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Topic-icon Air Oil Separators - Airwolf

  • james Long
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7 months 3 weeks ago #1616

I installed Airwolf air oil separators on my 1982 Seneca III a week ago. I was looking for anyone who has had experience with using Airwolf or any other brands of air oil separators. I purchased my Seneca 5 months ago. a 300 hour and 1700 hour engine on TSIO360-KB with turbo chargers. 220 hp. I was getting oil coming out of the breathers. More out of the low time engine but I cleaned the bottom of the wing almost every flight. Very annoying but the mechanic said they have a tendency of breathing out oil. I did not have much consumption but amazed the amount on the bottom of the wing. By the way compression is good on both engines and there are no leaks on either engine. So I installed Airwolf separators flew a 2.5 hr flight and on decent I started loosing oil pressure. I was shooting an approach into low overcast with plenty of ice so I did not want to shut down engine. After landing I checked and was down to 2.25 qts in high time engine and low time engine down by 1 qt. Oil all over bottom of high time engine wing and puddle of oil at the base of the scat tube of the separator. Even the low time engine had oil under wing - again. After cutting open the filter and with no metal in filter I filled up oil, disconnected the separator on the high time engine and flew 45 min legs to verify oil and all seemed OK all the way back home and is currently in shop as they are trying to figure out what happened. Does anyone have any experience with this? good or bad?
Any info would be greatly appreciated. I know they have talked to Airwolf but with the Holiday around us not a lot of info yet but they said it was hooked up properly.

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6 months 3 weeks ago #1667

It’s a great question. Air-oil separators are a bit of a mystery to me as well. I too would like to read the brain trust opinion on this device.

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6 months 2 weeks ago #1677

Air oil separators are subjects of some disagreement.
Cessna put very small ones on some of its twins but to my knowledge they never put one on a single.
First, realize that engines puke out oil above a certain level. If you're filling the sump to the top, there's almost a 100 percent chance the engine will blow oil out of the breather tube until is get's to a certain level. You can tell where that oil level "sweet spot" is by watching the consumption. At a certain level the usage will stabilize. That's the sweet spot. Once an engine is at its sweet spot usage should slow considerably.
One set of opinions says that air oil separators return not only oil-which is ok--but also water vapor which is definitely not OK to the engine.
It's important to realize that there will always be oil dripping out of the crankcase vent overboard hose.
Engines can have good compression yet still be leaking a lot of combustion gasses past the rings into the crankcase. When the pressure in the crankcase is elevated that blows oil out of the engine. This leakage is easy to spot--the oil gets black very soon after an oil change--talking 5 to 10 hours.
Continental motors does have a service bulletin that details a test to check for excessive crankcase pressures. This test connects an airspeed meter or a manometer to a fitting that has been installed in the oil filler cap. This test is outlined in Continental Manual M-0, page 8-24. The maximum pressure allowed in the Continental 360 series is 90 mph or 4 inches of water.
If the pressure is high this manual says to clear the crankcase breather tube and system, and if a air oil separator is installed, dis connect the separator and test again.
If the AirWolf air oil separators are not installed exactly per the instructions, they will not work as designed. Check to see that they are correctly installed.
Another thing that can cause excess crankcase pressure is a leaking prop shaft seal. If your prop shaft seal is old, that could be the cause.
Find the oil level "sweet spot." make sure the separators are correctly installed and go from there.
Let me (us) know what you find

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6 months 1 day ago #1698

Steve a question for you. How can you tell if the prop seal is leaking? here are some stats after I sent my original blog. 4 weeks ago I had the Air/Oil pulled off the high time engine and put it back to factory specs. The low time engine I left the Air/Oil on. (BTW customer support Airwolf was great) The decision, by both Airwolf and my tech, was that too much blow-by so pressurized the crankcase and forced the oil to back flow into the Air/Oil which then blew it overboard. we did boroscope (sp?) and saw 1 valve that seems to be burnt but not bad enough that I have to handle now. Unfortunately I have not been able to fly to verify the results. My tech said on the high time engine he could hear the air come out of the breather during compression test. They do not have the "manometer" but just listened to it. Question is if compression is 68-72 on all cylinders for a 1800 hr engine how could there be so much pressure coming out? If there was rust/broken ring to let the compression blow into crankcase then how could the compression be so good? And I look at oil every time I out to the hangar and the oil on the high time engine does not turn black any faster than the 400 hr engine. So at this point I am going to just keep wiping down the bottom of the wing until I replace the engine. what are your thoughts? (I forgot to mention is I live close to our local re-builder Buldoc and I was told they have the manometer and was thinking about having them check it also)

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6 months 12 hours ago #1699

Hi, I think I would make an appointment at Bolduc to get the test done.
I bought a manometer off of Amazon--it cost $35, so you can get one without breaking the bank but how many times are you going to use it?
Then you have to get an oil filler cap and drill and tap it for a fitting, then do the test.
Second, did you ever establish the oil level "sweet spot" for your engines?
Or are you filling the sumps prior to each flight??
The fact is these engines will run and run if the ignition it timed correctly, they are flown regularly and there is sufficient oil (preferably clean--changed regularly) and there is always sufficient fuel.
My suggestions:
1. Take it to Bolduc and get him to do the crankcase pressure test. If it's high while being run up on the ground, that eliminates the prop shaft seal as a source of the high crankcase pressures; if the pressure is not high during the ground test, change the prop shaft seal.
Let me know what you find.

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  • james Long
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6 months 9 hours ago #1700

Thanks Steve and I will call Buldoc tomorrow and see when they can test. The plane is flown regularly, at least usually. it is rare the plane is not flown every 10 days of less. I did not understand the "fill the sump'? Yes to the sweet spot. 6-7 qts. over 7 each engine likes to kick out. My thought process is if close to 5 qts than add 1 quart. that leaves 6-6.5 qts in all the time. As a note I keep the hangar at 40 degrees and I also have Tanis heaters and I leave them plugged in.

I will know what I find and as always thanks for taking the time for your advice.

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