Oil Usage Lycoming O-360

[Kent Ashton]

Originally Posted by Mandolin!

Hi Kent what does that indicate when the cylinders are polished and oil is pooling? I have a RV7. IO360 about 100 hrs on the engine good compression and also burns 1/2 qt every 2 hrs. Dan

PM'd you. I have seen them get polished from rusting: the cylinder sits, develops rust on the walls from moisture and from acidy oil, Each startup scrapes off some of the abrasive rust and reduces the hone pattern. Eventually the walls get polished and rings skate over the oil film allowing it to burn in the cylinders. It wouldn't be such a big deal except the excess oil reduces your detonation margin.

Have you ever blown air through your engine after shutdown and watched moisture come out of the breather? It's amazing how much moisture remains. Call me anal but use a small air-mattress inflator and blow the moisture out and run a homemade dehydrator when I'm not going to fly for a while.

[lr172]

Originally Posted by Mandolin!

Hi Kent what does that indicate when the cylinders are polished and oil is pooling? I have a RV7. IO360 about 100 hrs on the engine good compression and also burns 1/2 qt every 2 hrs. Dan

Walls are glazed or your oil control ring lost it's temper are the most common. I had one cylinder glaze during break in and left oil fouled plugs and pooled oil. It is not too much work or cost to pull the cylinders, run a quick hone through them and install with new rings. I spent more time pulling the baffling than anything.

Larry