04 390 Motoryacht

Discussion in 'Diesel Engines/Drives/Transmissions/Props' started by JM390, Nov 13, 2019.

  1. JM390

    JM390 New Member

    20
    Oct 1, 2019
    2003 Sea Ray 390 Motoryacht
    Cummins 480 CE
    Hey guys wondering what the cost for replace is per motor to due the heads. I had valve seat fail and drop and now need a new head and possibly piston. Is it doable to drop the pan in the boat and pull it? Seems like just enough room. This is a real bummer.
     
  2. BubbaFrsh

    BubbaFrsh Member GOLD Sponsor

    51
    Aug 22, 2009
    Tampa, Florida
    "SeaExec II"
    2005 420 Sundancer
    480 CE
    uggh, I have been following you story on sbmar. I proactively replaced both heads on mine last year and it cost me around 15k. My theory was replacing both prior to the valve seat failing would probably be cheaper than rebuilding one engine. Of course there was no damage done to mine when I replaced them. I am not sure but the damage of dropping the seat will probably increase the cost. I am still sorting through an overheating issue on one side, not sure if that is related to head replacement. Sorry to hear this news. If there is anything I can help with let me know.

    Matt
     
  3. JM390

    JM390 New Member

    20
    Oct 1, 2019
    2003 Sea Ray 390 Motoryacht
    Cummins 480 CE
    Thanks Matt.

    Where are you out of ? Who did the work ?

    I will definately be doing both motors. Just don’t know the severity of the damage beyond the head yet.

    I am considering contacting Cummins to discuss also because this generation head was supposed to have been the upgraded model. I have heard they will kick in on some things when it’s a known failure. I can’t believe this. I did my due diligence and sea trialed with 2 Cummins mechanics and both motors passed with flying colors. Really shocked.
     
  4. BubbaFrsh

    BubbaFrsh Member GOLD Sponsor

    51
    Aug 22, 2009
    Tampa, Florida
    "SeaExec II"
    2005 420 Sundancer
    480 CE
    I am out of Tampa, and I had Southeastern Marine Power do the work. I have another great mechanic who is actually friends with Tony that does most of my work, but this was a big project and he didn't want to tackle it. Down here the Cummins guys will not work on a boat and send you to southeastern or the boat dealer. (I find that very weird but that's been my experience)

    Contacting Cummins is worth a shot, I have heard that they have helped out some people when it fails. Mine had not failed so they weren't going to help me at all. Unfortunately, you can do all the due diligence in the world, but unless you know exactly how the previous owner ran the boat, you would never know. I guess unless you pulled the heads and looked. My Dad and I bought this ours with only 83 hours on it so it was like brand new. I knew after finding Tony's information that I had run it overloaded for a hundred hours or so. That was enough for me to bite the bullet last year and replace the heads. I have attached a copy of the Cummins service bulletin I found during my research.

    I have taken several inches of pitch out of my props and I am now slightly below the 450 curve as Tony suggests on the port and right at the 480 curve on the starboard. A difference of about a gallon an hour. I have no clue as to why such a difference. From what I am told since we have a hybrid engine, electrical governor and mechanical fuel pump, the fuel flow is based off several different factors like throttle position. I don't recall all the factors but I have been told they are pretty damn accurate. They were a lot closer prior to the head change, so I hope it has something to do with the change, I just need to figure out why.

    My current project is trying to figure out why one side is running hot even after having the complete cooling system service.

    The next project is the exhaust system. There is another time bomb I believe. At 14 years old, the risers probably need to be changed, and the design definitely needs to be improved. As you get in to this project, inspect the turbos carefully and make sure there is no signs of water intrusion. Tony has some great articles on exhaust design, and they all seem to make sense. Gravity can be your best friend or your worst enemy.

    Good luck on this project, I know it hurts. Wait until you see your baby all torn up, that really hurts. Once it is complete, you will once again have confidence in you powerplants. Contact me if you have any questions, and I will be glad to help out. Even if its just to have a someone to commiserate with about these damn boats we love so much.

    Matt (sorry I rambled a bit)
     

    Attached Files:

    JM390 likes this.
  5. BubbaFrsh

    BubbaFrsh Member GOLD Sponsor

    51
    Aug 22, 2009
    Tampa, Florida
    "SeaExec II"
    2005 420 Sundancer
    480 CE
  6. JM390

    JM390 New Member

    20
    Oct 1, 2019
    2003 Sea Ray 390 Motoryacht
    Cummins 480 CE
    Yup very aware. I had 2 Cummins certified mechanics on the boat for 4 hours during the sea trial shooting temperatures and checking everything while underway prior to purchasing the boat. everything checked out 100%. Fuel burn was close to the 450 curve. I am beggining to think maybe we ingested something and caused it to over heat. We did a hear a bang while driving and moments later the engine stumbled and died. I did see a over heat alarm come on right as it died. Ironically it also has a vibration on the star board side now too. So not sure yet but definately sure the valve seat dropped.
     
    Last edited: Nov 14, 2019
  7. craigswardmtb

    craigswardmtb Active Member

    143
    Jul 2, 2013
    Mystic, CT
    2004 420 DB
    2005 360 Fiesta Vee
    Cummins 6CTA
    Sorry to hear of your issues Josh. Never fun on a new boat that you thought was turn key. How are you making out with the repair?
     
  8. Carpediem44DB

    Carpediem44DB Well-Known Member PLATINUM Sponsor

    585
    Aug 18, 2015
    Sanfransico Bay area
    2006 44 DB Sedan Bridge Raymarine gs165 w Quantum HD Radar
    Achilles 350 Dink
    Nick Jackson Davit
    Cummins QSC 8.3 500 HD
    A real Bummer Josh, I posted about this very issue on my buddies 04 420 Sedan Bridge a couple of years ago. He just bought the boat and chose the boat because of its impeccable pedigree and condition. On his first weekend cruise out started engines to make the 40 + mile trip home and he dropped a seat.
    700 hrs on the engines. On the 420 there is not enough room under to engine to drop the pan so the STRD engine was removed for piston, rod and sleeve replacement. He went ahead and replaced the port engine head out of an abundance of caution as well. He also needed a Strbd Turbo as part of a valve went thru it. The bill came to about $32,000, the month before his slaes tax bill arrived! Harold contacted Cummins and they gave him the old "gee, we ain't never heard of this happening" which we knew was BS. Harold did not want to do the lawyer thing so he just ate it in the name of boating. Its stories like yours that remind me but for the grace of god go I. Any of us running these magnificent vessels live with the exposure that every time we hit that starter switch we could hear the big bang. Good luck with your repairs.
    Carpe Diem
     
    JM390 likes this.
  9. JM390

    JM390 New Member

    20
    Oct 1, 2019
    2003 Sea Ray 390 Motoryacht
    Cummins 480 CE
    Thanks Craig. So valve seat definately dropped but luckily ( maybe) not the valve. Damaged the head, minor to piston ( it appears) and maybe piston liner. I have been able to scope it and can see piston is still there but cant see really how much damage to piston if any.

    Right now going through the process with the insurance company to accept liability for a latency defect. We will see. Either way the port motor will need new head, piston probably, maybe liner and related components.

    Star board motor is fine but I am going to pull head and do it anyways to save me this later. Sucks!
     
  10. craigswardmtb

    craigswardmtb Active Member

    143
    Jul 2, 2013
    Mystic, CT
    2004 420 DB
    2005 360 Fiesta Vee
    Cummins 6CTA
    Good luck. Hopefully insurance steps up. I am also going through insurance issues to get them to replace my swim platform lift after storm damage. 20k'ish. Not fun...
     
  11. JM390

    JM390 New Member

    20
    Oct 1, 2019
    2003 Sea Ray 390 Motoryacht
    Cummins 480 CE
    Uggh that sucks man. Well lets keep the good vibes going for each other and get through this mess so we can go cruising in the summer!
     

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