AFR 195 heads, comp cams magnum roller rockers. every 1,000 miles or so the #3 exhaust rocker keeps coming loose, none of the other ones do just this one. The adjustment procedure i use is as follows.... cam lobe 180* off of lifter, finger tighten hex nut while twisting pushrod until resistance is felt, tighten hex nut 3/8 turn, tighten down the allen head lock, 1/8 more turn on the hex nut for a full 1/2 turn after resistance is felt on the pushrod.

It also seems as though the the allen head lock is digging into the rocker stud and has created itself a groove, i am unsure if this is normal or not, and i did not remove any of the other locks to confirm if they are like this as well, it also seems that this same lock has a hairline crack in it, but once again i am unsure about it. I have attached some pictures, maybe someone can help me, the first picture is how i found it after hearing it ticking and removing the valve cover, the third picture shows what looks to be the hairline crack.

 

The set/lock screw should be the last thing you tighten. Don't move the hex nut after the lock screw is set. That defeats the purpose of the lock screw.

If you believe there is a crack in a nut, try a different nut/lock screw assembly. You could assemble the suspect nut and lock on a bare stud, then observe the suspected crack area to see if it has opened under the pressure of the lock.

 

Had one just like that (no crack though). If it's cracked, replace it for sure. What I did on the stubborn one that loosened was used some Blue Loc-Tite, ( was told not to use the red stuff) and my problem has been solved for close to 5,000 mi. now...

 

thanks for the replies guys. i talked to a rep at comp cams about this, and he is going to send me a poly lock and set screw under warranty even though i bought them 2 years ago. he said that the way im tightening them down is the proper way to do it and that is the way they recommened to customers how to do it. the reason being is because you can't fully tighten down the set screw and by turning the last bit on the rocker nut you are "wedging" the lock onto the stud. i also did some searching on the forums and on google, seems like a lot of people are doing it this way without problems.

i would like to be able to tighten the set screw as the last part of the process, but you just can't get it tight enough. I probably just over tightened this one the first time i put it on and then it cracked, so i will be cautious when putting the new one on so i don't over tighten it, and hope that it solves my problem. should be here on monday, and in a 1,000 miles or so i can give an update if it worked or not.

 

I would remove the rocker stud and dress the top of it. (file, grinder) Then reinstall the rocker stud with the new poly lock. That way the new lock set screw has a fresh rocker stud tip to bite into.

 

If it is not a roller cam you may have a lobe going flat.

 

its a roller cam, i got the new poly lock set installed and its fine now, but we will see after some use. thanks for the help guys.

 

i ahve used a similar tightening technique. first i tighten the hex nut,then tighten the allen set screw, then turn both at once for last bit. This locks it REAL TIGHT! you cant get it that tight with the allen wrench alone. Mine never loosen, not once in 20 years using this method.