[QUOTE=lifeofreilly57;1601767]. Seeing chrome specs in the oil filter
folds usually means there's a crank rebuild
in your future.
I don't think Perkins
chrome plated their crank journals. So if you see chrome flakes in the filter it might be a piston ring coating.
Bronze is usually a bushing. Steel parts
are gears or perhaps a lifter or valve train. Iron parts
are often a cam lobe. Aluminum
(piston) and bearing material often look the same. You can tell the difference with a soldering iron tip. The tin coating on the bearing will melt. Copper is a worn bearing. What you see most often are rust flakes and bits of carbon. There is sometimes what we call "mung" which is kind of a mud from the cylinder walls and everything else in there.