The smoke from the oil filler cap can tell you alot, but puffs and streams really mean nothing. LarryBible the diesel guru says that oil droplets coming out of the filler cap must be there, or the cam is not being lubricated! If it runs well, starts well, has good power, and has all of these consistently, then you can say your engine is good. People tell me my overanalyzation is bad. Little things like engine noises, blowby etc can drive you insane. If it runs good, it probably is good!