My bog std 1.8 duratec in the tintop has started losing oil

I've got no obvious leaks and no obvious oily smoke either - any ideas what to check next?

Hi i made the mistake of not stripping mine when i bought it just put it strait in and it burned oil like a pig so took it out and stripped it rings wear absolutely coked oil ways blocked etc cleaned it put new rings on and honed bores now runs like a new one if there are no drips on the floor must be burning it

PCV valve stuck open?

Cheers
Stot

A cylinder leak down test would confirm piston ring or piston problems, much more definite than a compression test.