Extra Oil Blown Out

[AlanA]

It seems to be a common experience that anything over 6 to 6.5 quarts of oil in the M20J gets blown out.  My question is, does most of the oil get blown out during runup, takeoff and in the first few minutes or more or less gradually until it gets down  to that 6 quart mark?

[rgpilot]

My experience is that anytime you run at higher RPM's use blow out more oil. Cruise at 2500 RPM blows out more oil than 2400. Takeoff at full RPM is going to blow out the most oil.

[MooneyBob]

Where exactly the oil get blown out from? My J is new to me and I had 7 3/4 qt oil in it before I put 4 hours on it mostly in the pattern. I didn't notice any oil on the belly or anywhere else. Where should I look for it?

[The-sky-captain]

MooneyBob- our Lycomings will spit generally everything out over 6 quarts. Try leveling off at 6 qts and see how your consumption is

[Lood]

Where exactly the oil get blown out from? My J is new to me and I had 7 3/4 qt oil in it before I put 4 hours on it mostly in the pattern. I didn't notice any oil on the belly or anywhere else. Where should I look for it?

 

If there's no oil on the belly and the level keeps falling, then it's not blowing it out, but using/burning it.

Look just behind the breather at the bottom of the cowling, to the rear of the cowl flap.

[Piloto]

Look behind the tail pipe on the belly. On a  good running engine the exhaust stain should be yellowish to white color. If the stain appears dark brown the engine is running to rich. If the stain appears dark and oily at the touch then the engine is burning oil. First thing to look when assesing engine condition. Also remove bottom spark plugs and check for oil on them. This will help you in finding the culprit cylinder. If all of them appear wet suspect poor crankcase breather ventilation. Check that the breather hose has no kinks or holes. Crankcase breather pressure can force oil into the combustion chamber through the piston rings. 

 

José

[MooneyBob]

Thank you guys for all these advises. It has really big value for us new Mooney and plane owners.

Question: Let's say the oil consumption has stabilized and it is about 1qt / 10hrs. You are preparing for 4 hours flight. How much oil would you add? What would be oil level before takeoff considering the time of flight and maybe some reserve?

[larryb]

I will add a quart before a long flight, bring it up to 7.

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[AlanA]

I always bring up the oil to 7 qt before a long flight.  I know some of it going to get blown out but I like the idea of having a bit of fresh oil in the sump.  I think of it like a mini oil change.  I don't know if it makes the engine feel better but it makes me feel better.

[Bob - S50]

Thank you guys for all these advises. It has really big value for us new Mooney and plane owners.

Question: Let's say the oil consumption has stabilized and it is about 1qt / 10hrs. You are preparing for 4 hours flight. How much oil would you add? What would be oil level before takeoff considering the time of flight and maybe some reserve?

Personally I wouldn't add any.  At that rate you'll burn less than half a quart.  We always wait until we get down to 5 quarts and then add a quart to bring it back up to 6.  If I wanted to be extra conservative, and the current level was below 5.5, I could add some to bring it up to 6 before I left.  If we put 7 quarts in it will be gone in short order and start burning into the 6 quarts anyway.  Just my opinion.

 

Bob