Exhaust valves

[ashills]

hi there need some help
the guy rebuilding my engine has looked at the exhaust valves and says that they have a black coating on them (almost like a chrome??)
and on the back of the valve heads its started to brake up a little ?
anyone shed some light on what it is or if it should be on there

 

[zia]

carbon?

zia

 

[jasegould]

clean them on a wire wheel then look for cracks etc

 

[Fast Guy]

cooked on oil? (ie carbon by now I expect)
Unless it's some sort of thermal coating.

 

[Nad]

Ever seen the Optimax advert. The build up on the back of the valves is exactly what it is meant to get rid of.

Nad