M20 Oil Separator Survey

[dfgreene61]

In your opinion, the M20 Oil Separator is:

 

1) The greatest thing since sliced bread.

2) Basically useless.

3) Potentially causes harm.

 

I've had one on three of the planes I've owned, and none of them would let you "fill" up the sump.  They spit up oil regardless.

 

My vote - 3

 

 

[BigTex]

My plane has one... That being said, I am concerned that it might potentially do some damage. As the great Mike Busch said about these devices... It's like taking a hose from you mouth to your butt.

[Hank]

Why are you trying to "fill the sump"? I've not heard of any Mooney that will keep more than 6½ quarts [out of 8] in the sump. I certainly don't try.

[Piloto]

I have the M20 oil separator and could not be happier with it. I fill to 8qts and get about 8-10 hours per quart (IO-360) on one hour flights. Absolutely no oil on the belly. The trick for good performace is on the installation.

 

1. Make sure the M20 inlet is at least one inch above the crankcase.

2. Mine drains to the bottom of the valve cover.

3. Make sure that the breather hose/tubing has no holes. Some mechanics drill holes on the tubing thinking about icing. But the reality is that you do not need them due to the engine temperatures. Any hole will impair the suctioning effect of the oil into the M20.

4. The breather outlet tube should extend beyond the cowl flap for better suctioning

 

The oil accumulated in the M20 will not return to the engine until shutdown due to crankcase pressure when running. It returns by gravity, so it is important that the return line has no tight bends.

 

José  

[N201MKTurbo]

I have an m20turbo separator. It was on the plane when I bought it. My plane uses about a quart in 25 hours. I've never ran this engine without it, so I don't know how much the separator helps. The best I got out of any of the three engines I had on my M20F was about a quart in 10 hours.

[DonMuncy]

This is one of the VERY FEW instances where I disagree with Mike Busch. I don't consider the oil mist to be bad stuff. If an air-oil separator will retain the oil and return it to the sump, that would be a good thing. Whether they are really effective, I don't know. But I don't see how they could be damaging to anything.

[Guest]

Within the engine and vent tube there is water vapour which used to be vented overboard. Now we collect it as well as oil mist in the separator can where it returns to liquid form and returns to the oil sump through the drain line. How do I know this to be true? I've installed an Andair water trap in the return line and regularly find water in it.

The goal used to be the fly the engine long enough and hot enough the vent moisture from within the engine overboard, not collect and return it to the engine.

I'd be curious to know how many engine with bad camshafts have oil separators.

Clarence

[aaronk25]

I think that if your run the engine at least weekly a oil separator doesn't do any harm, I'm not convinced it would accelerate corrosion even if not operated.

I installed the largest version of the airwolf oil seperater last summer and considered the m20 but went with air wolf due to it's larger size and because it uses vacuum pump exit air to help push back into engine and the size of the collection unit was larger.

That being said I've heard good reviews with the m20 but it seems the installation configuration is much more critical for successful operation.

[Danb]

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