Ok so i just got my new engine broke in and i pull the valve covers to make sure the cam lobes are still good and i find a rocker arm just laying there! Then i find half of the stud and the nut laying there too. Luckily the pushrod didnt fall into the engine. I look down in there and the lifter is gone! Anyone ever have this happen to them? And how do i fix this? Please tell me the head isnt junk now!? Oh and what the hell would have caused this?

Also the rocker next to this one, on the same piston, is kinda loose. Not up and down loose like the lobe is worn off, but like side to side loose.

 

What's the lift on your cam, and what's the max lift on your valvetrain? Flat or roller?

 

What heads and cam are you running? Screw in rocker studs or press in?

 

The cam is a Comp 284h, i believe lift is .510. I have Vortec heads, valve guides machined for extra lift, and the self aligning rockers. Flat tappet cam. I believe Vortec heads are press in studs as there is not hex on the stud. There is a groove on the stud where it looks like the rocker was grinding into the stud, but it was lower on the stud than where it snapped in half. Almost like the rocker was loose and when being pushed upon by the push rod it was digging into the stud. But like i said that is not where the stud broke.

 

Any loose or "clacking" rocker arms before this happened? That puts a awful lot of strain on the rocker stud if it's slapping hard.

Also, if your rocker arm nut was only grabbing a few threads on top of the stud (studs too short, pushrods too long, etc.) you WILL eventually fatigue the top of the rocker stud, it will snap off with those few threads still inside it, the rocker arm then goes flying off and the lifter then jump out of it's bore. Personal experience on this sad chain of events, not just theory or speculation.

 

nah none of the rockers were loose before. Like I said the one next to it seems to be loose now.

So did your broken stud cause any other damage? am I able to reuse the lifter? I am going to take the head to the machine shop and have a new stud put in, and then hopefully everything else is ok. The pushrod isn't bent, and the rocker is ok.

 

you used self aligning rockers eh? are the holes for the pushrods in the heads 1/2" or larger?
you didn't use guideplates right?
what length of pushrod did you use for this flat tappet cam?
Got a picture of the carnage?

This happened to me once. Same thing. Problem was that I had elongated the slots in the heads for a bigger lift cam - the pushrods wore their own spot and got caught and snapped. Or snapped the rocker arm stud... Until I figured it out.