ORIGINAL: BBriBro
ORIGINAL: khodges
BBri Bro-- just saw this post on your Honda 4-stroke application. What a gorgeous plane! .................His reply was that they would work fine while mounted inverted, but should be stored upright for that reason (seepage past the rings).
Thanks for the compliments, as far as the engine being mounted inverted, Honda says they can be operated and stored inverted, with no limitations. The oil "tank" is round and contains the full quantity of oil, without it "puddling" in the bottom of the piston and cylinder. The only oil you would have that seeped by the rings is whatever was actually on the cylinder walls when you shut it down and stored it, (a very small amount) the actual supply of liquid oil would remain in the "tank" DId you see my pics of the piston? There are several rings, including an oil scraper, I would think it would seal quite well. Even if it didn't look at the old radial aircraft engines, they were known for oil to collect in the bottom cylinders which is why the smoked and coughed so much on startup.
It's also why you saw ground crews turning the engines through a few turns before starting them the first time each day( as well as to help prime them). They could accumulate enough oil in the combustion chamber of those bottom cylinders to cause hydraulic lock and bend rods. I reread the e-mail from Dave Carr and he was talking about oil dripping from the valve cover breather, just a matter of housekeeping rather than danger to the engine.