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2 hours ago, sdflysurf said:

Thank you for starting this thread.  So as a new aircraft/mooney owner I feel (feel as in nothing scientific here - gut telling me only) that my M20F likes to show about 5-6 on the dipstick and any more that I add has been ending up leaking/blowing/whatever out and appearing on the bottom of the plane.  Sounds like that is perfectly normal now and what exactly causes this?  My oil pressure and temp have always seemed fine, I was just getting concerned that I needed to keep a couple of qts of Aeroshell 100w+ in my baggage compartment.

I make sure to have at least 5-1/2 qts for local flying, and start trips at 6 to 6-1/2 qts. There's always one in the baggage area (or a partial quart); on ling trips I make sure to have a full one. Even in my short body, there's always room for a full quart and a partial quart.

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Sdf,

Some reasons for the oil venting overboard...

  • The case has a pressure relief vent... at the top of the case.... connected to a hose that goes out the bottom of the cowling...
  • More oil in the case... the closer it is to the vent...
  • Higher angle of attitude on the climb... the closer the oil will be to the vent...
  • The higher the MP... the more blow-by of exhaust may occur, pressuring the case...

If you fill the oil in the sump all the way to the top...

Perform a bunch of T/O and landings...

Climb out at high MP @Vx...

You may find about a quart of oil has come out the vent in a relatively short period of time...

 

don’t use this as an excuse to stop looking for leaks...

There are several, more common sources of oil leaks from seals to drain tubes that may have a drip coming out every now and then...

Many are easy to find and fix...

PP thoughts only,

Best regards...

-a-

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My oil strategy for the IO-360. 

Main mission, one hour to 45 minute flights per week with an occasional long cross-country of three hours or more.

Oil changes are completed by adding seven quarts + CAMGUARD. After engine run and inspection there is sevenish quarts of oil showing. With each subsequent flight the oil gets a little lower with evidence of oil escaping on to the belly, as well as the usual color change. When she gets put away, a small pool of oil can be traced from the drip pan to the rear of the gear door, to the breather hose before each flight.

When the dipstick lands between the four and six quart line, one quart of oil is added. At this point, there is much less evidence of oil escaping the engine but it is still flowing out of the breather hose onto the gear door/drip pan when parked. For flights greater than three hours, seven quarts go in. Upon landing, I've had between five to six quarts showing on the dipstick, while there is a good bit of oil showing up on the belly.

Oil temperature and pressures have been stable. 

Two additional quarts are carried in the baggage compartment. One quart is for when I hit the five quart line when away from home base and the other is because you never know when you will need it. During my PPL, I learned that carrying extra oil is easy and beneficial. 

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I like to run at 6 quarts.  For flights longer than 2 hours I start with 7 quarts but believe it drops to 6 very quickly.  I would love to see a level sensor that could show actual (proportional) level in 0-100% increments so you could see in real time what engine settings and conditions effect level consumption. 

Rick

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1 hour ago, Releew said:

I like to run at 6 quarts.  For flights longer than 2 hours I start with 7 quarts but believe it drops to 6 very quickly.  I would love to see a level sensor that could show actual (proportional) level in 0-100% increments so you could see in real time what engine settings and conditions effect level consumption. 

Rick

It would be easy to make a capacitive level sensor that would replace your drop stick. You could mark the electrode just like a dipstick so you could still use it as a standard dipstick. You would need a simple connector for the wire so you could unscrew it. You could probably just add a terminal to the current dip stick and use it as the electrode.

It would be interesting to see what the level would do with the engine running, oil splashing around and such.

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34 minutes ago, N201MKTurbo said:

It would be easy to make a capacitive level sensor that would replace your drop stick. You could mark the electrode just like a dipstick so you could still use it as a standard dipstick. You would need a simple connector for the wire so you could unscrew it. You could probably just add a terminal to the current dip stick and use it as the electrode.

It would be interesting to see what the level would do with the engine running, oil splashing around and such.

Probably not as interesting as this, but still mesmerizing...

 

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Add a quart at 5, no more than 6 in the crank case.

Edited by Shadrach
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Great oil flow study, Jay!

The speaker is also describing flow around corners pretty well too... and effects of speed and temperature...

And interesting note regarding safety... :)

Oil in a differential, is typically a higher viscosity, and lower temps than engine oil in an engine...

But the expectations are very similar... the oil will be spreading all over the place, leaving very little in the oil pan...

kind of explains how the first air bubbles start to show up in the oilP reading....

Best regards,

-a-

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On 5/13/2019 at 6:10 PM, carusoam said:

Sdf,

Some reasons for the oil venting overboard...

  • The case has a pressure relief vent... at the top of the case.... connected to a hose that goes out the bottom of the cowling...
  • More oil in the case... the closer it is to the vent...
  • Higher angle of attitude on the climb... the closer the oil will be to the vent...
  • The higher the MP... the more blow-by of exhaust may occur, pressuring the case...

If you fill the oil in the sump all the way to the top...

Perform a bunch of T/O and landings...

Climb out at high MP @Vx...

You may find about a quart of oil has come out the vent in a relatively short period of time...

 

don’t use this as an excuse to stop looking for leaks...

There are several, more common sources of oil leaks from seals to drain tubes that may have a drip coming out every now and then...

Many are easy to find and fix...

PP thoughts only,

Best regards...

-a-

Thanks guys - confirms all I've been wondering.  I have been told I could use an attitude adjustment so I'll check that first! ;)

I concur with the others about starting with 7 at oil change, running between 5-6 for short flights, and 6-7 for longer flights with a qt or 2 in the baggage compartment for backup.  Oil pressure and temp have been in the green and anything over 6 usually comes out.  I'm having the engine compartment cleaned and I will watch for anything besides what comes out the vent.

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11 hours ago, sdflysurf said:

Thanks guys - confirms all I've been wondering.  I have been told I could use an attitude adjustment so I'll check that first! ;)

I concur with the others about starting with 7 at oil change, running between 5-6 for short flights, and 6-7 for longer flights with a qt or 2 in the baggage compartment for backup.  Oil pressure and temp have been in the green and anything over 6 usually comes out.  I'm having the engine compartment cleaned and I will watch for anything besides what comes out the vent.

Exactly my procedure, as well.

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