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Discussion Starter · #1 ·
Need some help with polylocks. I'm 99.9% sure I'm doing it right and have a theory but want to get some input.

Last November had the #6 Exhaust valve get loose and pop off the pushrod and turn a bit sideways. I figured I accidentally left it loose and didn't think another thing of it. reset that one, checked a few and off I went. I had them a bit too tight and ran through them again a couple months ago. IIRC, they are at 0.019" cold (iron block, alum heads, solid roller) but don't quote me on that - I can check at home to be sure later.

Ran about 6 or 7 passes on the car over the past 2 months and Sunday when I launched I heard some hellacious metal contact noises. Shut it down and pulled over and after a tow to the pits, I found #6 Exhaust sideways again.

Pulled the girdle off them all last night and not only was #6E loose, but #6I, one of #7 (can't recall), and #8E were all loose enough to unscrew easily by hand. On the other bank, #4E was loose as well. Took 5 turns of the allen set screw to contact the rocker stud!!! I have ZERO doubt that all of them were quite tight when I ran the valves last. Also, The flat spot on the trunion is up and the polylock fits in it. Same parts I had before and never had issues.


MY THOUGHT on why they got loose is that I noticed a decent bit of oil come out of the poly lock when I unscrewed it from the rocker stud. maybe they had too much oil in them and the set screw FELT tight, but was just hydrauliced so as some oil came out or thinned when hot, it allowed the polylock to loosen - I can see the scratches on the outside of the polylock where it had turned against the set screw for the girdle. Is that reasonable? Should I dry the rocker stud and the inside of the polylock and try again?

I'm adjusting the Exhaust when the intake is coming down almost closed and the Intake when the Exhaust is just opening. (mention that since it seems to be mostly Exhaust valves that are loose.) I back the set screwback a good bit s o there is no contact, adjust the valve, then hold the polylock while I tighten the set screw. IITRC they loosen almost a thou when tightening the screw so I set them to a tight 0.019 and then they are a loose 0.019" when the set screw is tightened. After one side is done, I put the girdle on, tighten it's set screws and lock nuts and run through the valves again to make sure they had not changed.


The odd thing is they haven't made any noise at all like they are getting loose. In fact, you can clearly hear 2 passes on video from next to the car that there is no noise. On the 3rd pass as I'm staging you start to hear occasional tick then when I come up on the T brake it is more frequent and then goes nuts as I launch. So it seems like they all got loose at one time on that pass.

Anything you spot that I am doing wrong with them?? One guy suggested maybe the roller bearing on the lifter collapsed which opened up the clearance, but that was before I found the other loose ones. Also, I compared the height of the push rod top/rocker across a couple valves and they seemed the same height so they'd all have to be broken for that to happen.
 

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You have to do your final tighten with the lock not the set screw. It takes a little bit of fiddling to get the hang of it but you get way lots more jamming torque this way.

I'll take out the play and stay on the loose dies of lash (how loose you will have to play with) then tighten the set screw down tight and then turn the setscrew and lock together till it's good and snug, maybe about 35-40 ft lbs. And recheck your lash if it's to tight you can just break em loose back the set screw up a hair and tighten them both back down. They won't come loose.
 

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Shaft rockers......problem solved!

Is the top of you studs ground perpindicular to the body "ground flat" or are sheared off and not even.

Some of cheaper studs are not flat, so when you torque the jam nut/set screw down it is not seating flush and will loosen over time.

Also, how many threads of engagement does the poly lock see? If you only have a couple it could be pulling the threads and loosening. A general rule of thumb for minimum engagment for a fastener to be successful at clamping is 1 times the diameter.

So if you have a 3/8 stud, bare minimum engagement should be 3/8 depth. On a rocker system more in this case is way better

Hope this helps
 

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I agree with Todd, also with my girdle I just barely loosen it to adj. the valves (Jomar, 2 bar design) then tighten. I could probably take the allen screws out of mine and have no issues.
 

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Discussion Starter · #5 ·
Would it be better to turn them tighter together like you said or to tighten them down (tighter than lash spec) and then back the adjuster into the setscrew. In other words, like you do when jamming two nuts together (one tighter and one looser to lock them) ??

Seems they would "lock" better turning in opposite directions, but what do I know - mine keep coming loose! :D

What about the oil I found inside - "could be" or "probably not" part of the issue?
 

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Discussion Starter · #6 ·
mrtbolt64 - I'd say I easily have 3/8 to 1/2" of thread into the adjuster. I haven't specificaly checked, but it is quite a number of turns, not just 2 or 3. I didn't see any signs of the thread pulling out or anything like that and the stud isn't sheared. I will go check them again to be certain though.

Rockers, locks, pushrods are all Comp Cams stuff. Not sure about the studs though.

I agree with Todd, also with my girdle I just barely loosen it to adj. the valves (Jomar, 2 bar design) then tighten. I could probably take the allen screws out of mine and have no issues.
Jomar girdle here as well.
 

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Set it up a thousandth or 2 loose, then snug the center lock, then thighten the entire outer nut....recheck clearance. It takes some getting used to.

Let me ask you this: What method are you using to adjust the valves?? IE, how are you making sure you are on the base circle?

FWIW, I always check mine after I snug the girdle, as sometimes you will see small changes after it is tight.
 

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Discussion Starter · #9 ·
Set it up a thousandth or 2 loose, then snug the center lock, then thighten the entire outer nut....recheck clearance. It takes some getting used to.

Let me ask you this: What method are you using to adjust the valves?? IE, how are you making sure you are on the base circle?

FWIW, I always check mine after I snug the girdle, as sometimes you will see small changes after it is tight.
I check/readjust after I snug the girdle also.

I'm adjusting the Exhaust when the intake is coming down almost closed and the Intake when the Exhaust is just opening. (mention that since it seems to be mostly Exhaust valves that are loose.) I back the set screwback a good bit s o there is no contact, adjust the valve, then hold the polylock while I tighten the set screw. IITRC they loosen almost a thou when tightening the screw so I set them to a tight 0.019 and then they are a loose 0.019" when the set screw is tightened. After one side is done, I put the girdle on, tighten it's set screws and lock nuts and run through the valves again to make sure they had not changed.
 

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You have to do your final tighten with the lock not the set screw. It takes a little bit of fiddling to get the hang of it but you get way lots more jamming torque this way.

I'll take out the play and stay on the loose dies of lash (how loose you will have to play with) then tighten the set screw down tight and then turn the setscrew and lock together till it's good and snug, maybe about 35-40 ft lbs. And recheck your lash if it's to tight you can just break em loose back the set screw up a hair and tighten them both back down. They won't come loose.
This is how I do it.
 

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Discussion Starter · #12 ·
Sounds like I just didn't have them tight enough (dammit)
Going to check the cam and lifters anyway to be sure, but it looks that way.

Now that I think about it. I know I had the set screw tight as I could get it with a T handle wrench, but I could still move the adjuster with the wrench. Obviously that means it wasn't tight enough. Just for curiosity, I'll run through a few valves and see just how loose some others got.

Still open for input, but looks like it was installer (me) error.
 

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My bad, I missed your procedure. I think they are not getting tight enough....BUT, with a girdle, once it is tightened the locks should not move/be able to back off. Strange indeed.
 

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they make a nice tool to solve these problems, although its expensive. using a t handle will not get them tight, i have had good luck so far by using my tq wrench and setting the set screws at 20 lbs. . i use to do the above mentioned way, but i decided to try something different lol.
 

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Bring that sucker out Thursday, i'll show you how its done!!
 

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A couple years ago I was running comp aluminum (red) rockers and had trouble keeping them tight. One thing I noticed about the poly locs that came with them was they didn't have the right "feel" when I'd tighten them. I bought some ARP locks and never had one loosen after that.
 

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Discussion Starter · #17 ·
For anyone interested, Videos added:

http://www.youtube.com/watch?v=PNBLOeaR4-w

The other 2 clean runs are out there too. You can hear the ticking a bit when I stage, and then the racket after I launch. Now that I listen to it and know what happened, that's just the popping back through the carb since the exhaust valve was closed. Sounded more mechanical like contact before. The launch was REAL soft too in comparison.
 

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You have to do your final tighten with the lock not the set screw. It takes a little bit of fiddling to get the hang of it but you get way lots more jamming torque this way.

I'll take out the play and stay on the loose dies of lash (how loose you will have to play with) then tighten the set screw down tight and then turn the setscrew and lock together till it's good and snug, maybe about 35-40 ft lbs. And recheck your lash if it's to tight you can just break em loose back the set screw up a hair and tighten them both back down. They won't come loose.

YUP.
I used to have the same problem and I was doing it like you do...then I went to this method and they don't move.
 
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