Bought a 455 off Craigslist and this is what I found. Can any one tell me what may have caused this ?

 

Something very bad. I had a push rod bend and break, along with the guide plate. The Scorpion rocker is still useable. Yikes.

 

Too much press-fit on the pushrod socket?

What was the lift, and which valve springs were used? Interference with valve guide/valve stem seal and retainer?

 

I haven't removed heads yet but nothing looks unusual topside.

 

Rotate engine and see if rocker body is hitting the polyloc at full lift.

 

Looks like your thread got hijacked by a different rocker set. Rick when you bought the engine from the ad, did the seller say who built the engine?

 

Post pics of the bottom side of that rocker. Check for valve spring coil bind and/or inadequate retainer to valve guide/valve stem seal clearance.

 

IMO, not enough clearance between the bottom of the rocker and the mounting stud, let s see pic of the bottom of the rocker.

 

He only said he had it built by a guy down in Florida a couple years back.

 

Bottom side of rocker.

 

What's the valve tip look like? Narrow, pattern, centered in the stem is good. If the rocker roller fell off the stem, you got problems.

 

It does not look like any binding on the stud. Maybe a defective rocker? Strange on such a clean break.

 

Could just be Scorpion junk, too

 

Not a fan? They are US made and I thought they also make rockers for companies like Harland Sharp. Maybe the owner is FOS, thought he claimed they made most of the name brand rockers. I seriously had a pushrod bend and break, the rocker is still useable.

 

I don't know. Are they all cast? I thought the better ones were billet. Of course, I have no room to talk with my Mondildo purple HS wannabes,!!! 🤪

 

Harland Sharp are billet and are made in house dating back to the 1960s; they also were making some of the purple rockers for Mondello years ago when Joe was still around.

 

Well, only a decade old thread...

First, none of these are cast or "billet". They are machined from an extrusion.
Second, the marks on the valve end of the rocker sure look like it was hitting something and binding up, which would explain the fracture.

 

Hmm so if lifter was stuck roller tip was not in position! Nah Joe I think maybe damaged happened as pushrod was bending to get damage on tip by roller. Jmo

 

That's comforting. I bought them when Joe was around, but Lynn Pullmyfinger was doing sales. They were advertised as Harland Sharp's, but came in a plain white box with a sticker over the original part number sticker.... What else would you think other than marked up, Ding How garbage?

 

That is good, the guy from Scorpion was probably FOS. Yeah, my next set will be Harland sharp. Scorpion do have two levels of strength, pretty sure mine and probably this one is the lower level.

 

The roller on the tip doesn't seem to have much clearance.

 

All the above and coil bind too

 

I agree.