Originally Posted by Rusty

All the vanes on the impeller are in the air flow. No part of the impeller touches oil. The oil is in the middle housing. Think what is happening is a combination of things. Oil level, high rpm, fluid expansion, poor venting. The oil capacity of the housing isn't that much. With high rpms, the oil gets splashed around a lot. Also with the high rpms, you heat which makes the oil expanses. And then you have a pipe plug with a simple hole drilled into it. One thing to do. You need to do is make a shield on the bottom of the vent plug to keep oil away from it. And put some type of breather on top of it. Also what you could do. Put a hose fitting where the vent plug goes. A length of hose. Then you need an orifice of some type in the hose. Then put the end of the hose into a catch can.

When I worked for ElliottTurboMachinery. I built and repair stuff like this.