind, answered my own question. I'm fairly decent with mechanics...just never put together an engine before....

I must say that the resources on the board are excellent!!! I've learned quite a bit here!!!

 

OK here is the way i did it, when the motor was on the stand, i tightened the polylock by hand til it stopped, then went half a turn. When the motor was in the car, and running right, i removed the valve cover, started the motor, loosened the poly lock til i heard a tap, tightened by hand til it stopped, then went 3/4th of a turn. Mine are set good now. Remember Roller Rockers make a little noise, sound like a sewing machine running, thats why they make the LT4 Knock module.

 

thats almost exactly what i did but i only went about a 1/4 turn

 

I am using stock lifters, The lt1 rebuild book said 3/4th of a turn, so thats what i did, although if you dont have any tapping, i am sure 1/4th is good. You just have to get some preload on the lifter.

 

the comp rockers are only 1/4 turn right?

 

i have comp 1.52's with stock lifters and 1/4 was okay for me

 

It's the lifters, not the rockers, that dictate preload.

 

According to Comp you use .004 to .006 pre-load and however many turns used is determined by what thread count is on your rocker stud.