What Could Have Caused a Broken Rocker?

Found this under the valve cover on my '71 F-134 today! Anyone ever seen anything like it? What would cause this?

 

When I replace it, what can I do to prevent it from happening again - some of my valves are definitely sticking during startup.

 

If the camshaft was replaced during an engine rebuild, it could have the wrong camshaft installed.
The L4 (flathead) camshaft has higher lift on the intake valves than the F4 (overhead) camshaft.
What I see in the photo is what happens when this occurs.
It might not be right away, but after a few miles have been driven.
If you replace that intake rocker, and it happens again to any of the 4 intake rockers, I would suspect wrong camshaft.
Been there, done that.

 

My guess would be a stuck valve, I put a 225 back together after 20 years of storage and managed to bend 2 push rods before the valve started to work right.
It's been working for the last 7 years so I must have done the correct beating on it.

 

I spray PB Blaster around the valve stem and beat on the top of the valve with a rubber hammer. Beat them several times while spraying good.

 

I sprayed inside the plug holes and the OHV's this morning then beat on each intake valve stem/spring assy with a rubber hammer. #3, where the broken rocker was situated, now sits about 1/4" lower than 1,2 & 4. We have a winner! I'll keep spraying and hammering until something does or doesn't break loose. I suppose I should also pull the exhaust valve access plate and spray down there as well while I'm waiting?

 

I would pull the head...........and dis-assemble the valve train.....more than likely some bent push-rods and there is also a chance of a bent valve if the piston came up and smacked it while it was open........why guess?

 

Checked on things at lunch and the PB had broken the problem valve loose - it's moving up and down now like the other three. There's no indication it's bent. I've yet to peek under the side access plate. If it's stopped raining by 5:00 I'll do so then.

New rockers and shaft won't arrive from Walcks for a few days. In the mean time I'll think about taking the head back off and in for servicing...

I just got back from the tax office where I registered the '71 as an antique vehicle - no inspection necessary and it's good for 5 years at $10 a year! Now I just need to print up my Jeep club cards.

 

Hope all goes well for you.

 

Wiseguy...

 

I replaced the rockers and rods - former from Walcks, latter from Rock Auto. I adjusted the play and turned it over - it started right up and purred like a kitten once it got to temp, then the racket started. The tips broke off the tops of two of the rods, stuck to the balls on the rockers and were hammering the broken tips of the rods flat! It looked like the things were spin welded on without enough spin or weld. I pulled them all out and found one that was good enough to use, so I just put the 3 old ones back in that were still straight. I guess that's why they were only $1.47 each and discontinued - absolute crap!

I've taken it on several drives around the neighborhood and, apart from some stickiness on startup, it's run fine. I'll try out Seafoam on the sticking.