After about 500 miles on engine, some of the rockers came loose. What could be the cause of this.

Valvetrain:

1.6 Comp Pro Mag full rollers NSA
8019 springs from AFR on AFR 1039's w/titanium retainers
AFR guideplates
7.2 Trickflow chromeoly pushrods

Piston to Valve clearance was checked and was ok

Is there any other info you would need to possibly make any suggestions, other than just going through and resetting them all.

 

when you say came loose did the nut back off or did the rocker arm fall off the valve?

 

the nut backed off

 

Are you using the poly locks that come with Pro Mags?

 

Yes, the ones that came with the rockers.

 

As long as the top of your rocker studs are not round and the nuts/locks are installed correctly, they should never come loose.

 

If you are tightening the poly locks according to the instructions that might be your problem. I had the same problem. Once you tighten down the set screw give everything another 1/16 turn just to make sure everything is tight. works for me

 

I don't tighten the outer nut after setting the allen screw and have never had one come loose.

 

Does everyone agree that probably the main reason they came loose is that I probably just didn't lock them correctly?

 

It is surely a possibility and worth setting them again and see how it goes.

 

Well thanks for the info from everyone here. Talked to Lloyd Elliot too about the situation, he says to only go an 1/8th turn this time, and approx. 20 ft. lbs. on the locks.

 

If you over tightened them the nut may have cracked. Especially with 7/16 studs as the Comp nuts are very thin and brittle. I've broke several before and didn't feel I tightened them down all that tight, but I guess when they get up to op temp they stretch more and start to crack after a few hundred miles. As mentioned, go only 20-25ft/lbs at the most with them.
I started using ARP poly locks since just for extra POM.

 

10-12k miles on my new setup and never had one loosen up.

 

Give this guy a hand.

 

I was hoping someone would pat me on the back... I can't reach it.