It is the same one and it has happened 3 times. All three times I have either heard it or seen the knocks increase on my data scanner and taken the car off the road. I bought the pro mags, polylocks and arp studs all used form the same guy who said he had no problems. When I installed it I put in new springs and new gm lifters. Everything was fine for about 200 miles, then it backed off the first time. I have taken it apart and inspected everything and here is what I saw. The top of the stud had a small groove cut into it from where the bottom of the polylock set screw made contact with it. The set screw was slightly worn down in the same area. The polylock was not cracked, and the pushrod was straight. The rocker looked fine as well. I called comp cams and they said it could possibly be a stretched polylock or stud, the groove in the stud, the guideplate not aligned correctly (only one side?) or a problem with the lifter. They said I could try and file down the stud slightly to get rid of the groove but I have not done that yet.

All had 1/2 turn preload and I tightened the polylock first, then set screw then 1/8 turn together.

1.Would a dremel and a sanding barrel be able to sand down chromemoly?
2. Suggestions or previous experiences?

Thanks in advance!

 

Replace the stud. JMHO

 

Replace the polylock and the stud.

 

I was thinking about switching the polylock to another stud and see which part the problem followed then replace that. So do you guys think one of them is stretched?

 

Ditto on replacing the stud and the p lock.

 

feenix88:
If the set screw had lost it's edge, how about going to the Lowes or Home Depot (or local industrial supply) and get a new set screw. If you continue tightening the set screw then cranking another 1/8 turn on the lock and screw together you eventually will crack the poy-lock body. Others here have done just that. You might try using a long-arm allen wrench on the set screw if you're not already using one.