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GM DETROIT DIESEL 12V71 TI

Discussion in 'Technical Discussion' started by scandé, Dec 26, 2017.

  1. scandé

    scandé Guest

    Hello
    I am going to buy a bertram 65 with two engines GM DETROIT DIESEL 12V71 TI
    I have no information about engines
    I would like to know the realistic consumption of diesel? ...
    Thank you for your answers
  2. Capt J

    Capt J Senior Member

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    At 1000 rpms they burn 6 gph each. At 1900 RPMS, around 40 GPH each. Providing vessel achieves 2300 RPM's WOT.
  3. rcrapps

    rcrapps Senior Member

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    We own a 58' Bertram with the TI's. 650HP tune.
    Are you sure you do not have the TA model @ 900 HP?
    Wet / dry turbo is the first thing easy to see what you have.

    At 1450rpm we average 10kts and 2 US Gallons per nautical mile. 1800rpm were doing almost 16kts at 3+ US gallons per mile. WOT; just under 2300rpm, 22+kts, just under or at 4 gallons per nautical mile
    Ad another 1 US gallon per hour average for the gen-set.

    They do use a lil bit more than the newer engines but not much more. Lots of us here at YF are DDC 71 fans.

    Bertram made manuals for all their boats with test run data (Light boat). Check the Bertram web site, the Bert 65 manual may still be available.
    The new owners did continue the Bertram web library.
  4. CaptOz

    CaptOz Member

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    Here are some GPH charts for the 12V71TI.

    at 1200 RPM you are burning 8gph and at 1900 you are at 30 gph. I have flow scans on my boat and that pretty darn close where I am at.

    Attached Files:

  5. Bill106

    Bill106 Senior Member

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    The boat in my signature picture originally had 900 hp 12V71TI's and at our normal 1950 rpm cruise was 32gph per side. They were some of the last factory 71's in the Penske era (1998), not aftermarket JT's or Covingtons. If I recall correctly they did end up with 12 hole 145 injectors but could have been 135's.
  6. CaptOz

    CaptOz Member

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    My boat came with BK Power 900Hp 12v71TI's that had 12v71TA 1080hp injectors . I have since detuned it back to Original Detroit Factory Spec. Less Fuel, Less Smoke.. but Less top speed.
  7. rcrapps

    rcrapps Senior Member

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    900hp TIs or TAs?
  8. CaptOz

    CaptOz Member

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    TI's
  9. Bill106

    Bill106 Senior Member

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    As many times as I changed kits in her (5!) I should have remembered the cooler was under the blower so TA's Ralph, sorry!
  10. Capt J

    Capt J Senior Member

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    I ran a set of Covington TI's which were 765hp. The chart posted is for only 70 Liter per hour injectors. The Covingtons I ran had 110 Liter per hour injectors but also ran a generator injector height, 1.46". It did the figures I posted, but it also ran crystal clean at ALL rpm points.
  11. rcrapps

    rcrapps Senior Member

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    I was scratching my head and about to dive into some research tonight. After living aboard for 13 years now, our ole Bert has gained some weight.
    I'm still looking for another 100hp out of our N90 / 650hp / TIs. I'd hate to mess with my new perfect factory wheels. Just need to pick up that missing umpa and <50 rpm on top.
    Have a lil problem crawling uphill on the swells also lately.
    Santa brought a new anchor windlass. New chain coming to replace the nylon.
    Yep, may need some of that fat injector stuff.
  12. rcrapps

    rcrapps Senior Member

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    Was that with the cams advanced? You remember the injector model number?
  13. Ormond Bert54

    Ormond Bert54 Senior Member

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    My 12V71 TI engines were overhauled recently. If they need to be done, pull them out and overhaul in the shop. Approx $45k each.

    The dyno horsepower is 860 hp @ 2300
    The Injectors are 9215 part R5229715
    The Turbos are R5101513
  14. rcrapps

    rcrapps Senior Member

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    Yep, 9215s, fuel pushers.
    thx, rc
  15. Capt J

    Capt J Senior Member

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    I'm guessing the cams were advanced because 2 different Detroit Diesel dealers INSISTED on setting the injectors at the marine height 1.96" and the motors black smoked so bad, you could not see 50' past the transom. I do not remember the injector number......but look in the DD book under Covington and 765hp and you can probably find it. I haven't dealt with that boat since 2012.
  16. scandé

    scandé Guest

    Oh
    thank you very much
  17. scandé

    scandé Guest

    hello and thank you for your information
    my engines
    12V71 TI DD12VA085387
    12V71 TI DD12VA085384
    J4AI CONTACT WITH THE SON OF MR BERTRAM
    THIS BERTRAM THE FLYINHG EAGLE
    WAS THE BOAT OF DICK BERTRAM IN 1973
    BUT BERTRAM COMPANY HAS MORE DOCUMENTATION
  18. rcrapps

    rcrapps Senior Member

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    Hello scandé
    When technical threads come up like this, Sometimes we get carried away and chat on some things not really related to your original post (op).
    I apologize for my side track of your thread.

    Hope your original question was answered.

    Keep asking 71 questions, those responding here live with and make a living on Detroit 71 boats. Many more 71 fans in YF.
  19. rcrapps

    rcrapps Senior Member

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    Serial numbers from 1977?

    Attached Files:

  20. scandé

    scandé Guest

    THANK YOU
    I CONTINUE MY INVESTIGATIONS

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