Air/Oil Seperator

[mtdanet]

Hi All....As you can probably tell I'm working on my engine installation. I need a air/oil separator and was looking at one I found on Ebay and was hoping for your collective wisdom

https://www.ebay.com/itm/Engine-Oil-Reservoir-Catch-Can-Tank-Kit-Breather-Filter-Baffled-Aluminum-0-5L-/372138183089?_trksid=p2349526.m4383.l4275.c10 It looks as if it's well built, nicely finished and a great price with free shipping. With two ports I assume are inlet and atmosphere?? and a drain when oil level needs to be reduced. So what do you think.
Thanks in advance
Blue Skies
John

 

[soneraii]

IMHO you don't need it. I use the GPAS air/oil separator on the top left side of the engine that also doubles as an oil filler port. The unit has a louvered metal piece inside that does an excellent job of diverting oil from the oily vapors back into the crankcase. It takes up no additional space anywhere on the engine or the firewall. I have a hose about 1/2" in diameter coming off it, making a very slight uphill turn to the firewall and then down and out the bottom.

After about a half hour flying, the length of my typical flights, I may get a drop on the floor, frequently nothing.

Sonex sells something similar that mounts in the same place.

Kevin

 

[eschrom]

My experience with the GP breather isn't as good as Kevin's so in addition to it I use a homemade device that sits above the case. The result is excellent - no oil on the belly and none on the hangar floor. My device has only two ports, one that connects it to the GP and the other for a tube that vents to the bottom of the cowl. Whatever accumulates in it eventually runs back to the GP and into the case.

Ed

 

[Pttim]

I have a dirty belly as well! , wait let me rephrase that, my airplane has a dirty belly. : I looked into air oil separators to alleviate this problem and stumbled across an article that made me think a bit. Air oil separators do actually recover the oil vapor and return it to crankcase but what they also do as a side effect is recover the water vapor and also return the water to the crankcase. The case point was that the separator needed to be in a very hot place exceeding 212 degrees so that it could burn off the water vapor before returning it to the crankcase. Since I have no port in the crankcase to return the oil and I cannot guarantee that I can keep the oil separator hot there will be no separator for me. Yes I lose a bit of oil each flight and make a little mess on the belly it just mean my engine is always getting new oil.

 

[Chucker]

Has anyone tried putting a fuel filter in the oil breather line?

If you mounted it vertically on the uphill run from your crankcase vent, the fumes would have to pass through the filter before making the turn and heading out the bottom of the compartment. Any oil that condensed in the filter would be gravity fed back to your case.

I tried breathing through a fuel filter and there seems to be minimal resistance to air flow.

Just a thought....just asking.

OBTW...why I was researching the issue, I found a device called a KrankVent. Something like a PCV valve....only better. They claim that it maintains an optimum vacuum in your crankcase to improve ring seal, increase horsepower, and reduce engine wear.

All the best,
Chucker

 

[Raceair]

With the Formula Vees turning over 4000 RPM, the air / oil separator became much more important. The engines were actually pumping oil out rapidly at those RPM's.....At 3200 to 3600 rpm a separator might not be as important....

 

[soneraifred]

I installed a homemade oil separator on my airplane almost immediately after I started flying it. It keeps 98% of the oil off the belly. I drain the recovered oil back to the engine thru a small hose to the LH valve cover. You can see photos of the install in my photo gallery. It’s the aluminum box mounted on the LH side of the firewall. There’s detailed info on the separator in one of the Sonerai Newsletters.

 

[Bil4381]

Because of the possibility of internal corrosion from water vapor given off from the oil as it reaches say 200F, I would not do anything to recover oil /oil vapour coming out of the crankcase vent. I catch it in a separator and drain it occasionally for disposal.
Bill E

 

[smokyray]

John,
The blueprinted 1835 in 994SP has the latest GP AOS described above that works very well. I would argue it’s merits over a separate unit after positive results and simplicity. The 20W50 synthetic AMS Oil when drained at 50 hours (also have a full flow oil filter) looked new.994SPs belly as you can see on the left, stayed squeaky clean, and I rarely flew it level very long.
.
On the Lycomings in my 2 RV”s (0320,0360) I installed a RV inventors product called the Slimefighter. It’s an in-line AOS installed slightly inclined on the breather line as it exits the case. It works brilliantly. BTW, I have never found any traces of foam, water vapor residue or corrosion in any of my engines during tear down.

When you perform Acro, an AOS is a must.

http://www.airflow-systems.com/air-oil-separators/

V/R
Smokey