On my brand new rebuilt Toyota engine. The oil had 229 miles on it and was Mobil DC 10 30. It went in almost amber clear and came out a bit darker. I did notice alot of shiney metal flakes on the bottom of the drain pan would assume this is normal for a while anyway. Also noticed some grit like large chunks of sand maybe blasting sand from the block machine work? I don't know but they told me it was well cleaned after working on it. They bored it and honed it and cleaned it was all. hummmmm or is this normal to have some sand left over? All pieces where to large to go thru the pick up screen so they probably just set on the bottom of the oil pan.
Ken
Ken