250 Chevy, rocker arm nuts backing off. - Inliners International Bulletin Board

I'm having trouble keeping my rocker arm nuts adjusted tightly. They tend to back off and cause the rockers to chatter. I've just rebuilt the engine, I didn't replace the nuts. Should I have replaced them? Is there a preferred type?
Is a locking nut used or recommended? Can I put a thin nut on top of the rocker nut and tighten it against the nut as a way of locking it in place?
Any Ideas?
Thanks.

If the nuts spin on the threads pretty easy,then you should have replaed them.

You can put a thin jam nut also.

You can also buy aftermarket rocker arm nuts that are called polly locks,they have a center allen keyed set screw.
http://www.speedwaymotors.com/Poly-Locks,3238.html

Rick

Have you checked any local parts stores (Autozone, Advance Auto, etc)? You can get a kit for about $3.00 that includes a new rocker, pivot washer, and nut. That might help ya. Just an idea.

-Ted

HAPPY NEW YEAR!!

You said that the rockers are loosening up after a fresh rebuild. How far are you screwing the adjusting nut down when you adjust the valves, and are the lifters solid or hydraulic?
If you're running hydraulic lifters, the adjustment is one full turn after the rocker stops making noise when you're tightening the nut with the engine running. With solids, there should be an adjustment that you set with a feeler gauge. If you're doing all that and the rocker nuts are still loosening up, refer to the posts above. I can recommend the poly locks. I've used them before and they work very well, but are pricier than the rocker kits at Auto Zone and other parts stores.

Thanks to all three of you. I'll look into your ideas tomorrow.
I much appreciate it!
Bill
Inliner #1783

Check and make sure the studs are not pulling out of the head, this can act just like nuts coming loose. Lay a straight edge across the top of all 12 studs to check them. joe

X2 on what Joe H said.

FWIW I like polylocks, set them once and they don't moove (till you want them to).

Thanks fella's.
I'm ordering some polly locks.
Bill II #1783

You are not alone. My 250 had that problem just a few weeks ago.
I guess it aint like a flange that just holds two things together. The constant pushing and rocker arm motion is bound to stretch the threads over time. Maybe we cant see it with the human eye, we only hear the clatter. ha ha