Snaken, do you run any air filters on your trumpets? If so could you post a pic for me please. As far as the non return valve from the catch can, I've got the same setup as Philm with a gate valve flush with the bottom of the chassis that can be turned on and off to drain the
oil from the catch can. I would have preferred to return the line to the sump but had no provision on the sump. I hope it meets regs when the time comes for rego inspection.
Regards.