Pitting on contact surface of valve adjustment screws

[rcx132]

Have you ever seen anything like this before? A few of the valve adjusting screws on a 1990's cylinder head have strange pitting on the ends. One has a chunk chipped off.

 

[Guineafowl]

Case hardening breaking down?

 

[Ubique]

Probably just low quality in the first place exacerbated by work hardening, we see pitting on followers & valve stems (actually chips missing) on the rare occasion we have something of that era in, occasionally newer stuff as well.

 

[Keithmac]

Used to be quite common on Yamaha SR125's for the valve to wear down due to poor case hardening.

Kawasaki had their "chocolate cams" I did a valve service on one and the cam lobes were a real mess!, new cams and followers on that one.

Once you are through the hardening it will self machine itself.

 

[Trevorleach]

Lots of trucks do the same, some even have the lobes rotate on the camshaft, which is mainly a volvo thing.

 

[Ubique]

Fords do it too...