CAT 3116 the good or bad engine ?

Discussion in 'Diesel Engines/Drives/Transmissions/Props' started by SEAWOLF, Dec 8, 2021.

  1. SEAWOLF

    SEAWOLF Member

    48
    Nov 15, 2020
    New Jersey
    1998 Sea Ray 330 Amberjack EC
    Horizon 7.4 MPI'
    Hi All
    My friend looking at Sea Ray boat with Cat 3116 300 HP engine . Need real world inside.
     
  2. mrsrobinson

    mrsrobinson Well-Known Member SILVER Sponsor

    Mar 9, 2006
    USA
    N/A
    N/A
  3. yobub

    yobub Well-Known Member PLATINUM Sponsor

    771
    Jul 29, 2016
    Northern Illinois
    1998 400 Sundancer
    Cat 3116's
    @SEAWOLF 1998 3116's 350hp. Owned them for 4 years, very happy so far. Approx 1700 hours.

    Many of us own these, many will chime in. Keep the fuel clean, don't let the engines overheat, change your oil and filters, and they run. Depending on the age, there is a major service at 2000 hours to be aware of.

    Would buy a boat with these again with no question.
     
    dtfeld likes this.
  4. carterchapman

    carterchapman Well-Known Member TECHNICAL Contributor SILVER Sponsor

    Mar 25, 2008
    Lake Chickamauga/Marietta, GA/Ft. Myers, FL
    2006 Sea Ray 58 DB
    MAN CRM V8-900s, Twin Disc Drives; Onan 21.5 Generator
    +1
     
  5. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives
    Great Engine period.

    +2
     
  6. GnrlPatton

    GnrlPatton Active Member PLATINUM Sponsor

    473
    Jul 12, 2010
    Maple Valley, WA
    Current: 1998 370 Express Cruiser
    Sold:1988 230 Weekender
    Twin Cat 3116T
    What he said ^^^
     
  7. Jus the two of us

    Jus the two of us Active Member

    273
    Dec 7, 2015
    United States Lake Cumberland
    1998 Sundancer 450
    2009 Sundancer 55
    3116 Cats
    MAN 900
    +3
     
  8. Strecker25

    Strecker25 Well-Known Member PLATINUM Sponsor

    Nov 20, 2014
    Rochester, NY
    2002 410DA
    Caterpillar 350HP 3126
    first diesel engines for us, similar to the 3116 but we have 3126. Absolutely love them, the power, efficiency, sound and smell (personal preference ;) ), etc.
     
  9. mrsrobinson

    mrsrobinson Well-Known Member SILVER Sponsor

    Mar 9, 2006
    USA
    N/A
    N/A
    I notice the OP said 300HP, folks are replying with 350HP though. Typo by the OP?
     
  10. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    The 300 hp and the 350 hp 3116's are almost identical except for fuel pump and injector settings and perhaps the turbo charger.

    The 3116 's are very low maintenance engines. There are very few recommended procedures……@250 hours, reset the engine overheads- takes about 8 hours; @ 1000 hours have the after-coolers and heat exchangers cleaned cost varies depending upon how the technician cleaned the heat exchangers; @ 2000 hours, reset the overheads and clean the after-coolers and heat exchangers, again about 8 hours, plus the cost of the after-cooler service which will vary depending upon how the technician cleaned the heat exchangers.

    Depending upon which Sea Ray your friend is contemplating, the boat could be a bit underpowered with 300hp engines. If that is the case, then be sure they turn up to 2800 rpm at WOT and don't cruise the engines at more them 2400 rpm, which is recommended cruise speed for the 3116. If they won't turn up to 2800 rpm, then limit your cruise speed to 86% of the WOT the engines will develop, until you either lighten the load or have the props re-pitched.

    All in all, these are nearly bullet proof engines as long as you don't not over heat or overload them.
     
  11. ttmott

    ttmott PhD in OCD TECHNICAL Contributor GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    I didn't know SR installed any 300HP's; thought they were all 350. Learn something every day.
     
    mrsrobinson likes this.
  12. mrsrobinson

    mrsrobinson Well-Known Member SILVER Sponsor

    Mar 9, 2006
    USA
    N/A
    N/A
    "And don't Cruise the engines at more than 2,400 rpm"

    This is what kept me from buying a friend's 1998 400da with twin cats. He used to brag how hard he ran the boat. Plus they had over 2,000 hours with no service history at all other than his word.

    I know you can pull these rpm numbers off of a gas engine (how many hours at what RPM range), can you pull them off of these cats? If you can't how do you know you're buying a boat where the owners kept to this?
     
  13. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives
    Most if not all the CATs of that era are mechanic diesels, no electronics so you cant "pull" the history. The only way to tell anything is to have them surveyed by CAT. In the end these either run or they do not run, not much in between.

    Not sure what "hard" is, but these are pretty robust engines. CAT expects these 3100 engines to be run at WOT at least some of the time, I think the E spec is 8% of the time, so 5 minutes out of every hour, and the engine hours to be somewhere between 250 and 1000 annually. Not many of us are even getting close to that. These are likely 10,000 ++ hour engines if well cared for. They don't like being run at idle speed for long periods either.

    Make sure they are not over propped then...Start 'em up, warm 'em up, and run them. Spend the majority of the time at a reasonable cruise RPM (2000-2400, CAT recommends 2400), but also at WOT if the situation dictates (within reason).

    I think about the only way to abuse these engines would be to run them WOT all the time every time out, but I cant imagine any reasonable owners doing this as the fuel economy would suffer horribly, negating one of the major reasons to own a diesel boat.
     
    Last edited: Dec 9, 2021
  14. mrsrobinson

    mrsrobinson Well-Known Member SILVER Sponsor

    Mar 9, 2006
    USA
    N/A
    N/A
    Hard means he ran pretty much at WOT all the time.
     
    dtfeld likes this.
  15. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives
    That’s not just hard, that’s just plain dumb.

    Even with that, the engine is probably fine, but the longevity will be decreased, and more MX required. If that info is known, you a right to steer clear.

    With that said, running a diesel “easy” can have the same deadly effects.

    https://boattest.com/article/how-long-will-my-engine-last
     
    mrsrobinson likes this.
  16. Saverio

    Saverio Well-Known Member

    Aug 31, 2010
    Long island new york
    1995 450 DA
    Cat 3126 420hp
    900 hours Westerbeek Generator
    how would you know if your over propped? you cant reach wot?
     
    dtfeld likes this.
  17. dtfeld

    dtfeld Water Contrails GOLD Sponsor

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    12" Axiom and 9" Axiom+ MFD
    Cat 3126 V-Drives
    Correct. Especially with the older mechanical diesels. Typically you want them to spin up to the rated RPM +25 to 50 as you run the boat, fuel water people gear etc with a clean bottom good props. Thats 2800-2850 for the 3100 CATs. The Cummins also have a specific fuel burn to be under to prolong the life of the engine.

    If you're a member on boatdiesel.com, there is a prop calculator that allows you to crank in your boats engine/transmission/weight and WOT readings (must be accurate, don’t trust stock SR tachs), and it will give you a curve of how much you are over or under propped. Ideal is right on the curve…not lugging the engine, and also not wasting fuel if under propped.

    SBmar.com has lots of information on the Cummins side of things.
     
    Last edited: Dec 14, 2021
  18. ttmott

    ttmott PhD in OCD TECHNICAL Contributor GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    Or see what your boat pulls then take the props to your prop shop and tell then you need XX more RPM and they know what to to.
     
  19. Saverio

    Saverio Well-Known Member

    Aug 31, 2010
    Long island new york
    1995 450 DA
    Cat 3126 420hp
    900 hours Westerbeek Generator
    I had my props cleaned and tweaked. I couldn't go over 2650. now I'm at 2850 with the sync on. I was thinking of maybe pitch it one degree or have them cupped
     
  20. The Bill Collector

    The Bill Collector Well-Known Member GOLD Sponsor

    Jun 2, 2008
    Tacoma, WA
    1998 450 Sundancer, Achilles dinghy w/15hp
    3126 Cat's
    FYI, when on the sync on my boat, at WOT the sync kicks off and it's a hard turn...
     

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