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  1. #1

    Default Yanmar 6LPA Turbo Fan surface rust

    2006 Yanmar 315 6LPA Turbo

    I would like to know what would cause the turbo exhaust side to get rusty?

    I needed to use a Cylinder Hone to hone down the surface rust so that the fan turned freely.

    Thanks
    Sam

  2. #2
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    Default Re: Yanmar 6LPA Turbo Fan surface rust

    Could be a sign that your exhaust setup is letting too much salty air/moisture back up the exhaust. Haven't had this with our 6LP's on shafts but had it a lot with some previous Volvo's on stern legs. You need to be super careful about what you remove as the clearances between the exhaust housing and vane tips will seriously reduce your boost if they get too big.

  3. #3

    Default Re: Yanmar 6LPA Turbo Fan surface rust

    Quote Originally Posted by aliboy View Post
    Could be a sign that your exhaust setup is letting too much salty air/moisture back up the exhaust. Haven't had this with our 6LP's on shafts but had it a lot with some previous Volvo's on stern legs. You need to be super careful about what you remove as the clearances between the exhaust housing and vane tips will seriously reduce your boost if they get too big.

    what should I check out?

    Thanks
    Sam

  4. #4
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    Default Re: Yanmar 6LPA Turbo Fan surface rust

    There will be a spec for the vane tip clearances on your turbo. First sign usually though is low boost meaning that you are making more black smoke than normal and can't reach your WOT RPM's and speeds. Are you on shafts or Stern Drive legs?

  5. #5

    Default Re: Yanmar 6LPA Turbo Fan surface rust

    Quote Originally Posted by aliboy View Post
    There will be a spec for the vane tip clearances on your turbo. First sign usually though is low boost meaning that you are making more black smoke than normal and can't reach your WOT RPM's and speeds. Are you on shafts or Stern Drive legs?
    My Turbo is a RHE6
    parts number
    119775-18010

    I do not have black smoke at all, maybe some white which I think is just moisture in the air?

    I do not know what that is?
    vane tip clearances


    My RPM and speed all seem fine?

    I have a jack-shaft with Merc Bravo 3 out-drive double prop.

    Thanks
    Sam

  6. #6
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    Default Re: Yanmar 6LPA Turbo Fan surface rust

    There is a specification for the maximum gap between the ends of the exhaust compressor vanes (tips) and the exhaust housing that they spin in where you removed the rust. I don't have it for your turbo but if you are making your WOT rpm's and speed without black smoking then it is probably all OK. The issue with some outdrive setups is that you can get a lot of moisture back up into the exhaust housing and hence the turbos can rust more quickly. Quite a few turbo diesel marine engines get a bit of this going on as they age but it depends a lot on the way the exhaust is setup and the riser/elbow design etc. For you it might just be one of those maintenance things you need to do occasionally but the trick is to remove as little rust as you can so you don't make the vane tip clearances so big that you lose boost.

  7. #7

    Default Re: Yanmar 6LPA Turbo Fan surface rust

    Quote Originally Posted by aliboy View Post
    There is a specification for the maximum gap between the ends of the exhaust compressor vanes (tips) and the exhaust housing that they spin in where you removed the rust. I don't have it for your turbo but if you are making your WOT rpm's and speed without black smoking then it is probably all OK. The issue with some outdrive setups is that you can get a lot of moisture back up into the exhaust housing and hence the turbos can rust more quickly. Quite a few turbo diesel marine engines get a bit of this going on as they age but it depends a lot on the way the exhaust is setup and the riser/elbow design etc. For you it might just be one of those maintenance things you need to do occasionally but the trick is to remove as little rust as you can so you don't make the vane tip clearances so big that you lose boost.
    When you say turbo vaines, I think you are talking about the blades that look like fan blades? right?

    if so when I used the cylinder hone, I just gave it a few spins, until it knocked off some of the rust blisters.

    The last time I did this was last spring, I removed the exhaust housing last week just to see if the blades were spinning freely. and they were and it still looked OK inside.

    The first time I had the rust and carbon buildup, my boat did not get on plain. that's when I first checked into the problem. The turbo vaines did not have any movement. so when I removed the turbo from the housing, I honed it down a bit. So I have been keeping an eye on it.

    I made this post to see if there was anything that I could do to prevent this from happening?

    Thanks for your response.

    Sam

  8. #8
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    Default Re: Yanmar 6LPA Turbo Fan surface rust

    Yes vanes = fan blades

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