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Caterpillar C7 Engine info?

Discussion in 'Engines' started by brianwill, Apr 17, 2004.

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  1. brianwill

    brianwill New Member

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    Does anyone have any information on the new Cat C7 marine engine? I heard it was on display at the Miami Boat Show but there's nothing posted at www.cat-marine.com.

    Thanks.
  2. diesel

    diesel New Member

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    I currently work for a combo CAT, MAN, MTU, DDC, Yanmar, Volvo shop. Is there a certain concern with CAT you would like to know?You must be specific. Did I spell that correctly? Anyhoo, the CAT C7 is a very new engine despite it roots so I cannot say good or bad about this engine. All I can say is that so far, CAT is very good for warranty.
  3. brianwill

    brianwill New Member

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    It's a potential candidate at some future point for a repower project, so I wanted to get a spec sheet on it. I was surprised to find all of the info on the new Cummins Quantum engines online, but nothing on the Cat C7 even though it's been displayed in public. The C9 engine specs are already online.

    Sorry for the very broad question, but do you have any overall impressions of these manufacturers with regards to their new offerings (e.g., common rail vs. electronic hydraulic injectors)?
  4. YachtForums

    YachtForums Administrator

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    I agree whole-heartedly with "diesel's" statement regarding CAT warranty. They REALLY stand behind their engines. I've heard this from quite a number of CAT owners over the years.
  5. diesel

    diesel New Member

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    By all means go common rail. The control and flexibility are unparalleled(did I spell that one correctly?). Seriously though, common rail offers many advantages over previous designs. If you tell me what boat you have, the speed you wan't to go and a general power rating you wan't to achieve, I will give you my recomendation, for what it's worth.
  6. brianwill

    brianwill New Member

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    I've got a Maxum 4600 SCB. She's 46' long, 14' 4" beam and 32,000 lbs. I spec'd her with the twin gas powerplant option for a few reasons:
    1. Boating on a Texas lake, while large, you just don't get the cruising time / engine hours (only 175 hrs. in almost 6 years)
    2. When I bought her, I was reading about the diesel emission requirements for 2006 and the exciting new technologies that would be required to meet them--now coming to market.
    3. Most mechanics down here clap their hands when they see a couple of Chevy 502 engines, and scratch their heads when they see a white-painted diesel
    4. My wife turns green after whiffing diesel exhaust, so I figured it would be better to wait for the new technology with less smoke, lower emissions, etc.
  7. brianwill

    brianwill New Member

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    Also, I'm pretty sure that you got "unparalleled" right. With a BS in Physics and a Master's in Applied Science I'm not the best choice for checking anyone's spelling (real glad Microsoft put spell check in their software).
  8. diesel

    diesel New Member

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    How fast do you want go?
  9. brianwill

    brianwill New Member

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    Sorry, forgot to answer the most important question. I'd like to cruise at about 26-28 knots. Top end doesn't matter, I don't push the iron hard.
  10. diesel

    diesel New Member

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    I think you hit the horsepower rating on the head. The CAT C7 is what you need for power. Considering you're on a Texan lake, for service reasons, I would go CAT or Volvo. I wish I could tell you more on the C7. Now if this was my boat, I would use the MAN D0836, but I'm in the Pacific North West so parts aren't a problem. For you, stick with CAT or Volvo
  11. brianwill

    brianwill New Member

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    Thanks for the info. This project will probably be after we move the boat to the US East coast, so does that change your thoughts on the Cat / Volvo vs. the MAN? I appreciate your insights on this discussion.
  12. brianwill

    brianwill New Member

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    Diesel,

    I've been collecting data on all of the engines that I think would be players for this retrofit. I'm confused by the differences in the performance data graphs, e.g., BHP vs shaft HP, vs. HP, are there any academic references that explain these terms? How would you convert a BHP to HP for instance?

    With regards to the comparisons I'm doing, what do you think about displacement vs. HP? I've noticed that the 450 HP class displacements are 8.3L for Cummins to 6.9L for the MAN, with Cat and Volvo in between these two. Is it "better" to have more cubes per HP or doesn't it matter?
  13. diesel

    diesel New Member

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    You can count on a reduction of 15% between BHP and SHP. There is no replacement for displacement. Except in this case. The MAN uses a dedicated oil cooler for piston cooling which greatly enhances its durability. Weight is a majour consideration in a 15 ton boat that is why I would use this motor. The CAT is light also mind you. Like I said before, CAT is very good with warranty. You may have some "teething" problems with such a new motor but they will be taken care of. I would still use the D 0836, now that you'll be on the East Coast. The Volvo's are great motors also. They also have a fantastic warranty. I don't like four cylinders.