Inliners International Forums General Discussion Engines Rocker problem?

I broke a rocker. It's a stamped stock rocker. It broke at the pivot point.

What do you think caused this?

The remaining rockers appear to be fine. It happenned during acceleration (sub 3000 rpm's.) 9000 miles since head was installed and 8000 miles since valves were adjusted.

Looking for any input and thanks.

They don't last forever, especially if the ball runs dry, which tends to lock the rocker body to the ball.
Is the interior of the ball recess blue/purple/yellow? Scuffed?
Might just be a bad luck fatigue crack.

How big is the cam. That was a problem with the BBC's when you got over .500 lift with the stock rockers. They offered a long slot rocker to correct that, but it was still stamped. Pull a couple of other rockers off and look at the slot where it fits over the stud and see if any are showing signs of rubbing the rocker stud, should be shiny if it is. Not sure how much the stock rocker can take as far as lift or spring pressure(hyd. or solid lift), there different even if they are the same lift.

I pulled apart 3 more and 2 of them are very a light shade of blue and those two are scuffed. The one that broke is scuffed more.
None of the ones I pulled apart show any signs of contacting the studs.
All of the pushrod tips and valve stems look very good. Are the balls supposed to rotate in the rockers? Because it's obvious that none of them are.

Lift is a little less than .474 (Comp Cam 61-232-4 cam) I put in the valve springs recommended for the cam and I'm no where near coil bind.

The rockers and balls were used when I put them in. Maybe I should pickup a new set or do you think something else is going on?

I have another set of used ones at home, but unfortunately that is 60 miles from where I work (that's where I am.) Tomorrow is another day.

Let me know what you think.

The stock ones should work fine.

I have also broken stock rockers. Pushed a pushrod right through one. Replaced that one and all was well.

Does it look like sufficient oil is getting up top to lube them?

If you really want to stay with stamped rockers, then get all new ones. I now prefer good roller rockers.

I assume they are getting enough oil based on that when I removed the valve cover all of the rocker were filled with oil.

But, after getting home and looking over my other set that I have I noticed the two sets of rockers are a little different. I have two sets, one set is from a '67 and the other is from a 71 off from a Nova; the Nova head is the head that I installed the lumps and positive valve seals into. I used the 71 rockers due to they are what were on the head originally. The ones from the 67 do appear to be heavier.

I'm defintiely going to purchase a new set no matter what.

Has anyone used the Comp Cams stamped rockers (part #1261)? They are listed as 1.75 ratio instead of the stock 1.7, will that cause any issues in terms of clearance and/or pushrod length?

Stock ratio is 1.75.