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Thread: engine break-in question

  1. #41
    mvivion's Avatar
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    Quote Originally Posted by Eddie Foy View Post
    A cruise prop will allow you to cruise at max without overspeed. Unlike the Borer, it will overspeed at normal climb airspeeds and WOT.
    I hope not.

    MTV

  2. #42
    PerryB's Avatar
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    Ditto. If it overspeeds in climb, you're way underpitched. I'm running an 82-42 on a 150/320 and I turn 2750 flat out and trimmed for level flight.
    That being said, I'd still want more load for break-in.
    Last edited by PerryB; 11-11-2017 at 10:13 AM.
    After Monday and Tuesday, even the calendar says WTF !

  3. #43

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    Lots of Cubs get cylinders broken in successfully using Borer props. Read your favorite manufacturer's break-in power instructions, use the correct oil, and make sure the oil temps get up near 200*. Enjoy the ride! Everyone loves that new engine smell, well, except the burning paint and oil residue smells on the first flight!

    http://www.superiorairparts.com/down...ers/L96-08.pdf

  4. #44
    Eddie Foy's Avatar
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    My 82/44 Borer would overspeed in cruise at WOT. 160 HP.
    Eddie Foy
    "Put out my hand and touched the face of God"
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  5. #45
    Eddie Foy's Avatar
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    Quote Originally Posted by mvivion View Post
    I hope not.

    MTV
    Care to elaborate? Am I misinformed?
    Eddie Foy
    "Put out my hand and touched the face of God"

  6. #46
    PerryB's Avatar
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    Quote Originally Posted by Eddie Foy View Post
    My 82/44 Borer would overspeed in cruise at WOT. 160 HP.
    You originally stated it would overspeed at "normal climb airspeeds and WOT". If that's the case, you are indeed underpitched by a considerable margin.
    A little overspeed at WOT / level flight is no big deal. I'd hazard a guess that a lot of us are pitched like that. If I crank mine open and keep trimming for level until it peaks out, I bust redline by about 50 RPM. Somewhere around 103 mph.
    After Monday and Tuesday, even the calendar says WTF !

  7. #47
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    Quote Originally Posted by Eddie Foy View Post
    High manifold pressure is a function of the throttle. A Borer is called a climb prop because it will allow you to climb out at WOT. You must pull it back in cruise to avoid overspeed.

    A cruise prop will allow you to cruise at max without overspeed. Unlike the Borer, it will NOT overspeed at normal climb airspeeds and WOT.
    I think you might have typo’d. I inserted a correction.

  8. #48
    Eddie Foy's Avatar
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    Quote Originally Posted by CamTom12 View Post
    I think you might have typo’d. I inserted a correction.
    No typo. My 82/44 Borer would climb at WOT and 45 to 60 mph without overspeeding.
    Eddie Foy
    "Put out my hand and touched the face of God"

  9. #49

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    A cruise prop will allow you to cruise at max without overspeed. Unlike the Borer, it will overspeed at normal climb airspeeds and WOT.
    No typo?

    I re-pitched an old prop to get redline on takeoff and didn't get any recognizable takeoff performance improvement but it sure did rattle the plane in high power cruise. I gauged the new Borer to achieve redline in level cruise. Takeoff and climb performance were good with that. New props work better than filed old toothpicks so my comparison is not apples to apples. Very few PIREPS for Borers are.

  10. #50
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    Quote Originally Posted by Eddie Foy View Post
    No typo. My 82/44 Borer would climb at WOT and 45 to 60 mph without overspeeding.
    But your cruise prop would overspeed in the same conditions?

  11. #51
    Eddie Foy's Avatar
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    Quote Originally Posted by CamTom12 View Post
    But your cruise prop would overspeed in the same conditions?
    I honestly don’t recall.
    Eddie Foy
    "Put out my hand and touched the face of God"

  12. #52
    Gordon Misch's Avatar
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    A cruise prop will allow you to cruise at max without overspeed. Unlike the Borer, it will NOT overspeed at normal climb airspeeds and WOT.
    I think the "it" refers to the cruise prop, not the borer.
    Gordon

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  13. #53
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    Quote Originally Posted by Gordon Misch View Post
    I think the "it" refers to the cruise prop, not the borer.
    NO prop should overtach, or come anywhere close, at climb speeds.
    Last edited by PerryB; 11-11-2017 at 06:32 PM.
    After Monday and Tuesday, even the calendar says WTF !

  14. #54
    Steve Pierce's Avatar
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    My 8243 on 150 hp will go over redline in a climb but meets the STC static rpm. New break in procedures for ECI cylinders said you could use AD oil instead of mineral oil. I still use mineral oil for break in and a Sensenich cruise prop. It make a lot higher manifold pressure and I would rather not take the chance.
    Steve Pierce

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  15. #55
    Gordon Misch's Avatar
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    NO prop should overtach, or come anywhere close, at climb speeds.
    Agreed. I guess I was mistaken; I thought the discussion was revolving around the interpretation of Eddie's statement.
    Gordon

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  16. #56

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    Meanwhile, back on the OP’s question... When I had my O-320 upgraded to high-compression, the shop said to run it flat-out as much as I could until a) the CHTs came down (were a bit high at first), and b) oil consumption dropped back to “normal” range. Three hours later, the CHTs were back to normal, and it stopped burning oil. I called the guy to be sure I was OK, and he said “Yeah, that happens every once in a while. If those two items are satisfied, you’re OK to return to normal operations.” That engine burned les than a quart of oil between changes (50 hrs) for the rest of the time I owned it...
    Jim Parker
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  17. #57
    Steve Pierce's Avatar
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    Cylinder bores are machined with more precise processes these dys with less high and low spots so the rings seat in in 3-4 hours on most new cylinders I have installed.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  18. #58
    mvivion's Avatar
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    My experience with six or seven new engines is that most if not all the break in occurs in the first three or four hours. As others have noted, once cylinder and oil temps have dropped off, most of the break in is done. I was always told to continue break in procedures (mineral oil, relatively high and varying power settings, no prolonged steep climbs, etc) till around 20 hours. That’s probably conservative, but engine overhauls aren’t cheap.

    My current C-90 Continental spit quite a bit of oil when I first got it. Engine monitoring instruments are minimal, and the engine was low time (~ 20 hours smoh). I’ve run it hard, and somewhere around 200 hours, the amount of oil on the belly decreased significantly. I suspect that engine hadn’t been properly broken in, but running it hard eventually got it to settle in. That doesn’t always work, but if you don’t see those signs of break in (drop in CHT and Oil temps) keep running it hard. You never know, it may still settle in.

    MTV
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  19. #59

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    Whats the coldest temp one should break in an engine. Lycoming recommends not during extreme cold but doesn't give a number. Need to do it soon up north.
    Thanks
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  20. #60
    mvivion's Avatar
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    Quote Originally Posted by thunderhead85 View Post
    Whats the coldest temp one should break in an engine. Lycoming recommends not during extreme cold but doesn't give a number. Need to do it soon up north.
    Thanks
    id be reluctant to break in an engine at colder than about -10 F. But, at cold surface temps, you often have hard inversions, so takeoff in cold, climb to warmer air.

    But out the bottom line is, can you afford to pickle and park till spring?

    MTV

  21. #61
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    Quote Originally Posted by thunderhead85 View Post
    Whats the coldest temp one should break in an engine. Lycoming recommends not during extreme cold but doesn't give a number. Need to do it soon up north.
    Thanks
    Are you talking Wasilla "cold", or farther North. It hasn't been cold enough to worry about, Yet...

  22. #62

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    Quote Originally Posted by nanook View Post
    Are you talking Wasilla "cold", or farther North. It hasn't been cold enough to worry about, Yet...
    Wasilla Cold. I was thinking I would be ok above 10, below that its hard to maintain oil temps...

  23. #63

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    We should get the January warm week that might be a good time.
    DENNY

  24. #64
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    Quote Originally Posted by thunderhead85 View Post
    Wasilla Cold. I was thinking I would be ok above 10, below that its hard to maintain oil temps...
    Block off your oil cooler and go fly it. That engine is making heat, and the trick is breaking in those cylinders. Those things get hot during break in. Just run the heck out of it and don’t fly it in real cold for the first few hours.

    MTV
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  25. #65

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    Preheat like $35K depends on it!
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