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Wastegate valves on diesel engines

Discussion in 'Technical Discussion' started by CSkipR, Dec 9, 2015.

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  1. CSkipR, Dec 9, 2015
    #1
    CSkipR

    CSkipR Member

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    Is it possible that wastegate valves on Man engines can cause the diesel engine to produce soot? If this can cause soot can wastegates be repaired or do they have to be replaced?
  2. Marmot, Dec 10, 2015
    #2
    Marmot

    Marmot Senior Member

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    In a roundabout way ...

    If the wastegate is leaking badly the turbocharger will not recover as much energy from the reduced exhaust flow. This means that charge air flow is also reduced and that reduces the power output at which smoke point is reached.

    You don't say which engine model it is so it is impossible to go much further with the information available. Talk to a dealer or shop that works with those engines.
  3. CSkipR, Dec 10, 2015
    #3
    CSkipR

    CSkipR Member

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    Marmot,
    The engines are Man CR900 V8 made in 2005. Will post a picture of them.
    Skip
  4. Marmot, Dec 10, 2015
    #4
    Marmot

    Marmot Senior Member

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    Thanks. Those engines have a boost control system that uses the waste gate to bleed off exhaust now the question is, is the wastegate actually leaking or is the boost control system malfunctioning?

    Do you think the wastegate is leaking because boost is low?

    I think it might be more productive to have a MAN tech look at the engine and determine if anything is out of spec before throwing parts at the engine or taking things apart.
  5. CSkipR, Dec 10, 2015
    #5
    CSkipR

    CSkipR Member

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    Here is a picture of the one on the port engine inside. IMG_1880.JPG IMG_1880.JPG

    Attached Files:

  6. CSkipR, Dec 10, 2015
    #6
    CSkipR

    CSkipR Member

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    Wondering if the spring inside gets stuck in the open position would this create extra soot?
    Since you mentioned the charge air flow I believe that is shown on my Man instrument although not sure what the correct reading should be. Its not enough to set off an alarm.
  7. Capt Ralph, Dec 10, 2015
    #7
    Capt Ralph

    Capt Ralph Senior Member

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    I can't remember from your previous post, What boost readings are you getting on the display?
  8. CSkipR, Dec 10, 2015
    #8
    CSkipR

    CSkipR Member

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    Charge air is approx. 97 when cruising at 1950rpm. Believe turbo boost is 24/25 at same rpm.
  9. Capt Ralph, Dec 10, 2015
    #9
    Capt Ralph

    Capt Ralph Senior Member

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    Same on both engines?
  10. CSkipR, Dec 10, 2015
    #10
    CSkipR

    CSkipR Member

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    Yes pretty close.
  11. Capt Ralph, Dec 10, 2015
    #11
    Capt Ralph

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    Close the hatch and walk away with a smile.
  12. CSkipR, Dec 10, 2015
    #12
    CSkipR

    CSkipR Member

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    I can't too much soot. Ran back from Palm Beach to Ponce this week (intracoastal) after new paint job and had too much soot for common rail engines. Got to find issue its very frustrating.
  13. Capt J, Dec 10, 2015
    #13
    Capt J

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    Those are right (boost, air inlet temp) where they should be. Yes, MAN has had issues with the waste gates on your style diesel, but your motors are not experiencing that and it's not your issue. How many hours are currently on your engines? Have you had the valves adjusted, injectors and or nozzles checked, I think yours has nozzles, fuel injector pump checked? Usually on MAN's around 1000 hours the injector pump will make them smoke more and it's supposed to be check along with injectors or nozzles. Valve adjustment is supposed to be done at 800 hours. Have the aftercoolers ever been cleaned? That should be done every 1000 hours or sooner (MAN calls for 1000 hours or every 2 years, nobody ever does them every 2 years). What's your air inlet pressure? You should see less than 5? Dirty/restricted air filters will also cause smoking. Does yours have paper ones or washable? If washable and over 10 years old, and crushed looking, replace them.
  14. CSkipR, Dec 10, 2015
    #14
    CSkipR

    CSkipR Member

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    Capt J,
    Hours 1125. Valves were adjusted at 400 and 1000 hr. Injectors and nozzles not checked since it is not called for on their inspections. The fuel injector pump as not been checked that I'm aware of. The aftercoolers were cleaned at 1000hrs. Will have to check on air inlet pressure but pretty sure it is around 2 or 3. The air filters are washable and cleaned annually although haven't changed them in 3 -4 yrs. They aren't crushed.
  15. Marmot, Dec 11, 2015
    #15
    Marmot

    Marmot Senior Member

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    All the above is precisely why you should have a MAN tech verify the engines are operating within tolerances. Unless you have a way to connect your engines to your router so a tech can access the data all anyone can do on the internet is point in a lot of different directions.

    It is beginning to sound like nothing may be wrong. The amount of soot staining and its appearance, particularly after a new paint job, is highly subjective and it might be a case that the same amount of soot is just more visible. Just for the sake of discussion, if we are to assume your engines meet the EPA emissions standards for 2006 and are running at 50 percent power in test cell perfect conditions they may be exhausting about a half ounce of soot and other particulates every hour, probably considerably more in real life conditions. That is the nature of the beast and nothing other than exhaust post treatment can change that.

    It might be worth testing the fuel for quality and sulfur content before calling in the pros. Have you loaded fuel in the Bahamas recently? If you did there is a good chance that it was not ULSD (regardless of what the bunker ticket says) and particulate emissions increase substantially with sulfur content.
  16. CSkipR, Dec 11, 2015
    #16
    CSkipR

    CSkipR Member

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    Marmot,
    I do understand that I may need to have Man tech check out. Unfortunately there are none close by so just trying to have more knowledge before reaching out to them. Prefer not to find issue by process of elimination, if possible.

    The soot issue did not just start it has been an issue for a long time. Paint job didn't make any difference. Always visible all over back of transom, cockpit, door, bridge, etc.

    In my opinion I don't think the engines are running at EPA standards for 2006 based on several boats that I've been on with the same year model and engines.

    Fuel is fine and haven't been to the Bahamas since early summer. Gone through a couple of tanks since.
    Thx, Skip
  17. Capt J, Dec 11, 2015
    #17
    Capt J

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    What rpm's do the engines reach at WOT, if the boat is a little overpropped, it will cause them to run a little sootier than normal at cruise speed. But, I agree with Marmot that it might be time to call in a MAN tech with his laptop. Since you've done valve adjustment/aftercooler/air filters are clean/boost is where it should be. What's your fuel pressure when running at cruise? Man common rails normally run 70-86 psi fuel pressure. The only thing that comes to mind for me is fuel delivery (injectors or etc.) or slightly overpropped.
  18. CSkipR, Dec 11, 2015
    #18
    CSkipR

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    Capt J,
    With clean bottom and fully loaded turning 2355.
    Thx, Skip
  19. Capt J, Dec 11, 2015
    #19
    Capt J

    Capt J Senior Member

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    Providing you have the proper fuel pressure and not dirty fuel filters, it's really pointing to injectors. Everything else appears right. Do both motors smoke equally or is one smoking more than the other? Do you notice any weird sheen on the water coming out of the exhaust at idle at the dock? Any smoke on cold startup while it's warming up? Visually how bad is the smoke on a scale of 1-10?
  20. CSkipR, Dec 11, 2015
    #20
    CSkipR

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    Filters were just changed and this has been an ongoing issue even with new filters. Both motors appear to smoke about the same. Worst time is from idle ramping up to cruise speed. When running not noticeable to any extent. example: coming back from Palm Beach to Ponce and having to come off plane for boats, etc really made a sooty mess. Scale of 1-10 6-7
    No sheen on water. On startup a little smoke just for a few seconds.
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