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Old 12-22-2004, 06:57 PM   #1
QWKSNKE
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Rocker arm adjustment procedure

From my 'Edgar' notes.

If this a stud mount rockers this is what you do. Turn the motor slowly until you see the exhaust valve to start opening, stop, go to the intake valve tight it until there is no lash, then go 1/4 of a turn then lock the poly lock. Now turn the motor again, now you are going to see that the exhaust opens completely and then the intake starts to open, now let the intake valve open completely but as soon you see it to start closing, stop, now go to your exhaust valve do the same thing as the intake, then do all of them like that and you are set.


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Old 12-22-2004, 08:10 PM   #2
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Re: Rocker arm adjustment procedure

You wanting me to FAQ this?
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Old 12-22-2004, 08:16 PM   #3
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Re: Rocker arm adjustment procedure

not yet
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Old 12-26-2004, 11:09 PM   #4
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Re: Rocker arm adjustment procedure

Basically, make sure the pushrod is on the base-circle of the cam...not the lobe.
When the pushrod is about to push in the lifter spring (or when you cannot turn pushrod by hand anymore), you're at zero-preload on the lifter...stop and give about 1/2 turn more (or around .020"). Tighten the lock-nut & then put a little-more snug on the rocker nut again...This assures the locknut is in tension on the stud...will not back off.
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Old 12-27-2004, 09:03 AM   #5
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Re: Rocker arm adjustment procedure

Quote:
Originally Posted by coupe
Basically, make sure the pushrod is on the base-circle of the cam...not the lobe.
When the pushrod is about to push in the lifter spring (or when you cannot turn pushrod by hand anymore), you're at zero-preload on the lifter...stop and give about 1/2 turn more (or around .020"). Tighten the lock-nut & then put a little-more snug on the rocker nut again...This assures the locknut is in tension on the stud...will not back off.
Actually it's not "when you can't turn the pushrod by hand anymore" that is too tight. You tighten it up until the pushrod starts to give resistance to spinning...if it stops completely and you can't sping it then it's too tight. Then it's 3/4 turn past Zero preload
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Old 12-27-2004, 11:24 PM   #6
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Re: Rocker arm adjustment procedure

Quote:
Originally Posted by svopaul
Actually it's not "when you can't turn the pushrod by hand anymore" that is too tight. You tighten it up until the pushrod starts to give resistance to spinning...if it stops completely and you can't sping it then it's too tight. Then it's 3/4 turn past Zero preload
No, you're right. The preload really has nothing to do with how tight the pushrod "feels." because if you try your method with a new, non-pumped lifter, it will tighten freely until it bottoms out. That's why it's critical to just have the pushrod against the spring in the lifter. Then it's at zero preload...but it takes a fine-touch.

I also am leery of the 1/4 up to a full turn I hear people talk of. I've tried both & it's noisy on some rockers, quiet on others. I've found a good balance at around .020-.030 in which case you should measure the thread pitch to find true preload. Just clarifying...Good thread.
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Old 12-28-2004, 07:31 AM   #7
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Re: Rocker arm adjustment procedure

Using Edgar's method you will not be able to rotate the pushrod when everything is tightened down.
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Old 12-28-2004, 07:32 AM   #8
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Re: Rocker arm adjustment procedure

Right...once done and adjusted you should not be able to rotate any of the pushrods.
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Old 12-28-2004, 06:08 PM   #9
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Re: Rocker arm adjustment procedure

Quote:
Originally Posted by svopaul
Right...once done and adjusted you should not be able to rotate any of the pushrods.

Once the adjustments are done, you will fine some lifters a bit loose because they have not been pumped up, once the motor has been fire up and the lifters pumped up you can not turn the push rods. My motor they way I set up my rockesr is like I said, once the push rod touches the lifter and the rocker arm and the slack between the rocker arm and the pushrod is taken away then I give it 1/2 a turn. But when I want it to rev up the moon, I give it a 1/4 of a turn.


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Old 12-28-2004, 09:10 PM   #10
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Re: Rocker arm adjustment procedure

That's right. The "preload" is nothing more than a "float-cushion" for the valve as it crests the lobe of the cam. A solid will be noisy if not adjusted perfect...the hydraulic has a little leeway...a bit loser for high-revs. But there's really quite a bit of tolerance in the adjustment of hydraulic rockers...it's meant that way for even idiots to handle. That's why I feel like an idiot.
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