Question - Adjusting the valvetrain

[GRGT1994]

I am finally to the point where I am in final assembly. Putting on the upper intake next.

Anyway, I adjusted the rocker retaining nuts a weekend or two ago. And I notice that a few of the nuts are just a little sloppy. I can turn maybe 2 or 3 on each side, maybe 1/32 to 1/8 of a turn with by bare hands. Is this anything to be concerrned about, or is this just the way they are when properly set?

Oh by the way, these are Twisted Wedge heads (part of the street heat h/c/i kit). And I am using only parts that came with the kit (pushrods, rockers, alignment plates, nuts).

 

[CManT1914]

I can't seem to find the link for the how to on adjusting rockers. But here's how you do it.

Select a cylinder to set the lash on. Turn the crank until the exhaust valve on that cylinder just begins to open, now the intake valve should be completely closed with little tension on it. Now, tighten down the fulcrum bolt as you spin the pushrod with your fingers. I have found that wiggling it up and down works too. The key is, to stop tightening the bolt when you feel either a) tension while spinning it, or b) no more up and down movement. You're at zero lash now. Tighten the bolt another 1/2 turn or so for your street setup. Then tighten down the locking nut. Now turn the crank some more until that valve you just set begins to open, and the other valve (exhaust in this case) should be completely closed. Now repeat for the exhaust valve.

There ya go man, hope this helps you out. There's a website that has a good writeup about it, I'll try to find it and post it for you.

EDIT: http://www.flowtechinduction.com/valveadjust.html

 

[GRGT1994]

locking nut, WHAT? Do the Trick Flow heads have a locking nut???

I only saw the one big nut that I screwed down onto the rockers. Did I miss something?

 

[rockin_rick]

With normal stud mount rocker arms, there is one big nut that holds 'down' the rocker arm, as it 'sits' on the valve and pushrod. That nut should have a allen setscrew in the top of it that you screw down into the stud once you've set your preload with the nut. If you don't lock these very well, they will come loose/off the stud! If you dont lock them at all, it wont take but a min or so before all of them are bouncing around with your valve springs. Be careful.

I had one come loose on me, even after I thought I had it locked down good. That is why I went with Jesel shaft mounts. More reliability, better engineering, more overtime....

Rick

 

[R.J.]

This is the best way I've found to adj rockers and set lifter preload.

With the piston at TDC with both valves in the closed position, do the following:

The first thing you want to do is verify zero valve lash. The best way to do this is to wiggle the push rod up & down as you tighten the rocker arm nut. At the point where the push rod no longer moves up & down, That is zero lash. You now have a starting point for verifying “true” zero lash & the lifter pre-load.

When you adjust the valves you are setting the lifter pre-load, Pre-load is the amount of distance the push rod seat (or “cup”) moves away from the retaining clip.

To set true zero lash & the lifter pre-load, We are going to follow the “EO / IC” procedure.

What is “EO / IC?

EO, is Exhaust Opening; IC, is Intake Closing.

We have the piston at TDC (Both valves are in the closed position), Rotate the engine in the normal direction of rotation (clockwise, if you are facing the front of the engine).
You will see the exhaust valve just starting to open, stop rotating the engine & back off the intake rocker arm.(You are going to back off the rocker arm & re-verify for true zero lash, As you are now positively on the base circle of the camshaft whereas the previous lash adjustment was just a pretty close ballpark guess.) You will once again wiggle the push rod up & down as you tighten the rocker arm nut. When all up & down movement is gone, tighten the rocker arm nut ½ turn, tighten the hex head set screw until it bottoms out on the rocker stud, tighten the rocker arm nut ¼ additional turn. You have now set the lifter pre-load at .045”.

Rotate the engine, You will see the exhaust valve fully open & then close. Watching the intake valve that you just set, You will see it open, You want to keep rotating the engine until it fully opens & then starts to close. When it is almost closed, stop rotating the engine. Set the exhaust valve the same way you did the intake valve.

Move onto the next cylinder in the firing order…

 

[CManT1914]

locking nut, WHAT? Do the Trick Flow heads have a locking nut???

I only saw the one big nut that I screwed down onto the rockers. Did I miss something?

Like Rick said, there should be an allen screw in the top of that nut you described. Once you get the big nut tightened down 1/2 turn or whatever, turn that allen nut until it tightens, then you're set.

 

[GRGT1994]

Oops. Time to break back into the engine I guess. Any chance I can get the valve covers off without removing the upper intake manifold?

 

[divit250r]

There have been quite a few posts about adjusting rockers lately, and one thing I never see anyone mention is priming the oil system to make sure the lifters are pumped up. If you change the lifters or just allow the engine to sit for a while with no oil pressure, the lifters can bleed down. If you try to adjust rockers at that point, you're WWWAAAYYYY too tight. I took the distributor shaft out of an old 302 and ran it with my cordless drill. Once all the lifters are primed, it's really easy to find "true" zero lash. Like R.J. said, without finding it correctly, it's a big PITA to adjust them. Just some food for thought.

Scott

 

[GRGT1994]

Thanks Scott. That's what the Trick Flow tech line told me too. But the guy I talked to said running the distributor would not prime the lifters. So he suggested pulling the plugs and cranking the motor with the starter for about 30 seconds. This will prime the lifters.

Should zero lash be measured with a dial caliper? Or is hand feel close enough?

 

[a50sn95]

It is not necessary to prime the engine if you are going to adjust the rocker arms. The internal spring will hold the plunger up enought to accuratley adjust them. However, you MUST be on the base of the lobe, and you must back off the rocker arm nut before you start if the engine has already been assembled, to allow the plunger to return to it's starting point.
Then, with one hand holding the pushrod between two fingers, you can spin and slightly rock the pushrod as you slowly turn down the poly-lock (the big bolt on top.) once there is no more side to side movement and it becomes difficult to spin the pushrod, you are at zero lash. I like to back it off, and re-check it a couple of times to make sure everything s seated properly. Then make one HALF turn. and lock the set screw inside the poly-lock. That's all there is to it. If you have any doubts, pull your lower off and you can watch the bottom of the pushrod.
The Goal is to get .020" to .060" preload (push the plunger down inside the lifter .020" to .060") If you have your lower off, you can rig up a dial indicator on the plunger itself and check it there. I just did this this week.
As far as spinning the oil pump drive with a drill, the guy at Trick Flow is wrong. It will prime the lifters. It will even prime the top of the engine. Again, I just did it....