Hard to tell much from pics... the important thing to determine is if there has
been any loss of metal from the surfaces (pitting, spalling, scoring). If there is
no loss of metal that can be detected with a fingernail, the marks may just be
staining from some kind of chemical reaction.
If the surfaces seem smooth, do some work on the marks with green scotchbrite
or fine steel wool and WD40, and see what happens. Maybe try some fine grit wet
and dry paper with WD40... nothing coarser than 800 grit, and don't go crazy as
that stuff will remove metal from the surface, and you don't want to start changing
the shape of journals or lobes.
Cams are lubricated by running on a film of oil, so very minor surface damage
(marks that cannot be felt) does not mean that the cam is unusable.
Cheers... jondee86
PS: Might be worth measuring the journal diameters to check for wear before
investing time in cleaning them up
