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Broken exhaust after turbo. Thoughts?

Discussion in 'Engines' started by Prospective, Sep 9, 2020.

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  1. Prospective

    Prospective Senior Member

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    Was heading home after a beautiful labor day weekend here in the north east. Cruising on plane as normal when the tone/sound of the engines changed noticeably. Quick check of gauges showed no loss of RPM, Oil Pressure, Turbo Pressure, or Temp. Pretty quickly, dark smoke appeared out the exhaust of the PORT engine.

    Came down to idle on both engines and smoke stopped. Opened up engine room to find it pretty thick with exhaust smoke. My initial thought was I'd lost a turbo on the port motor and that explained the back smoke and change in engine sounds. But thought it odd that engine didn't appear to lose power or RPM and turbo boost looked ok.

    On further inspection of a hot and smokey engine room, found that exhaust elbow on STARBOARD engine had become disconnected from turbo outlet. As best I could tell as it was difficult to inspect, some kind of coupler had torn or broken. My working theory is that when the starboard motor started exhausting into the engine room, the port motor sucked up that foul air and that's why that is where I saw the black smoke. Make sense?

    I know this was lame but I was able to wrap the joint in heavy aluminum foil and rescue tape to keep the engine from ejecting soot into my engine room. I was then able to make weigh about 8.5knts without turbo's spooling up and after a 6 hr slow cruise, got the boat to the yard where my mechanic is. I am now waiting to hear from him.

    Other than repair of this connection (and I'll have the one on the other engine done too) and I imagine replacing the air filters, is there anything else I should do or check? Engine room is filthy with soot and will need a serious deep cleaning. I think the root cause of this is a broken support collar that goes around exhaust elbow and is supported by a stainless strut. I found that broken last season. So I replaced it at the beginning of this season. But the added vibration prior to repair may have been enough to compromise the connections.

    Let me know if anyone has any other thoughts or suggestions on my course of actions.

    Thanks.
  2. NYCAP123

    NYCAP123 Senior Member

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    Good trouble shooting and get home repair. Sounds like you're on the right track. Check both exhausts end to end. Ran into the same problems on a set of Manns several years ago. Exhaust elbow rotted. Spent a week cleaning the engine room while waiting for the new parts. Lots of fun in your near future.
  3. d_meister

    d_meister Senior Member

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    I've seen that happen on a Detroit 8V92, where the T-bolt type of clamp that secures two parts of the exhaust flanges together simply broke and fell off. Exact same results, except the operator continued to run the engine with RPM and load to return to San Diego from Mexican waters. Made a terrible mess; everything in the engine room coated with a thick layer of greasy soot.
    You did well with the MacGyver fix.
  4. Capt Ralph

    Capt Ralph Senior Member

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    NEW Air filters AND oil-filter change.
    Marine air filters mostly keep larger debris out of the engine.
    After market air filters may do a better job (Oiled K&Ns) but your engines still digested engine soot.
    Thank goodness for a short time and avoided serious engine issues.

    Now, Consider an insurance claim.
    AND get their or your own surveyor on board ASAP before the mechanic starts monkeying with evidence and exposing himself.

    The clean up waste is considered hazardous material. Haz-Mat suites and goggles should be used when in the bilge.
    Turn your bilge pumps off and wash complete. A large Shop vac with a HEPA filter can be used to suck out all wash down material and water.
    This has to be collected haz material also.
    Any air gaps to the living spaces, engine access hatches, ventilation passages need attention to ensure passengers will not be in contact with these materials in the future. New bilge blower hose and maybe the blowers may be considered.

    Our company spear headed a similar project for FDDA many years ago on a Pershing.
    While FDDA rebuilt the main engines and replaced the gen-sets because of leaking MTU exhaust manifolds, We subed out the clean up crew.
    The first crew we fired in about 15 minutes when we caught them just starting to wash out the ER and pump it over, The second company did it correctly.
    MTU warranty covered all expenses very well.
  5. Prospective

    Prospective Senior Member

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    Capt Ralph,

    Thanks for the reply.

    2 questions...

    -Why a possible insurance claim on something that's basically a wear issue on a 20yr old boat.
    -Why an oil change (although not the worst thing in the world as I do it this time of year anyway).

    I plan to have them handle all the clean-up. No way I want to tackle that one.
  6. Capt Ralph

    Capt Ralph Senior Member

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    -Why a possible insurance claim
    This is above and beyond a service issue. This is hazardous material and may threaten your life.
    If you sell the boat in the future, any of the new family gets sick, it may come back to you personally for not properly cleaning it up.

    -Why an oil change
    Your engine just digested that soot suspended in the intake air. Dirty oil will not clean the valve guides and piston rings well, I'ts already full of micro thingies.
    Clean oil can absorb and clean these engine components a lil better.

    You also may investigate new turbos. Or having yours serviced and cleaned.
    Can't clean them on the engine, that would just wash more soot into the engine.

    So many things to consider, this is why at least get a proper surveyor involved quickly.
  7. Capt J

    Capt J Senior Member

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    Aside from what everyone else said. Have the other engine exhaust checked thoroughly as 20 years is a long time on an exhaust system and problem time for it to be replaced.
  8. Capt Ralph

    Capt Ralph Senior Member

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    Really good thought here also.
  9. Prospective

    Prospective Senior Member

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    Hey all. Just closing the loop on this one. Inspected by mechanic and no surprises. Flange of exhaust elbow that connects to turbo broke off. So having elbows on both motors replaced. Volvo parts prices are $$$ as everyone knows so not a cheap date when you add in cost of engine room clean up. Thankfully no damage to turbos. Also doing air filters, breather filters, and oil change. That stuff was basically due so no big deal there. Honestly, I try to stay on top of maintenance and service intervals but I never knew exhaust elbows were essentially a wear item that should be replaced periodically. No sign of wear on exterior so only way to know would have been to pull and inspect them. Always learning...
  10. NYCAP123

    NYCAP123 Senior Member

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    When ours blew the trouble brewing was evident when I inspected the engine room. Rust and corrosion around the bolts. Did you check with your insurance company? I'm very curious (skeptical) about what if anything they'll cover.
  11. Capt Ralph

    Capt Ralph Senior Member

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    Some yes.
    Some maybe not?
    Mine are 42 years old.

    Wet elbows, mixers, risers, dump cans, shower head and more names are made from different materials.
    Of all the crazy failures that I have heard of, it has been a rust or corrosion issue. Not just a ring breaking off.

    Could you please post some pictures?
  12. Prospective

    Prospective Senior Member

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    I suspect the rust and corrosion had been covered over by paint...

    No I did not check with my insurance company. Was thinking it's simply a mechanical failure of a wear item. Didn't think it was worth it. Also figured it might slow the repair as they'll want to send out a surveyor/adjuster, likely to tell me I'm not covered. But perhaps it's worth it.

    **EDIT... update to say I talked to my insurance co. I have a pretty high deductible so not worth a claim.
    Last edited: Sep 14, 2020
  13. Prospective

    Prospective Senior Member

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    I don't have any pics. But I saw the part in the vice at the yard this AM. Mechanic showed me where a flange was "supposed to be" on the elbow that had broken off. Apparently that mates to a matching flange on the turbo and is then clamped together with a part that volvo calls a "V Band Clamp". I suspect the reason this part broke is related to vibration. Not only is it likely 20 years old and likely corroded... but, as I mentioned in the original post... at the end of last season I noticed that a band that clamps around the riser and attaches to a stainless strut to stabilize the elbow had broken. I replaced it at the beginning of this season but not sure how long it was broken before I noticed it. So elbow may have been subject to more vibration and weight then was good for it for some period of time.
  14. Capt J

    Capt J Senior Member

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    Check your motor mounts extremely well also, because the motor can be moving around more than normal and that can create excess torque on the exhaust.
  15. Capt Ralph

    Capt Ralph Senior Member

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    On a boat where propulsion & generators machinery with toxic exhaust, mix with our guest and luved ones, I kind of get carried aweigh when all of the above is pressed into a boat.
    It was not a claim for the failed part I was intending for your insurance to be concerned with, just the exposure to poisonous gases and chemicals tossed thru and near to so many boat systems including the people AND the popper clean up.
  16. NYCAP123

    NYCAP123 Senior Member

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    Probably correct. I suspect that if anything they might cover the cleanup cost only which they'd easily recoup in a premium increase unless you brought in a hazmat crew as Ralph suggested. Besides, as much of a PITA cleanup is it's something I'd rather do myself.
    Last edited: Sep 14, 2020
  17. NYCAP123

    NYCAP123 Senior Member

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    This is a good lesson for owner-operators who think owning a boat is like owning a car. Most barely do engine room checks if at all. I always try to impress on them that they've got the systems of 2 tractor trailers and a house with the added stressors of extreme vibration and salt water. The one thing you don't check is the one that'll surely bite you.
  18. Fishtigua

    Fishtigua Senior Member

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    While in Monaco for the F1 race, a mate's 1962 yacht next-door had a cracked exhaust elbow. Right in the middle of the Grand Prix, I managed to solder a braze over the crack using just a propane torch and a wire coathanger. Lasted just the 20 miles it needed to get home.