How much oil burn is too much?

Discussion in 'Maintenance Bay' started by deyoung, Jun 3, 2019.

  1. deyoung

    deyoung Pre-takeoff checklist

    Joined:
    Nov 13, 2014
    Messages:
    365
    Location:
    Tucson, AZ
    Display Name:

    Display name:
    CHD
    I realize that oil consumption may vary quite a bit, but I want to get an idea of what the acceptable range is and when (absent any other signs of a problem) I should start to care?

    Lycoming O-540-B4-B5, currently I usually add a quart maybe every 4 or 5 hours of flight time, give or take. Seems a little high, but no other signs of issues; compressions all in the mid-70s. Last oil analysis showed just slightly high iron but otherwise nothing noteworthy; next one coming shortly.

    Thoughts? Thanks!
     
  2. mondtster

    mondtster En-Route

    Joined:
    Nov 25, 2011
    Messages:
    2,558
    Display Name:

    Display name:
    mondtster
    That doesn’t seem unreasonable for an o-540. I fly and maintain several airplanes with 540s (a total of 7 engines) and they all seem to consume a quart of oil in 4-8 hours. The worst consumer is an Aztec used for training so it has a harder life than the others. Of interesting note, the engine that consumes the least oil is the highest horsepower turbocharged engine.
     
  3. Eric Lehto

    Eric Lehto Pre-Flight

    Joined:
    Aug 5, 2018
    Messages:
    35
    Location:
    Antelope Valley, CA
    Display Name:

    Display name:
    Lombard
    Something else to consider...how full is full? As in, what's the oil level after you add a quart? How about after 5 hrs run time? After 10 hrs? If you fill your sump, your gonna blow a bunch of oil out the breather. In my (very) limited experience, there aren't any engines that will run with a "full" sump without blowing a bunch of oil out the breather.
     
  4. timwinters

    timwinters Touchdown! Greaser! PoA Supporter

    Joined:
    Feb 23, 2008
    Messages:
    12,973
    Location:
    Conway, MO
    Display Name:

    Display name:
    LTD
    As with so many topics in life, "none, all; always, never" is not appropriate or accurate.
     
  5. Checkout_my_Six

    Checkout_my_Six Final Approach

    Joined:
    Mar 4, 2007
    Messages:
    9,328
    Location:
    Maryland
    Display Name:

    Display name:
    Check_my_Six
    yup.....let it get down to 5-6 qts....then tell me how long it takes to use a quart.
     
  6. FORANE

    FORANE Pattern Altitude

    Joined:
    Mar 7, 2013
    Messages:
    2,047
    Location:
    TN
    Display Name:

    Display name:
    FORANE
    Lycoming publishes a max limit on oil consumption.
     
  7. CMongoose

    CMongoose Pre-takeoff checklist

    Joined:
    Aug 13, 2014
    Messages:
    295
    Display Name:

    Display name:
    CMongoose
    That doesn't sound unreasonable to me. My IO-360 burns around a quart every 5 hours on average, although less as the quantity gets closer to 6 quarts as others have noted above.

    From the Operators Manual, it looks like the max consumption on the O-540-B is somewhere between 0.78 and 0.67 quarts per hour.

    O-540 Oil Consumption Limits.jpg

    https://www.lycoming.com/sites/default/files/O & IO-540 Oper Manual 60297-10.pdf page 3-10
     
  8. Timbeck2

    Timbeck2 Final Approach

    Joined:
    Nov 4, 2015
    Messages:
    6,213
    Location:
    Vail, Arizona
    Display Name:

    Display name:
    Timbeck2
    Based on that Chris, I'd say you're good to go.


    BTW - got your name right this time. ;)
     
  9. Dan Thomas

    Dan Thomas Final Approach

    Joined:
    Jun 16, 2008
    Messages:
    5,383
    Display Name:

    Display name:
    Dan Thomas
    Turbocharging discourages oil consumption. The cylinder, except at low power, doesn't experience negative pressures during the intake stroke as an NA engine does, so oil isn't drawn past the rings and valve guides so much.

    I looked after one 540, NA, and I don't remember it using that much oil. Break-in procedure is critical to limiting oil consumption, as is not filling the sump to the max if doing so tends to drop the oil level a lot within a very few hours after that fillup.
     
  10. Clip4

    Clip4 En-Route

    Joined:
    Jun 27, 2013
    Messages:
    4,198
    Location:
    A Rubber Room
    Display Name:

    Display name:
    Cli4ord
    In a 540 with compressions in the 70s and 6 quarts of oil you should use a quart every 10-20 hours.
     
  11. frfly172

    frfly172 Touchdown! Greaser! PoA Supporter

    Joined:
    Oct 22, 2008
    Messages:
    13,348
    Location:
    mass fla
    Display Name:

    Display name:
    ron keating
    Are you burning the quart or blowing it out,due to overfilling.
     
  12. mondtster

    mondtster En-Route

    Joined:
    Nov 25, 2011
    Messages:
    2,558
    Display Name:

    Display name:
    mondtster
    Cylinder pressures are relative, but I get your point. Horsepower, number of cylinders, bore size, cylinder finish, and piston/ring package are just some of the other contributing factors to oil consumption (I’ve done quite a bit of consumption testing).

    All the 540s I’ve been around used oil at a rate greater than one quart in 10 hours regardless of who broke them in (including factory run-ins) and having a reasonable amount of oil in the engine. That’s just been my experience with them, right or wrong.
     
  13. 455 Bravo Uniform

    455 Bravo Uniform En-Route PoA Supporter

    Joined:
    Aug 18, 2015
    Messages:
    2,502
    Location:
    KLAF
    Display Name:

    Display name:
    455 Bravo Uniform
    I find that for my IO-470, with 12qt spec, I will lose a quart very quickly if I fill it up. 10 quarts is the sweet spot. 9 is the lowest recommended. I put a quart in once we get down to 9 from 10, which is about 8-10 hours.
     
    GeorgeC likes this.
  14. deyoung

    deyoung Pre-takeoff checklist

    Joined:
    Nov 13, 2014
    Messages:
    365
    Location:
    Tucson, AZ
    Display Name:

    Display name:
    CHD
    I generally don't let it get below 9, so maybe I'm blowing off more than I'm burning, though I don't notice too much of a mess. Just got the analysis back, which looks normal, though lots of phosphorous - I'll have to look up what that means.
     
  15. Timbeck2

    Timbeck2 Final Approach

    Joined:
    Nov 4, 2015
    Messages:
    6,213
    Location:
    Vail, Arizona
    Display Name:

    Display name:
    Timbeck2
  16. deyoung

    deyoung Pre-takeoff checklist

    Joined:
    Nov 13, 2014
    Messages:
    365
    Location:
    Tucson, AZ
    Display Name:

    Display name:
    CHD
    No, but I've only recently started doing analysis regularly, so I don't really have trend data yet. I use Aeroshell W-100+. The lab didn't seem worried about it, so I won't either for now. :)
     
  17. Bell206

    Bell206 Cleared for Takeoff

    Joined:
    Oct 6, 2017
    Messages:
    1,486
    Display Name:

    Display name:
    Bell206
    I've found that most aircraft engines have a sweet spot for oil levels. Fill above that spot and it gets rid of the "extra" oil every time. Sometimes its it's by engine model, sometimes by individual engine, or both. On a PA-31 with TIO-540s, we ran the L/H engine a quart low and the R/H two qts low. Even turbine engines are the same way. On one particular turbine helicopter we ran them with oil levels just above the minimum mark on the sight glass as anything above that ended up on the tailboom at the end of the day.
     
    mondtster likes this.
  18. Timbeck2

    Timbeck2 Final Approach

    Joined:
    Nov 4, 2015
    Messages:
    6,213
    Location:
    Vail, Arizona
    Display Name:

    Display name:
    Timbeck2
    In my O-320, anything over 5 3/4 quarts will be on the belly.
     
  19. 455 Bravo Uniform

    455 Bravo Uniform En-Route PoA Supporter

    Joined:
    Aug 18, 2015
    Messages:
    2,502
    Location:
    KLAF
    Display Name:

    Display name:
    455 Bravo Uniform
    I wonder if the canting of the engines had something to do with it.

    I also imagine the flight attitudes of different planes and pilot habits in climb, cruise, and descent play a role too, relative to how the oil lays in the sump during those states of flight.
     
  20. Bell206

    Bell206 Cleared for Takeoff

    Joined:
    Oct 6, 2017
    Messages:
    1,486
    Display Name:

    Display name:
    Bell206
    Quite possible. On occasion it was how a person read the dip stick. The same dip stick was used for the LTIO/TIO and had 2 scales engraved on it. So if you read the wrong scale by side, it created an "induced" problem. Eventually we would grind off the dip stick scale not applicable to engine it was installed.
     
  21. Glen R

    Glen R Pre-takeoff checklist

    Joined:
    Oct 25, 2014
    Messages:
    130
    Location:
    Huntington, NY
    Display Name:

    Display name:
    Glen
    The oil capacity on my IO520 is 12 quarts. I put in 10 and a pint of Camguard. I burn a quart about every 23-25 hours. If I put in 12 it winds up on the belly.
     
  22. k9medic

    k9medic Pre-takeoff checklist

    Joined:
    Sep 27, 2018
    Messages:
    174
    Location:
    Florida
    Display Name:

    Display name:
    k9medic
    You numbers fall in line with the acceptable oil burn. On my Cherokee 6, we filled it to 10 quarts and it promptly blew 2 quarts out.

    We run it at 8 quarts and no lower than 6 quarts. Normal flight for us is 5.6 hours and we generally add a quart then.
     
  23. Salty

    Salty En-Route PoA Supporter

    Joined:
    Dec 21, 2016
    Messages:
    3,735
    Location:
    FL
    Display Name:

    Display name:
    Salty
    How much oil burn is too much?

    Enough so that you will drop below the minimum before the flight is over.
     
    hindsight2020 likes this.
  24. Salty

    Salty En-Route PoA Supporter

    Joined:
    Dec 21, 2016
    Messages:
    3,735
    Location:
    FL
    Display Name:

    Display name:
    Salty
    I fill my O-360 to 8 quarts at oil change and typically hit 50 hours before it gets below 6. Before the overhaul it was burning a quart every 5 hours.
     
  25. chemgeek

    chemgeek Line Up and Wait

    Joined:
    Dec 5, 2009
    Messages:
    846
    Display Name:

    Display name:
    chemgeek
    The Lycoming recommendations allow for a ridiculous amount of oil usage for acceptable operation. So you can apparently operate safely, but I would start to investigate if it gets to more than a quart every 4 hours. BTW, you can have excellent compressions and still have shot oil control rings. BTDT. My old O-320 went through a quart every 6-8 hours. (The new one hardly uses a quart every 20 hours.) If you start getting blowby (quickly blackening oil) or periodic oil fouling on lower plugs, I'd be looking to find a fix. The oil is going somewhere: it's either going out the breather or going out the exhaust. If the latter, it could be building deposits where you don't want them. As others have mentioned, some engines are better oil misers if they are not filled to capacity.The O-235-C2C and O-320-E2G engines I've owned preferred to be filled one quart below capacity. If filled to that level, I get the maximum number of hours per quart. I add oil when it gets to 2 quarts below capacity. The O-320s seem really happy running between 6-7 quarts out of 8 max, even when new. Oil usage in and of itself is not necessarily a problem. Combined with other issues, it could be a sign of needed maintenance.
     
  26. George Mohr

    George Mohr Pre-takeoff checklist

    Joined:
    Oct 10, 2016
    Messages:
    417
    Location:
    New Jersey
    Display Name:

    Display name:
    Gmohr
    Yeah but the limit is SCARY high, like 1QT per hour or something like that. Yikes.
     
  27. Capt. Geoffrey Thorpe

    Capt. Geoffrey Thorpe Touchdown! Greaser! PoA Supporter

    Joined:
    Jun 7, 2008
    Messages:
    11,189
    Location:
    DXO124009
    Display Name:

    Display name:
    Light and Sporty Guy
    I usually speed the playback up to at least 1.5 times if not 2 times.

     
  28. JAWS

    JAWS Line Up and Wait

    Joined:
    Oct 7, 2016
    Messages:
    908
    Display Name:

    Display name:
    JAWS
  29. Cap'n Jack

    Cap'n Jack Final Approach

    Joined:
    Jun 25, 2006
    Messages:
    6,466
    Location:
    Nebraska
    Display Name:

    Display name:
    Cap'n Jack
    At near that rate, does it become a continuous oil change?

    :):):) J/k
     
  30. hamer

    hamer Pre-takeoff checklist

    Joined:
    Jun 15, 2018
    Messages:
    210
    Location:
    SoCal
    Display Name:

    Display name:
    hamer
    I like his webinars, but damn he talks slow. Never thought to speed them up. Good tip.
     
  31. pigpenracing

    pigpenracing Pattern Altitude

    Joined:
    Feb 8, 2012
    Messages:
    2,230
    Location:
    Brenham Tx
    Display Name:

    Display name:
    pigpen
    I wouldn't run a 12 quart capacity 540 with 5 quarts :confused:
     
  32. Checkout_my_Six

    Checkout_my_Six Final Approach

    Joined:
    Mar 4, 2007
    Messages:
    9,328
    Location:
    Maryland
    Display Name:

    Display name:
    Check_my_Six
    why?....it will do just fine with much less. Why do you think it was certified to 12?

     
    Last edited: Jun 13, 2019
  33. pigpenracing

    pigpenracing Pattern Altitude

    Joined:
    Feb 8, 2012
    Messages:
    2,230
    Location:
    Brenham Tx
    Display Name:

    Display name:
    pigpen
    The more oil the cooler the oil temp will run and the cleaner the oil will stay.....
    I would run a 540 with 9-10.
    Not 5 :confused:
    Maybe I take care of my engines better?
     
  34. Checkout_my_Six

    Checkout_my_Six Final Approach

    Joined:
    Mar 4, 2007
    Messages:
    9,328
    Location:
    Maryland
    Display Name:

    Display name:
    Check_my_Six
    No...just do that to determine "oil consumption". Keep up pal....
     
    pigpenracing likes this.