When I adjusted my rockers about 2 months ago I found 1 polylock cracked...thought that it was a freak thing and replaced it. Well today my wife drives the car and said it started making a horrible noise.
Sounded like a severely loose rocker. Took the cover off and everything looked normal, but I found 3 polylocks on just the drivers side that were loose, not even finger tight. Closer inspection revealed they were all 3 cracked, 2 of them broke just backing them off.

These are Comp polys, bought about 1 year ago. I have to say, I do tighten them down pretty hard so they don't back off, but still only using a regular wrench and allen wrench, nothing with a cheater bar. Usually about as tight as I can get with the little allen wrench, and then another 1/8 turn with the hex wrench to get the proper pre-load.

With all the Comp probs lately, wouldn't surprise me if they are defective. Any suggestions on a better brand?

Here's pics of them and the rockers...I don't see anything abnormal with the rockers, and there were no marks at all on the polylocks as first thought was maybe the rockers were bottoming out on them.

 

probly made in mexico

 

 

hope this doesnt happen to mine


effin mexicans

 

I don't know about these on the car now, don't have the package for them, but I had to buy a whole set 2 months ago when I found the first cracked one...and it clearly says "American Made" with an American flag on it.

I'm just wondering if anyone else has experienced this or if something else could be causing them to break other than simply being defective. I wouldn't think these could be overtightened setting the polylock with regular hand tools and I'm not a body builder ...maybe 60ft/lbs tight or so on the lock.

 

Are those 3/8 studs?

 

No, 7/16

 

1/8 turn past tight as you can get it with the allen wrench seems a bit much. Looks like a pretty substantial groove in the stud there. The 7/16 threads kept you from stripping out,but that's a lot of metal to move once you've achieved solid contact. I know things somehow can loosen up even when you think you have them tight enough,but it appears to me you've found the limit in the other direction.

 

I torque my set screws to 45#, never had one come loose.

 

Hmm..I'm not seeing what you're seeing..where is the groove you're noticing?
Or do you mean on the tops of the studs where the polylock contacts?

Once at zero lash, I turned the lock 1/4 turn, then tightened the allen nut, then took a wrench and turned the lock another 1/8 turn.

Seems I'm the only one breaking these so obvisously I'm tightening them too much, I'll try to see what the actual tq the others are and then go back and replace all of them with the other set I have and tq them to 45# like wrd1972 did and see how that works for me....

Thanks

 

I think you've arrived at the most logical explanation for the breakage. If you were using 3/8 studs, they would be breaking as well. The stress is merely finding the weakest link in the chain.

 

There are a number of posts that recommend tightening the locks another 1/8 turn after setting the desired lash AND tightening the allen screw. This is WRONG! When you've tightened the allen screw (even with a "long arm" allen wrench) while holding the nut in place with a wrench, you have set the pre-load on the poly-lok. Additional tightening of the entire assembly WILL exceed the design fastener pre-load.

 

Yeah I thought I had read that in a number of places if why I did it that way.

I checked the ones that were still together and they were tq'd around 60-65# which is what I figured they were.
I've installed all new polys on the driver side and set them to 45#, which is about a 1/16 of a turn after just firmly snugging down the allen bolt..not tightening the allen head till I was blue in the face or anything....

So 45# about right?? I'll be doing the pass side Sunday.

 

I broke one on my car, too.

I think it was b/c i over torqued it.


I called comp and they sent me two new one's for free.

 

Just wanted to bring this back up b/c I'm running into problems now as well.

I tightened my polylocks when I built the engine similar to 2QUIK6 per recommended by several on the board and they're so tight that I snapped a few sockets getting them out and some of the rockers are coming out complete with the stud. I went 1/4 lash with my setup... first 1/8 turn then tighten the polylock down with a socket, then set the other 1/8 turn holding the wrench and turning the polylock at the same time.

This is TOO TIGHT.

Going to end up replacing my polylocks and all my rocker studs now because of this. Careful with some of the info on this board!

My simple spring swap turned into a much bigger ordeal now.