Official Cummins 6cta 450C thread

Discussion in 'Diesel Engines/Drives/Transmissions/Props' started by FeLizDream, Apr 24, 2016.

  1. LMBoat

    LMBoat Member

    432
    Oct 4, 2006
    Ft Lauderdale
    1999 450 EB
    Cummins 6CTA's
    I do hear it, but it sounds like an external rattle. ck to be sure your remote oil filter is tight, then all the other stuff that is bolted to the outside of the engine.
     
    scooper321 likes this.
  2. my3sons

    my3sons Well-Known Member SILVER Sponsor

    Feb 24, 2009
    NY (Lake Erie)
    2004 400DB, Onan 9 kw Gen, Highfield RIB,
    Cummins 6CTA
    Jaybeaux, Don’t need a special tool for tdc.
    Valve clearances are 12 and 24 thousandths. So for a .012, the .012 fits with some resistance. .013 wont go.
    Complete instructions are in the owners manual. Should not need new gaskets.
    As others have said, it’s really easy but if you’ve never done it, there’s always concern. I show others how to do it and the response is always “really, it’s that easy?”
     
    Last edited: Oct 19, 2019
    Jaybeaux likes this.
  3. PMC

    PMC Well-Known Member

    Apr 10, 2009
    Long Island, NY
    2001 40 Sedan Bridge
    Cummins 6CTA
    A few tips for the shady tree mechanics with valve timing.

    There is a onboard pin on the front of the engine to locate TDC. It is plastic, and not designed to HOLD, so do not force the engine when inserted.

    You will not be able to "bar over" the engine on the crankshaft, but can using the alternator pulley.

    The specs for valve clearance is printed on the engine tag, specific for your engine.
     
  4. Irie308

    Irie308 Well-Known Member SILVER Sponsor

    May 28, 2013
    CT
    2004 420 Sedan Bridge, GHS Hydraulic Lift
    Dual Raymarine E120W
    AB Mares 10 VSX with 30 hp Tohatsu
    Cummins 450C 8.3 L Turbocharged
    More obvious when I listen with stero headphones . You can definitely hear a pronounced rattle.
     
    scooper321 likes this.
  5. NotHerDecision

    NotHerDecision Well-Known Member PLATINUM Sponsor

    Jun 28, 2016
    Houston, Texas
    2001 Sea Ray 460 Sundancer
    2014 Seadoo 155 LTD
    2105 Seadoo 130 SE
    2013 Mercury Dinghy
    Cummins 6CTA 8.3L
    Steve

    it does sound like valves to me. I would change the tensioner as well
     
    scooper321 likes this.
  6. scooper321

    scooper321 Well-Known Member GOLD Sponsor

    915
    Jul 4, 2015
    Baltimore, MD
    2003 Sea Ray 400DB
    Twin Cummins 6CTA-8.3
    Yeah, well it bothers me enough that I called a tech in for this one. One that knows my engines well. I’ll let you know what we learn on Friday.
     
    my3sons likes this.
  7. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    Ok. I hope I am done. I bought the boat in late 2013. That's at the end if it's 13th season. I didn't know enough to know at the time, but just about all the bolt ons to the engines were at or near end of life. Since purchase I have:

    Replaced seawater pumps
    Pressure tested heat exchangers
    Replaced aftercoolers
    Replaced gear oil coolers
    Rebuilt both turbos
    Replaced wet exhaust mixers
    Replaced exhaust hoses/elbows
    Replaced all seawater hoses
    Replaced all clamps
    Replaced aft seawater pipes
    Removed air grid heater circuitry
    Removed fuel coolers
    Replaced port alternator
    Adjusted valve lash
    Tuned props to 22.7 pitch
     
    Last edited: Oct 23, 2019
    Jaybeaux and carterchapman like this.
  8. Blueone

    Blueone Well-Known Member GOLD Sponsor

    Jan 24, 2007
    Lake Erie, Ohio
    2004 420 Sundancer
    Cummins 6CTA 450's
    How many hours did the major items have on them?... I know salt water will speed things up, was just curious
     
  9. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    The boat had about 1050 hours on it when I bought it. It now has 1900 hours. It has been a southeast salt boat it's entire life.
     
  10. scooper321

    scooper321 Well-Known Member GOLD Sponsor

    915
    Jul 4, 2015
    Baltimore, MD
    2003 Sea Ray 400DB
    Twin Cummins 6CTA-8.3
    As it turns out, this was a total non-issue. The engine is running great. The rattling I heard was not the valves at all but a loose lower bolt on the oil filter bracket. It was intermittent and didn’t rattle all the time and sometimes disappeared with increased RPM. And it wasn’t so loose that you’d feel it if you touched the filter. But that’s what it was. I feel I could have found this, so I’m a little humbled by this. And annoyed – I think I would have found this in another month when I changed my oil! Oh well, I got to chat with the tech about my tachs (he verified they were spot on – which means I need a slight re-propping) and we discussed changing the oil pressure sender on the port engine (ugh) and winterization. But no problems with the valves or the innards of the engine. Whew!

    And thanks for all the tips. I'm going to look back into the service records and see when the valves and tensioners were last worked on...
     
    my3sons and Woody like this.
  11. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    Great news. I have worked on that sender. Easy to get to from above. I had no problem. Of course I don't have all the air heater crap in the way anymore. My bouncing gauge turned out to be a failed ring connector on the wire end at the sender. Not the sender itself.

    also, several of us have found that once the valves are adjusted the first time, they stay pretty stable from then on. If you find they have been done, you may be in good shape.
     
    scooper321 likes this.
  12. Irie308

    Irie308 Well-Known Member SILVER Sponsor

    May 28, 2013
    CT
    2004 420 Sedan Bridge, GHS Hydraulic Lift
    Dual Raymarine E120W
    AB Mares 10 VSX with 30 hp Tohatsu
    Cummins 450C 8.3 L Turbocharged
    Phew....faith restored in the 450C! Let me know how the oil pressure sender replacement goes. I replaced mine but now the gauge spikes. I have to try to ground it somewhere else to see if that fixes it. But glad it was a non issue.
     
    Last edited: Oct 25, 2019
    scooper321 likes this.
  13. scooper321

    scooper321 Well-Known Member GOLD Sponsor

    915
    Jul 4, 2015
    Baltimore, MD
    2003 Sea Ray 400DB
    Twin Cummins 6CTA-8.3
    The sender diagnosis is going to be delayed. From looking at the SB engine, I know I can get to the sender, check the wire or even replace it, from above. Unfortunately, to do so I need to talk out the sofa so that I can fully open the port hatch. That's not happening until I'm done using the boat for the season. And it might wait until spring, when I have to remove the sofa to open up to get someone to change the impeller on that side and do the AC and HE cleans.
     
  14. Jaybeaux

    Jaybeaux Well-Known Member SILVER Sponsor

    661
    Jan 3, 2016
    Upper Potomac River
    420 Sundancer 2004
    Naught On Call
    Cummins 6CTA-8.3's with V-Drives
    9KW Onan Genset
    The topic is serpentine belts. I just completed 2 years on my belts, a bit over 150 running hours. It helps me sleep knowing that it is time to change them. I keep old ones as emergency spares.

    I just received an email from Diesel Parts Direct, from whom I have purchased parts. They are offering free shipping as their latest marketing gimmic. Shipping charges last time was $16+.

    A search on my belt, part # 3288812, shows 2 options: Genuine Cummins @ $67.59 each; and and after market for $50.58. See link: https://www.dieselpartsdirect.com/search?q=3288812

    This is the first time I remember seeing the after-market flavor on this site. Would you use it? Or am I being penny wise and pound foolish? Thoughts?

    Jaybeaux
     
  15. Blueone

    Blueone Well-Known Member GOLD Sponsor

    Jan 24, 2007
    Lake Erie, Ohio
    2004 420 Sundancer
    Cummins 6CTA 450's
    A lot of times the same manufacturer makes both... but more often it's cheaper because it is cheap. If you cant figure out who made the aftermarket belt I would stick with Cummins
     
    Jaybeaux likes this.
  16. hottoddie

    hottoddie Well-Known Member

    Jan 11, 2012
    Boston/Cape Cod
    1986 Sea Ray 390 EC
    Garmin 4212 Chartplotter
    Garmin 24 HD Radar
    Garmin 546s Plotter
    454 Crusaders
    That is beautiful work. You could not pay someone to do that quality work!
     
  17. NotHerDecision

    NotHerDecision Well-Known Member PLATINUM Sponsor

    Jun 28, 2016
    Houston, Texas
    2001 Sea Ray 460 Sundancer
    2014 Seadoo 155 LTD
    2105 Seadoo 130 SE
    2013 Mercury Dinghy
    Cummins 6CTA 8.3L
    Sorry for the confusion. I am attempting to get the pictures to upload correctly.

    Anyway, we painted the engines, rebuilt the turbos, replaced all hoses, powercoated the aftercoolers, elbows, and piping. Also replaced wire loom and zipties. Just generally freshened everything up.

    I still have the Genset to do as well as paint the turbos with Ceremic high heat paint and replace the fuel coolers which I also had powercoated.

    For reference I used Rust-Oleum Canvas White paint with some Majic hardener added. I handpainted everthing after wire brushing and treating with Ospho.

    There are 6 engine room lights which are Lumitec Ibiza and there is such thing as "wire loom tape" which is absolutely amazing and available on Amazon.

    The after bilge under the Genset is painted with Interlux Bilge Kote Gray and I plan to expand this once I finish he other detail work back there.

    Lastly, I have a local friend who made the decals on the engines so they all look nice and new as well for a final touch.


    If you see anything out of the ordinary feel free to let me know.

    478CD3C4-A384-4BF3-A4BA-9044564622D0.jpeg D3E1AFA6-A9A7-4BDE-ABFF-2DCD9FBD48FF.jpeg 940E2498-8B03-4AAD-A3AF-0E6A569A4F07.jpeg 422771C3-8D19-4235-BBA5-B63E2BA3F071.jpeg E5F20589-348A-4AE0-86E0-AD2CD11DF61C.jpeg 1AB4E876-040D-474C-9B25-B0E17B740447.jpeg B8A50514-8774-40C7-8D73-4E67903E42D5.jpeg 3F7DAA29-C207-42BB-A766-6966A78F6711.jpeg 87A097DB-9098-4AD7-B2F4-E475D05D55E6.jpeg
     
    Last edited: Nov 5, 2019
    Jaws, gmacd81, my3sons and 1 other person like this.
  18. Joint Custody

    Joint Custody Active Member PLATINUM Sponsor

    283
    Sep 20, 2017
    Lake Powell Utah
    2001 460 Sundancer
    Twin Cummins 6CTA8

    That is boat porn at its best!

    Looks really good.
     
    gmacd81 likes this.
  19. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    Way to make us all look bad Josh.

    What's with the 245 hrs on 9/14/19. Is that all the hours the boat had when you bought it?
     
    gmacd81 likes this.
  20. NotHerDecision

    NotHerDecision Well-Known Member PLATINUM Sponsor

    Jun 28, 2016
    Houston, Texas
    2001 Sea Ray 460 Sundancer
    2014 Seadoo 155 LTD
    2105 Seadoo 130 SE
    2013 Mercury Dinghy
    Cummins 6CTA 8.3L
    No that's the "Shown" hours not the "true" since I replaced the Tachs. I keep the actual Hours in my logs. I'm not making you look bad, just giving you inspiration!
     

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