Thanks Thanks:  0
Page 1 of 2 12 LastLast
Results 1 to 40 of 46

Thread: Breather Separators

  1. #1
    JP's Avatar
    Join Date
    Mar 2003
    Location
    The Big Woods of Maine
    Posts
    2,989
    Post Thanks / Like

    Breather Separators

    Anyone have any pictures of the installation of an M20 Air/Oil Separator on a small Continental (65-90). Am going to be installing one on my C-90 and would love some advice, hints and pics if anyone has some....
    JP Russell--The Cub Therapist
    1947 PA-11 Cub Special
    www.bft-int.com/aviation.html

  2. #2
    Ruidoso Ron's Avatar
    Join Date
    Oct 2003
    Location
    Alto, NM
    Posts
    1,779
    Post Thanks / Like
    Jeff, I have heard that it's not a good idea on our little engines (Lycs either). The reason is that the oil temp never gets hot enough to boil out the moisture (needs 200*, or better), and the separator simply dumps it back into the oil tank. I have had a couple of engine guys confirm my thoughts.

  3. #3

    Join Date
    Apr 2003
    Location
    Clearwater,Fl
    Posts
    2,501
    Post Thanks / Like
    Is it for water or to keep you belly clean?

  4. #4
    behindpropellers's Avatar
    Join Date
    Feb 2003
    Location
    NE Ohio
    Posts
    6,528
    Post Thanks / Like
    I think JR just wants to add another gadget to his plane....

  5. #5
    Steve Pierce's Avatar
    Join Date
    Mar 2002
    Location
    Graham, TX
    Posts
    16,201
    Post Thanks / Like
    I can give you the does and don'ts on the M20 for the C90. Plus a little theory on air/oil separators. I will get my pictures and post the rest. Trying to get the pacer ready for Sun & Fun and am pooped.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  6. #6
    a3holerman's Avatar
    Join Date
    Jul 2006
    Location
    Cape Cod
    Posts
    237
    Post Thanks / Like
    Hi,
    Not the same, but had one on my Deb with a IO470. At 600hrs since freman it was a rust bucket inside. I had bought it at 500 hrs but it flew 100+ a year previously. It had a air/oil sep on it. When the new engine was installed we removed the separator and never looked back. I have heard other tales of similar happenings. In a cub it seems like just DDW or detrimental dead weight.

  7. #7
    Roger Peterson's Avatar
    Join Date
    May 2004
    Location
    Sweeny, Texas
    Posts
    1,454
    Post Thanks / Like
    I don't use a oil separator on a small engine because it dumps so much water back in the engine. Just tie a plastic baby bottle over the end of the breather hose and you will see how much water that little engine is making. You may have to cut off the breather hose to keep the bottle up out of the airstream.
    Roger
    Based at O8XS. Sweeny Texas (Winter)
    Finlayson Lake, Ontario (Summer)
    I plan on living forever.......so far, so good !!!

  8. #8
    Steve Pierce's Avatar
    Join Date
    Mar 2002
    Location
    Graham, TX
    Posts
    16,201
    Post Thanks / Like
    My understanding of the way an air/oil separator works comes from my Dad who is a mechanical engineer and worked for Cummins Engine Company until his retirement. When he was setting up test cells to test run engines they needed air/oil separators and he did a lot of research on them. The oil is never a vapor, therefore it is in little droplets (mist) suspended in the air coming out of the crankcase. When the oil droplets contact the fine screen in the air/oil separator it sticks to the screen and runs into the bottom of the separator and back into the crankcase. Water is a vapor in the air and it goes out the vent as a vapor. The stuff in the bottom of the baby bottle is condensed water vapor like what you get out of your air compressor. When the air is cooled the water in the air condenses forming water droplets Cummins used to run the engines on the test cell for 50 hrs. while dumping water into the engine every hour. There was never any water found in the oil, it vaporized as long as the engine was brought up to temp. Cars don't dump crankcase pressure overboard, it all goes back into the engine.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  9. #9
    Roger Peterson's Avatar
    Join Date
    May 2004
    Location
    Sweeny, Texas
    Posts
    1,454
    Post Thanks / Like
    it vaporized as long as the engine was brought up to temp
    I have one C85 that the entire filler tube on the oil kidney is rust. It also runs very cool on the J3. It also had a separator on it. I don't think the water vaporised very good at 160 to 180 deg

    Regardless, the baby bottle sure keeps the oil off the belly.
    Roger
    Based at O8XS. Sweeny Texas (Winter)
    Finlayson Lake, Ontario (Summer)
    I plan on living forever.......so far, so good !!!

  10. #10
    Clyde and Susan's Avatar
    Join Date
    Dec 2005
    Posts
    602
    Post Thanks / Like
    I have been thinking about using an air-oil separator also on my Cubs. I was about talked out of it , but now I'm not so sure. Has anyone tried feeding the output of the separator into a bottle temporally to see what is actually coming out that would otherwise go back to the oil sump? It seems to me that would settle it. ...Clyde Davis

  11. #11
    Rookie's Avatar
    Join Date
    Jun 2002
    Location
    WA
    Posts
    490
    Post Thanks / Like
    So Steve, just to be clear, you're saying you think the M20 is okay for the Super Cub engines?

    I had an M20, but didn't end up installing it when my mechanic balked at the idea. His additional point to the above discussion is that if you start to blow more oil than usual, that can be a useful clue that is masked by the presence of the air oil separator.

    -->Aaron

  12. #12
    Roger Peterson's Avatar
    Join Date
    May 2004
    Location
    Sweeny, Texas
    Posts
    1,454
    Post Thanks / Like
    That is why I started using the bottle in the first place. To see what and how much is coming out of the engine.
    Roger
    Based at O8XS. Sweeny Texas (Winter)
    Finlayson Lake, Ontario (Summer)
    I plan on living forever.......so far, so good !!!

  13. #13
    Steve Pierce's Avatar
    Join Date
    Mar 2002
    Location
    Graham, TX
    Posts
    16,201
    Post Thanks / Like
    I have changed a lot of oil and never seen the stuff I have seen in the baby bottle or that is dripped on the hanger floor in the winter in the oil drain bucket.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  14. #14
    Marc Olson's Avatar
    Join Date
    Feb 2003
    Location
    Seattle, WA
    Posts
    363
    Post Thanks / Like
    The O-320 on 64M came into my possession with a 'separator' and an oily belly. Along with poor compressions, high oil temps and a thirst for oil.

    After a rebuild it doesn't burn oil, run hot, or leave oil on the belly. Well, not much.

    These aren't radial engines, after all.

  15. #15
    SJ's Avatar
    Join Date
    Jan 2002
    Location
    Kansas City, USA
    Posts
    13,315
    Post Thanks / Like
    I have had two experiences of the M20 making the problem worse than better, 135hp and 180hp lyc. I pulled it off my cub and life is good now.

    sj
    "Often Mistaken, but Never in Doubt"
    ------------------------------------------

  16. #16

    Join Date
    Nov 2004
    Location
    Anchorage, Alaska
    Posts
    7
    Post Thanks / Like
    I put an air oil separator on an O-235. I started noticing condensation on the dipstick so I disconnected the drain line to the case and plugged it. I went and flew for about an hour. When I came back I drained what had accumulated. About a cup of water came out! I have since removed and stored my air oil separator.
    Also about that baby bottle trick. Not wanting to degrade the supreme quality of my cub I went and bought a deluxe version with a rubber nipple and disposable liners. I cut the nipple so it was a nice fit over the breather line and off I went. Also at the same time I changed from 50wt to 30 wt oil for the winter. Went flying and came back with oil all over the side of the airplane so I started chasing oil leaks. I thought it was due to the thinner oil. After several flights and much oil wiping I found a cracked pushrod tube and a leaky valve cover. On the next flight there was oil all over the front of the engine apparently coming out of the front seal. All the oil leaks had been on the right side of the engine so that was where my concentration was. The clue light came on when I notice some oil on the inside of the left cowling lined up with the weep hole on the breather tube. I then realized the baby bottle was not vented and the weep hole was not big enough to properly vent the case so the case was pressurizing. What had happened was with only the weep hole providing the vent the case was pressurizing just enough to force oil out of every slight leak. When I sealed all the little leaks the last place for it to go was out the front seal. I then cut a half dozen holes around the perimeter of the nipple and flew with no oil leaks. I flew the baby bottle in the winter and noticed how much water it collected and I was worried it might freeze and block the breather so I removed it.
    Moral of the story. If it ain't broke don't fix it. These planes have been around a long time so think twice about adding new gadgets. Weep holes are good!

  17. #17
    JP's Avatar
    Join Date
    Mar 2003
    Location
    The Big Woods of Maine
    Posts
    2,989
    Post Thanks / Like
    As always, the input of the Learned Community has been very, very helpful. I've got some pitting from the long-term engine storage which has resulted in blow-by. Otherwise compression, etc. are all fine.

    The cure is simple--cylinder overhaul/replacement, which is on my list of things to do when there is a bit more moolah in the till.

    I thought in the interim that the M-20 might do the trick, but now am thinking differently.
    JP Russell--The Cub Therapist
    1947 PA-11 Cub Special
    www.bft-int.com/aviation.html

  18. #18
    Steve Pierce's Avatar
    Join Date
    Mar 2002
    Location
    Graham, TX
    Posts
    16,201
    Post Thanks / Like
    Jeff, I built up a C90 for the Super Cub I fly with new cylinders, Divco overhauled the crankcase and Aircraft Specialties Services did all the internal steel. The engine still blew oil out the breather. The M20 helped a lot. Did everything to an O-290 trying to get it to quit blowing and nothing worked including the M20. On the 90hp SC I brought the vent elbow straight back and mounted the M20 just inboard of the filler neck. There is a plug in the side of the case that the oil can be drained back in by. I have seen people put air/oil separators on with a quick drain on them so they could drain the oil out rather than let it return to the sump.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  19. #19
    Roger Peterson's Avatar
    Join Date
    May 2004
    Location
    Sweeny, Texas
    Posts
    1,454
    Post Thanks / Like
    Take a engine that has a lot of blow-by and take the breather tube and put it in a jar of water and watch it bubble. Now take the drain tube that comes off the separator and do the same thing. Same amount of bubbles. Now take the filler cap off and watch the oil fly out the filler tube. Pressure is the same at all three ports. The purpose of the breather tube is to relieve the pressure in the crankcase. A oil separator would sure work better if it were working across a pressure differential, but it isn't. You are betting on the air going through and the oil not. Could it be that it is also causing some added back pressure. Why not dump the breather back into a low pressure area like the intake.

    Or, if you just want to keep oil off the belly and know what the engine is putting out, put a bottle on it or a cork in it.

    If the oil separator were good science, all engines would have them. But, they are more like mother-in-laws. Some people like um and some don't.
    Roger
    Based at O8XS. Sweeny Texas (Winter)
    Finlayson Lake, Ontario (Summer)
    I plan on living forever.......so far, so good !!!

  20. #20
    Steve Pierce's Avatar
    Join Date
    Mar 2002
    Location
    Graham, TX
    Posts
    16,201
    Post Thanks / Like
    I have had good luck on some airplanes by moving the vent tube as it exits the cowl. Some as little as an inch out of the sweet spot would blow oil all over. Some of the experimental and aerobatic guys vent it to the exhaust.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  21. #21
    cruiser's Avatar
    Join Date
    May 2002
    Location
    South Glens Falls, NY
    Posts
    1,240
    Post Thanks / Like
    Cessna or Continental has a "mod" on the 0200 powered Aerobats for extending the fitting that the breather tube attaches to into the case an additional 1 & 1/2" or so, I don't have the exact length of this extension off the top of my head. This was to reduce blow by on the belly due to Aerobatic maneuvers allowing oil vapors to be sucked into the breather tube. http://www.cessna120/140.org/forum/f...eather_mod.pdf If this link does not work, there is supposed to be a line between breather and mod that does not appear, not a dash and I don't know what it would be called. Go to the 120/140 site for the info if interested. This mod worked well on my 0200/PA-11 even though I go inverted by accident only. Jim

  22. #22
    JP's Avatar
    Join Date
    Mar 2003
    Location
    The Big Woods of Maine
    Posts
    2,989
    Post Thanks / Like
    Yeah, I think that's simply the brazed extension on the tube into the crankcase. Heard good things about that. Should be easy enough to do....
    JP Russell--The Cub Therapist
    1947 PA-11 Cub Special
    www.bft-int.com/aviation.html

  23. #23

    Join Date
    Dec 2003
    Location
    new jersey
    Posts
    71
    Post Thanks / Like
    ON the small continentals I have had good luck with turning the crankcase breather fitting 180 so it points up, then run the breather line across the top of the engine then down. On a J3 it also helps keep that line from freezing up. If you can get one, use the 0-200 fitting.

  24. #24
    Roger Peterson's Avatar
    Join Date
    May 2004
    Location
    Sweeny, Texas
    Posts
    1,454
    Post Thanks / Like
    Tried the brazed extension on one and it did help. But it had the vac pump gears in it. Took them out and it was lot better.
    Roger
    Based at O8XS. Sweeny Texas (Winter)
    Finlayson Lake, Ontario (Summer)
    I plan on living forever.......so far, so good !!!

  25. #25
    Hardtailjohn's Avatar
    Join Date
    Jan 2007
    Location
    Marion, MT
    Posts
    525
    Post Thanks / Like
    I saw a 206 here one year that had a tube all the way down the belly to the tailcone..... he said it was cheaper than a top overhaul .
    JH

  26. #26
    WindOnHisNose's Avatar
    Join Date
    Apr 2003
    Location
    Corcoran MN
    Posts
    3,661
    Post Thanks / Like
    OK, so I bought an Airwolf air-oil separator and after Bob Eckstein looked it over and noticed that the spin-on oil filter adapter would have to be seriously moved to permit installation, I looked at the M20 (it is smaller), and it may work. Reading the comparisons made by Airwolf (http://www.airwolf.com/size_really_does_matter1.htm) I have decided I need a pretty good reason to install either the M20 or the Airwolf. Any new thoughts since 04/11/2007?

    Thank you.

    Randy

  27. #27

    Join Date
    Jan 2012
    Posts
    1,789
    Post Thanks / Like
    Randy,

    Look in the member section in tech articles and find Vidir's breather design drawings. It's essentially a sophisticated baby bottle oil condenser with the addition of a drain valve. I started to make one but my plane doesn't drool enough to need it. The beauty of it is that it doesn't put the condensed spooge back into the crankcase.

    I hope Vidir is doing well.

    SB

  28. #28

    Join Date
    Oct 2012
    Posts
    2,254
    Post Thanks / Like
    Old thread resurrected. I just came across a breather oil condenser that I'd never seen before. No return line, no emptying it. Interesting.
    http://www.aircraftspruce.com/catalo...uperSlime2.php

  29. #29
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    7,009
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    Old thread resurrected. I just came across a breather oil condenser that I'd never seen before. No return line, no emptying it. Interesting.
    http://www.aircraftspruce.com/catalo...uperSlime2.php
    Interesting idea of which I would like to know more of what is inside. This type of device would need to be installed in an area which is always warm. If not the oil could congeal blocking the breather leading to other problems. Those of you who operate in very cold locations should give this some thought before making the installation. Maybe a small electric heater?

    I've had a breather outlet freeze over and would not want a repeat. It blew out the screwed in dipstick on a Lycoming 0-320 with ALL of the oil blasting out RIGHT NOW.
    N1PA

  30. #30
    txpacer's Avatar
    Join Date
    Jun 2011
    Location
    Iowa Park, TX
    Posts
    349
    Post Thanks / Like
    I put a Slime Fighter in an O-200 Cub and have been very happy with it. We used to have to pour the oil out of the snot bottle every few hours. Now it collects mostly brown water. I've got it in the breather line above the #3 cylinder. That gives it the right drain back angle and keeps it warm.

  31. #31
    PerryB's Avatar
    Join Date
    Aug 2007
    Location
    Northern Calif.
    Posts
    1,200
    Post Thanks / Like
    Quote Originally Posted by skywagon8a View Post
    Interesting idea of which I would like to know more of what is inside. This type of device would need to be installed in an area which is always warm. If not the oil could congeal blocking the breather leading to other problems. Those of you who operate in very cold locations should give this some thought before making the installation. Maybe a small electric heater?

    I've had a breather outlet freeze over and would not want a repeat. It blew out the screwed in dipstick on a Lycoming 0-320 with ALL of the oil blasting out RIGHT NOW.
    I bet that was fun!
    After Monday and Tuesday, even the calendar says WTF !

  32. #32
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    7,009
    Post Thanks / Like
    Fortunately it was in a Colonial C-1 so the oil went on the tail instead of the windshield AND I was within gliding distance to an airport. Other than the mess, there was no harm done.
    N1PA

  33. #33

    Join Date
    Oct 2015
    Posts
    244
    Post Thanks / Like
    That small continentals I've seen the water separator discharge onto the exhaust pipe It looks like that works

  34. #34
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    8,301
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    Old thread resurrected. I just came across a breather oil condenser that I'd never seen before. No return line, no emptying it. Interesting.
    http://www.aircraftspruce.com/catalo...uperSlime2.php
    my guess is summer only for that.... bet it would freeze up in winter

    any one use one a bunch in very cold temps yet???

  35. #35

    Join Date
    Oct 2015
    Posts
    244
    Post Thanks / Like
    Slitthe Breather line to drill a small put a hole you will help minimize the chance of freezing

  36. #36
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    8,301
    Post Thanks / Like
    Quote Originally Posted by Yarddart View Post
    Slitthe Breather line to drill a small put a hole you will help minimize the chance of freezing

    No, you do that to help keep from blowing nose seal out AFTER YOU HAVE FROZE UP, not that it helps prevent it at all

  37. #37
    txpacer's Avatar
    Join Date
    Jun 2011
    Location
    Iowa Park, TX
    Posts
    349
    Post Thanks / Like
    There is a service bulletin on Pitts to drill a hole in the breather line. My solution is to live in Texas. Not much of a problem here.

  38. #38
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    8,301
    Post Thanks / Like
    Quote Originally Posted by txpacer View Post
    .. My solution is to live in Texas. Not much of a problem here.
    but if it hits 70 F I gotta quite working or i break out in lumps and my skin falls off... can't sweat...

    but if it gets cold, i put on boots and gear and am all happy

  39. #39

    Join Date
    Jan 2017
    Location
    Utah/Alaska
    Posts
    23
    Post Thanks / Like
    Oil temps temps need to be at least 160 ° for an hour to get the condensation out of the oil. If the moisture stays, it mixes with the crap leftover from the combustion process and form acids in the oil and you get subsequent corrosion inside the engine. Getting the blowby out helps in the process. Tim

  40. #40
    Farmboy's Avatar
    Join Date
    Jan 2016
    Location
    Glens Falls, NY
    Posts
    697
    Post Thanks / Like
    Since you revived this thread again, it seems to me that the first thing is to find ways to ensure proper operating temperatures, and then see the best way to address the venting. Just like a diesel needs 190 degrees, gas needs at least 160. My C-90's sweet spot seems to be 190-195 for the perfect combination of oil pressure and temperature. If you push over 200 oil pressure starts decreasing, and if you are under 160 oil pressure is cranked.

    On skiboats that run on private lakes as a bouyhead tractor, the oil change needs to be done at 25 hours instead of 50 because the engine will "make oil". Meaning that although the engine temp gets up to 160, the oil never reaches operating temp to burn off the blow-by, and therefore the oil level will increase on the dipstick due to the lack of burn-off.

    (Tournament type of private ski lakes are often just long enough for a ski course, and the boat will run 15-16 seconds at 34/36 mph, and then back to idle. Even doing this all day will never get the oil hot enough to burn off contaminants)

    Baffles, operating cowl vents, duct tape, foam inserts..... get it to temp.

    pb

Similar Threads

  1. Oil Separators
    By akcubflier in forum Super Cub Sick Bay
    Replies: 1
    Last Post: 08-23-2003, 05:26 PM
  2. oil from the breather
    By M1 in forum Super Cub Sick Bay
    Replies: 10
    Last Post: 02-07-2003, 12:09 AM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •