LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Engine Ticks at High RPM?

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Old 06-09-2009, 02:43 PM
  #16  
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Originally Posted by Hal Fisher
The problem turned out to be the #5 intake rocker somehow loosened and popped off the valve head. Only the side of the rocker was pushing the valve down. I know I tightened the lock allen screw. If it does it again (and doesn't destroy the engine in the process) I'm switching to hardened pushrods and guides, and some new rockers. Oh, and I also shot some air down the pushrod. On startup everything was fine and I pushed the revs over 5k and check the rocker one last time before I buttoned it up. Crossing my fingers...

Hal
Are you saying the rocker was opening the valve by depressing the retainer, not the valve stem tip?

If that's the case, you're really lucky, because that can cause the locks to pop out and drop the valve.

I wonder if that's why CompCams recommends NON self-aligning rockers/guide plates and hardened rods in performance applications.

Jake

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Old 06-09-2009, 02:53 PM
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Originally Posted by JAKEJR
Are you saying the rocker was opening the valve by depressing the retainer, not the valve stem tip?

If that's the case, you're really lucky, because that can cause the locks to pop out and drop the valve.

I wonder if that's why CompCams recommends NON self-aligning rockers/guide plates and hardened rods in performance applications.

Jake

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Sorry, what I meant to write was the rocker side was pushing the valve STEM down. Yeah, I don't know if I like this SA set up anymore.

The lock allen never did make that much sense to me. I guess it's super important that you tighten the lock allen while holding the outside nut in place so they don't turn together that last little bit. That way the locknut is actually using a binding action that may provide a real lock.

Hal

Last edited by Hal Fisher; 06-09-2009 at 02:58 PM.
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Old 06-09-2009, 03:08 PM
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Originally Posted by Hal Fisher
Sorry, what I meant to write was the rocker side was pushing the valve STEM down. Yeah, I don't know if I like this SA set up anymore.

The lock allen never did make that much sense to me. I guess it's super important that you tighten the lock allen while holding the outside nut in place so they don't turn together that last little bit. That way the locknut is actually using a binding action that may provide a real lock.

Hal
The technique I use involves setting the preload, tightening the allen lock screw and then turn the whole lock-nut set-screw assembly about a 16th of a turn. That jams everything together and has held for quite a while now. I think simply tightening the lock screw down doesn't provide enough 'force' on the union...

I'm glad to see it was something as simple as a loose rocker.
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Old 06-09-2009, 03:13 PM
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Originally Posted by bw_hunter
The technique I use involves setting the preload, tightening the allen lock screw and then turn the whole lock-nut set-screw assembly about a 16th of a turn. That jams everything together and has held for quite a while now. I think simply tightening the lock screw down doesn't provide enough 'force' on the union...

I'm glad to see it was something as simple as a loose rocker.
I need to make sure this is done right. I'll go back out and do it that way. I certainly don't want to ruin my engine because I was being lazy. Crane just recommends you hold the nut while you tighten the set allen.

page 2, step 4
http://69.20.53.62/pdf/425e.pdf

Hal
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Old 06-09-2009, 03:21 PM
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Originally Posted by Hal Fisher
I need to make sure this is done right. I'll go back out and do it that way. I certainly don't want to ruin my engine because I was being lazy. Crane just recommends you hold the nut while you tighten the set allen.

page 2, step 4
http://69.20.53.62/pdf/425e.pdf

Hal
Yes, they do..... as does Comp Cams. I was just not comfortable that the tiny amount of force applied could actually hold that polylock together. Some guys actually find zero lash, screw the set screw in and tighten them the 1/2-turn together. That seems like asking for trouble to me....

Anyway, a little turn with both the polylock and the set screw won't hurt anything...even if it doesn't help....chuckle.
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Old 06-09-2009, 03:57 PM
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Originally Posted by bw_hunter
The technique I use involves setting the preload, tightening the allen lock screw and then turn the whole lock-nut set-screw assembly about a 16th of a turn. That jams everything together and has held for quite a while now. I think simply tightening the lock screw down doesn't provide enough 'force' on the union...
Yep, I agree and that's exactly how I do it too.

Jake

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Old 06-09-2009, 06:17 PM
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Originally Posted by bw_hunter
The technique I use involves setting the preload, tightening the allen lock screw and then turn the whole lock-nut set-screw assembly about a 16th of a turn. That jams everything together and has held for quite a while now. I think simply tightening the lock screw down doesn't provide enough 'force' on the union...

I'm glad to see it was something as simple as a loose rocker.
+2 on this method
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