How Long is Engine Break-In?

Discussion in 'Maintenance Bay' started by write-stuff, Sep 18, 2019.

  1. write-stuff

    write-stuff En-Route

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    So much conflicting information on this. Even Continental (the manufacturer of my new engine) is noticeably vague about the process. They give instructions for the first two hours of flight, suggest the first oil change at 10 hours, and say the break-in should be completed in the first 25 hours.

    I have 10 hours on the engine and completed the oil change. Oil consumption is very low and my mechanic is pushing to change over to ashless dispersant oil.

    I'd appreciate some comments from those of you "in the know". Change to regular oil, or stick with mineral oil for another 10 hours?
     
  2. MooneyDriver78

    MooneyDriver78 En-Route

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    What kind of cylinders do you have? Steel, chrome, etc


    Tom
     
  3. Checkout_my_Six

    Checkout_my_Six Touchdown! Greaser!

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    when the CHTs drop 20-30 deg.....and oil consumption stabilizes. It took about 35-40 minutes with my nickel cylinders....running Phillips X/C 20w50.
     

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  4. write-stuff

    write-stuff En-Route

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    I should know this, shouldn't I? I'm guessing whatever is standard. Steel? I didn't pay extra for any cylinder upgrades.
     
  5. Ravioli

    Ravioli Ejection Handle Pulled PoA Supporter

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    My opinion means nothing. But,

    If you're operating the engine frequently, switch and go. If she sits a while between flights i'd say no.

    Again, no data or anything like that, just my opinion of things I think i've read.
     
  6. Salty

    Salty Final Approach

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    That.

    My opinion also means nothing, but I was flying mine weekly and I switched to regular oil after the 10 hour oil change and have had no problems. I'm losing less than 2 quarts in 50 hours. I'm at 124 SMOH
     
  7. 1RTK1

    1RTK1 Cleared for Takeoff

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    You could have gone ashless with no other additives from the start.
     
  8. JAWS

    JAWS Cleared for Takeoff

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    Is this after a complete top overhaul, engine overhaul or a single cylinder replacement?

    I was taught to run mineral until oil consumption stabilized and CHT's dropped. A call to Continental would be worth your while for specifics.
     
  9. MooneyDriver78

    MooneyDriver78 En-Route

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    If steel you’re were probably done by end of 2 hours. I added oil after 1st 2 hour break in flight and never added any more.


    Tom
     
  10. Bell206

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    Without more specific info on your engine can't really give a good answer. But I've never found Continental's break-in procedure to be "vague." And usually a 2 hour run time refers to the initial run performed prior to the engine being shipped. Perhaps post the info you received?? Just remember any deviation from the recommended procedure regardless of the engine providers may limit or void certain warranties.

    The last several engines I was involved in came from Airpower which offers this on their website plus the break-in procedure.
    http://www.airpowerinc.com/downloads/PDFs/TCMEngineBreakInFlightTips.pdf
     
    Last edited: Sep 18, 2019
  11. write-stuff

    write-stuff En-Route

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    Continental continues to be vague and doesn't put any specific hour requirement before changing to new oil. They're recommending that I continue to use mineral oil until there is at least 20 hours on the engine. Lots of different opinions on this though.
     
  12. Checkout_my_Six

    Checkout_my_Six Touchdown! Greaser!

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    nothing magic with those numbers.....change at 10 or 20 hrs with a new filter is good.
     
  13. Bell206

    Bell206 En-Route

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  14. write-stuff

    write-stuff En-Route

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  15. RyanB

    RyanB Administrator Management Council Member PoA Supporter

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    Heh, I just looked above and saw someone beat me too it, in posting that link - my bad.

    IIRC, we’ve always gone by 25hrs for the break-in’s at the flight school.
     
  16. write-stuff

    write-stuff En-Route

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    Yep, Bell206, Continental O-470-R. Thanks for the PDF. That's a good one for the files.

    Continental pushes for 20-25 hours on mineral oil, saying 25 hours is no problem. Other knowledgeable sources suggest getting off of mineral early if possible. I've decided to split the difference and run it on mineral oil for 20 hours, then change.
     
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  17. Sinistar

    Sinistar En-Route

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    For Top End Overhaul Only O-470-R:

    The seller did the top end overhaul and flew the first 10hrs. That's when they listed it for sale. Our A&P came with for the pre-buy and watched the oil change along with lots of other pre-buy stuff and then we did mineral oil again. Both the seller's A&P and ours recommended flying it another 12hrs on the mineral oil which we did. You can bet I was watching that dipstick level before and after each of those flights (but I always do anyways). Then we had our A&P do the next oil change. So about 22hrs total for us.
     
  18. Stewartb

    Stewartb Final Approach

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    The real question is which ashless dispersent oil? I've run Phillips XC from first start of my last two engines.
     
  19. Dan Thomas

    Dan Thomas Final Approach

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    Good point. If you used Aeroshell 15W50 the engine would never break in. The cylinders and rings would glaze instead of seating properly. Aeroshell has the Lycoming ant-scuffing additive in it that makes it really slippery and it would hamper the seating.

    Lycoming calls for mineral for the first 25 hours or until temps and oil consumption stabilizes. For their turboed engines they recommend AD oil instead. They also want that engine run hard for the first 2-3 hours, and I always followed their well-defined procedure when breaking in new engines in the flight school's airplanes. Our oil consumption was very low throughout the life of those engines except for the one time the guys were agitating to use a newly-reengined 172 for circuit work, which I discouraged for the first 15 hours; I wanted XC time on the engine. I let them do it and that engine used more oil all through its 2000 hours. I blamed that low-power work for it. Pretty coincidental otherwise.
     
  20. chemgeek

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    10 hours on mineral oil with nitrided steel cylinders. Oil consumption stabilized after 2 hours. Switched to multi weight after that. Burns 2-3 qt between oil changes. Do something similar and you won't harm anything. The main thing is to run hard during initial break in. Oil choice is probably less important, but follow the overhauler instructions to avoid warranty questions.
     
    Last edited: Sep 18, 2019
  21. Dan Thomas

    Dan Thomas Final Approach

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    Two hours is too short a time to determine oil consumption. Ten is more like it. Dipstick readins can be notoriously inaccurate and will vary depending on how long it has sat since shutdown and what the ground attitude might be.

    The engines I installed and broke in used mineral for 25 hours, were run hard for at least the first half of that, and after switching to AD oil they might have used a quart, maybe two, in 50 hours.
     
  22. chemgeek

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    It's real easy. Fly an hour at a time. Before the next flight, check oil level. (Allows time for oil to drain back.) Add only if it goes down by at least a quart. First flight it burned a quart. After second flight and until the mineral oil was drained at 10 hours, the oil level didn't budge. Hence, stabilized at two hours. About 100 hours in either multiweight, it burns 2-3 quarts per 50 hours, which seems good.
     
  23. asicer

    asicer Final Approach PoA Supporter

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    So you can't just start it up and fly it for 4 hours (or however long it takes to run a full tank down to VFR reserves)?
     
  24. write-stuff

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    The deal with mineral oil is that it is "thinner". During the break-in period, the goal is to get metal-to-metal contact between the rings and cylinder walls.
     
  25. MooneyDriver78

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    Sure, I flew ~2 hours, but you probably want to monitor your oil level closely in the beginning to be sure you don’t have an issue.


    Tom
     
  26. chemgeek

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    Exactly. You don't need to try to break it in during the first flight. Indeed, I found a small oil seep after the first few hours due to a loosened oil drain plug. Removed it and replaced with a quick drain, which I needed to do anyway.
     
  27. bnt83

    bnt83 Final Approach

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    What OAT would you prohibit test flight on a new engine 320/360 ish? I'm about to install new cylinders but we are still seeing 90F afternoons here and I really think we want to launch and burn 3 hours of gas minimum on a 50F day on the initial flight.

    In addition to that the nearest runway is closed and I really don't want to taxi as long as required to fly it but rather wait till the near runway is open again.
     
  28. PaulS

    PaulS Touchdown! Greaser!

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    I would trust my mechanic, if I didn't, I would get a new mechanic. Kind of like a doctor.
     
  29. Checkout_my_Six

    Checkout_my_Six Touchdown! Greaser!

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    I'm always second guessing my mechanic.....o_O
     
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  30. Salty

    Salty Final Approach

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    I wouldn't worry that much about OAT for the flight, but a long taxi would concern me.
     
  31. sourdough44

    sourdough44 Pattern Altitude

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    I had a factory new IO-390 ready to go about 14 months back. My understanding is the factory does a test run on a stand. My installer put about an hour on it, then it was my turn. I of course looked on the inter webs for info on the subject.

    I think most of the ‘break-in’ happens in the 1st few hours, <5 for the most part. The normal mentions are, up on the power, low to midlin altitudes, rich, & mineral oil. My 1st oil change was very early, 2 hours or so. I think I was about 25 hours when I went off mineral oil.

    As far as I can tell things are normal now, 110 or so hours since new. This was a new engine, new cylinders would be about the same.
     
  32. Dan Thomas

    Dan Thomas Final Approach

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    That there. Lycoming used to discourage long ground running on a freshly overhauled engine before break-in flight. In their most recent issue of SI 1427 that isn't mentioned, but at some airports the long taxi and idle time would be unfavorable to break-in.

    They don't mention OAT. They DO want engine temps kept within limits, and that, of course, demands accurate gauges.

    See this: https://www.lycoming.com/sites/default/files/Lycoming Reciprocating engine Break-In and Oil Consumption.pdf
     
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  33. MooneyDriver78

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    I went to the airport early, before rush of student pilots with long run ups and slow taxiing. You should still wait for the oil to reach the minimum operational temperature, but be ready to go when it does.
    Do you have an engine monitor?

    Tom
     
  34. bnt83

    bnt83 Final Approach

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    Thank you for posting that!

    This particular engine is in 68 177, its the 150 horse one, the airplane uses every last pony of the engine's capacity, yet on a hot day I can typically climb 10+ minutes straight without exceeding the temps in that link, yes gets warm and I typically consider it temped out at 420F CHT and will level off if I need to burn off some fuel to make another push to my desired cruising altitude (Rarely need to but that's the way I fly it). Most flights I can climb direct with CHTs 400 or less in the summer.
     
  35. Stewartb

    Stewartb Final Approach

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    Minimum taxi time is still the practice. Use full power to take off and maintain greater than 75% power for several hours, minimize landings, etc. Fly on days warm enough so the oil will get to 180*, so mid winter break-ins aren't suggested, depending where you live. Get the break-in instructions from who built the engine and follow them as a condition of warranty. I never change oil until 10 hours. It's a good idea to check the suction screen at the same time. Then I still fly it hard to 25 hours. After that I go to my normal oil with Camguard. Even if you're a mogas guy break it in with avgas.
     
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