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Thread: IO-240B Exhaust Breakage

  1. #1
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    Default IO-240B Exhaust Breakage

    Thought my engine was sounding a little clacky at idle, and not quite right. So decided to
    drop the exhaust to check the gaskets, and flanges. Glad I did, found a cracked pipe on
    CoPilot side rear (covered by the clamp strap), and a broken Flange on Pilot side rear

    None of this was noticeable until I unbolted it and it quite literally fell apart ...

    Might be a good idea to add "Drop and Inspect Exhaust" to your IO-240B Annual ... None
    of these breaks were noticeable with the exhaust mounted.

    Jeff

    Here's a scary break, that was completely invisible before disassembly

    IMG_0134.jpg

    Notice the Break is completely covered by the strap.

    IMG_0135.jpg

    This flange looked fine, but fell into two pieces when the nuts were removed.

    IMG_0131.jpg

    Can see the weld on all these flanges does not completely encircle

    IMG_0133.jpg

  2. #2
    Administrator DesertFox4's Avatar
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    Default Re: IO-240B Exhaust Breakage

    Good catch Jeff. Knowing your aircraft is so valuable. If something sounds different, investigate.


    DesertFox4
    Admin.
    7 Super Sport
    912 ULS Tri-gear


  3. #3
    Senior Member PapuaPilot's Avatar
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    Default Re: IO-240B Exhaust Breakage

    Wow, great find!

    Often cracking like this happens from installing something that doesn't aligned right by forcing parts together, tightening all the clamps and risers. I learned this from working on TSIO-520 Continental engines in the Cessna TU-206. During inspections we always tested these exhaust systems for cracking by applying low pressure air from a vacuum cleaner hose into the exhaust outlet. You spray all the joints with a soapy water solution and look for bubbling. I would recommend doing this rather than dropping the exhaust. If you see excessive bubbles then you will want to start opening up the clamps and dropping the exhaust.
    Phil Nelson
    A&P-IA, Maintenance Instructor
    KF 5 Outback, Cont. IO-240
    Flying since 2016

  4. #4
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    Default Re: IO-240B Exhaust Breakage

    Thanks for posting this Jeff, and Phil great tip on pressure testing, I am going to give that a try . Bruce N199CL

  5. #5
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    Default Re: IO-240B Exhaust Breakage

    Thanks Phil - That's a great idea about the shop vac and soapy water. Would for sure unbolt the plates
    at the slip joints though. Maybe not the flanges at the cylinder head. Very possible to get bubbles at
    a slip joint and not know if it was a crack or the joint ...

    My inclination is to pull the plates. It's pretty simple, and would give you the ability to see where that pipe
    is swaged, since that's where mine started cracking.

    I got 17 - 18 years on it, so I'm not completely surprised to find a problem. I will for sure be very careful
    when I put it together and follow your advice to avoid any stresses as it goes together. That seems very
    good advice. I don't recall at this point how hard it was to put together, I don't think it was very difficult
    but who know's I was more ambitious then ...

    Making the entire thing more alarming, is the blue stain under the fuel pump. Since my engine driven driven
    pump is weeping from right at the low pressure adjust, so it's off to the shop for Inspection/Repair as well.

    Broken Exhaust + Fuel Leak = BAD NEWS.

    Don't skip over stuff on those inspections ...

    Jeff




    Quote Originally Posted by PapuaPilot View Post
    Wow, great find!

    Often cracking like this happens from installing something that doesn't aligned right by forcing parts together, tightening all the clamps and risers. I learned this from working on TSIO-520 Continental engines in the Cessna TU-206. During inspections we always tested these exhaust systems for cracking by applying low pressure air from a vacuum cleaner hose into the exhaust outlet. You spray all the joints with a soapy water solution and look for bubbling. I would recommend doing this rather than dropping the exhaust. If you see excessive bubbles then you will want to start opening up the clamps and dropping the exhaust.

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