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Thread: Sticking Valve or Bad Valve Guide?

  1. #1
    aeroaddict's Avatar
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    Sticking Valve or Bad Valve Guide?

    Engine; Titan 340, TT 218 hrs (yes a new engine).

    #2 cylinder dropped out and had zero compression on a run up (thankfully).

    Upon inspection, borescope shows carbon build up but not any burnt valves. Exhaust valve appears to be the problem. When cycling the prop thru and watching the valve mechanics, #2 exhaust valve does not fully close. Using your hand and putting slight sideways force on the springs, the vavle will snap close.

    I have tried soaking it with MMO, and have done a couple of run ups, but no compression. Always the same issue described above.

    Any ideas or solutions are apppreciated.
    Thanks RVBottomly thanked for this post

  2. #2
    skywagon8a's Avatar
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    Try Kroil on the stem with the valve closed, let it soak for a while.
    https://www.kroil.com/products/kroil...nal-penetrant/
    N1PA
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  3. #3

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    Quote Originally Posted by aeroaddict View Post

    Any ideas or solutions are appreciated.
    Can you see the valve stem with the boroscope when the valve is fully open? If so, how does this sticking valve compare for build up when compared to an exhaust valve in a good cylinder?

    Perhaps need to pull the exhaust pipe for that cylinder to see the valve stem?

    Either way a bummer on an almost new engine.
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  4. #4
    aeroaddict's Avatar
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    Thanks for the suggestions. I will remove the exhaust pipe, look at the stem and report back most likely tomorrow.

  5. #5
    8GCBC's Avatar
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    Warranty claim?
    2018 R44
    IA/A&P, ATP, SES, CFII, MEI, Rotor PPL (2500 TT)
    http://www.youtube.com/watch?v=SXI48e1heuo

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    aeroaddict's Avatar
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    Update; pulled off the exhaust pipe and borescoped the valve stem. It was coated pretty good. I took the advise of a good friend (A&P also) and blocked off the exhaust port to fill the chamber with MMO. Will let it soak for a day or so.

    Since I have the exhaust basically loose, I will borescope the other cylinders tomorrow. Have a fencing project taking precidence over the plane right now.

    Warrenty claim: of course, but I rather try to fix it and fly if possible.
    Last edited by aeroaddict; 07-20-2021 at 06:07 PM.

  7. #7
    aeroaddict's Avatar
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    Pic: it's a pic of a pic, so not great quality. Looks like a lot of junk built up on the stem.

    Name:  Valve-1.jpg
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  8. #8

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    Quote Originally Posted by aeroaddict View Post
    I took the advise of a good friend (A&P also) and blocked off the exhaust port to fill the chamber with MMO. Will let it soak for a day or so.
    I suppose that might give temporary relief from the problem but it won't answer what caused it or prevent it from happening again.

    I just looked at the exhaust valve from an O-360 cylinder I pulled at about 2,800 hours. It looks a lot better than yours.
    Last edited by frequent_flyer; 07-21-2021 at 12:59 PM.
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  9. #9
    aeroaddict's Avatar
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    Well that IS the question. In most conversations about this the main questions are: how do you lean and do you lean on the ground?

    Answer to both questions is yes, but the buildup would imply not leaning enough(?)

  10. #10

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    If Kroil doesn't do it, try some Hoppies #9. It's great for cleaning fuel injector nozzles as well.

  11. #11
    aeroaddict's Avatar
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    Ha! Hoppies make total sense. Thanks

    I should have more time tomorrow to check the other cylinders for comparison.

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