Lets build a Modern Engine From Scratch.

Discussion in 'DIY Marinizing' started by LMannyR, Mar 1, 2008.

  1. LMannyR
    Joined: Jul 2007
    Posts: 19
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    Location: West Palm Beach, FL

    LMannyR Junior Member

    Hello everyone.

    I've pulled my Mercury 350 out and trashed it after the machine shop said it had beyond repair corrosion. I did not mind since I wanted a NEW Modern engine.

    It will be put on a 23' Aft Cabin Welcraft. I'll use the boat mostly for intercostal cruising, pull a tube, and occasionally go out to the ocean for some light fishing.

    I'd like to have 300-350 HP, MPI, Closed Cooling, and a drive to match it.

    Should I start with a GM Performance Long Block and go from there? Then marinize it? or get a short block and go from there?

    Thanks
     
  2. rasorinc
    Joined: Nov 2007
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    Location: OREGON

    rasorinc Senior Member

    propulsion--lets build a new engine

    Look at Crusaders--and what the experts say. Best marine engines (gas)
    made. long life, compact, and seem to run forever with normal maintenance.
    Stan
     
  3. JCD
    Joined: Jul 2006
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    Location: Coney

    JCD Follow the Bubbles!

    Agreed.
    I have twin 1984 165HP, 3.8 liter inboards on my Bayliner 3270 and they Purr like kittens. Highly reliable and will not dissappoint you when you're offshore outside of tow service range. Go Crusader. Maintenance is key. Forget the 200 hour rule...go to 100 hours and a rebuild will be a long time away.

    J:cool:
     
  4. mongo75
    Joined: Aug 2007
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    Location: Orange County California

    mongo75 Senior Member

    Crusaders are high quality marinized TRUCK ENGINES, at a wealthy cost too. If you're looking to save a few hundred (or thousand) dollars, go with a new longblock from GM or Pep boys or wherever, and then bolt on the accesories from your old block. You did save everything, right??
     
    1 person likes this.
  5. Frosty

    Frosty Previous Member

    You say you want a modern engine then choose a gass guggling 1000hour life American V8.

    Modern ???? push rod valves ??

    What about a high speed Japanese diesel,--probably weight less.

    The rest of the world is trying to save fuel.
     
  6. charmc
    Joined: Jan 2007
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    Location: FL, USA

    charmc Senior Member

    Crusaders are marinized GM engines. Not cutting edge sexy technology, but about as reliable as gas engines for boats get. Good PM and freshwater based coolant will give them a long life. You can marinize yourself as Danny said and save some money, if you're up for the work.

    Frosty's right about diesels, though, there are modern designs combining lighter weight and better fuel efficiency with traditional diesel reliability. Offsetting those factors are the higher cost of the engine and the higher unit cost of the fuel. Don't know about the rest of the world, but in the US diesel prices have been 10-15% higher than gasoline in recent years. They definitely use less of the stuff, though.

    Write down the factors that matter most to you, then do some serious research and write down the benefits and disadvantages of each choice as it applies to whatever's most important to you. A pattern will develop that will guide you in your decision making.
     
  7. LMannyR
    Joined: Jul 2007
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    Location: West Palm Beach, FL

    LMannyR Junior Member

    Mongo, I did save everything. If the old stuff is bolted onto a new long block, then it's still the old technology with new parts. The old stuff was carbed. I want Multi port fuel injection with a programable ecu. Most likely, I'll end up ebaying all the old parts including the Exhaust manifolds and risers if I can't reuse em.

    I recently got an email quote from BamMarine.com

    ...................
    Engine only is $7895, $12,995 with a b1, $13,195 with a B3

    -----Original Message-----
    From: ....
    Sent: Saturday, March 01, 2008 10:59 PM
    To: engines@bammarine.com
    Subject: Help_with_engines

    How much for a Mercury 350 MAG MPI with and without a Bravo 1 and a
    Bravo 3.

    I'll do the installation.

    Thanks!!!
    ..................


    Thats a whole lot of money just to put "Mercury" on the intake cover. So I have done some research. I found GM's latest marine engines for 2009 here

    From the pictures on GM Marine engine broshure, they do not look any different from the auto engines from the exterior. I'd like to go with the LS2, LY6, LS3 setups.

    Anyone know if they are available as crate engines? If so, who can I get them from? Or do I have to piece it together save the label markup? Summit online does not offer them.

    To complete the engine package I'll need the GM ECU with wire harness. Where can I get those from?
     
  8. mongo75
    Joined: Aug 2007
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    Location: Orange County California

    mongo75 Senior Member

    Manny-
    I'm glad you're looking around, so you can realize the value of sticker shock LOL. Put "marine" or "aviation" on anything and the price gets jacked up.... The only problem with converting to EFI is that I'm pretty sure you need to install O2 sensors, so if that's the way you want to go, you can get risers with O2 provisions in them (if they do need them that is, I'm not 100% sure) HOWEVER, before you make the plunge, and if money is a concern, I would definitely run the numbers- see how much more it's gonna cost to convert to EFI vs. keeping the carb set up. Honestly, with a good electronic ignition, and a properly tuned carb, you can almost get the same efficiency as an EFI block.

    As far as getting a japanese diesel, (1) American diesels are better (2) you're looking to mount this directly to a Merc drive, w/a diesel you'll need a jackshaft and (3) unless you're a commercial fisherman, the initial cost of a diesel is not worth the long run savings.
     
  9. LMannyR
    Joined: Jul 2007
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    Location: West Palm Beach, FL

    LMannyR Junior Member

    We all know an EFI engine will have a higher initial cost. I'm willing to shell out the extra bucks for EFI.

    Diesel is way up there in price. Unless there is a Light weight version out in a car somewhere I can convert, GAS will have to be the choice. Heck, the diesel guys can pour straight vegtible oil as fuel, the technology is out there for the gas users to use water. Lets not go here though, this is a whole new can of worms.

    According to the GM Marine brochure, there are 2 inputs for O2 sensors. It does not specify if both are needed at the same time. If mercury uses risers with O2 Sensors, then it's a direct bolt on to the crate engine.

    Anyone know if Mercury uses O2 sensors?
     
  10. mongo75
    Joined: Aug 2007
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    Location: Orange County California

    mongo75 Senior Member

    I don't know if Merc uses them, but I'm pretty sure they would HAVE to, to ensure the proper fuel to air ratio. I'm also pretty sure any engine would use 1 O2 sensore per exhaust bank.

    BTW- I have run vegetable in my diesel before, I love free fuel!
     
  11. larper
    Joined: Mar 2006
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    Location: Sweden

    larper Junior Member

    If you want to convert a carb engine to EFI, take a look at http://www.bgsoflex.com/megasquirt.html.

    Ive converted my MB190 from carb to EFI with megasquirt and i know people around the word have converted all sort of things like cars, motorcykles, 4stroke, 2 stroke and boats.

    -- Per Larsson / Sweden
     
  12. Frosty

    Frosty Previous Member

    Why don't you ask how much a marine diesel is. Dont forget this will come with marine cooling system and gearbox, looms, guages exhaust, alarms every thing you need.

    The boat will be worth more by the marine engine. It will also have a warranty.
     
  13. TollyWally
    Joined: Mar 2005
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    Location: Fox Island

    TollyWally Senior Member

    Mongo,

    "so if that's the way you want to go, you can get risers with O2 provisions in them"

    Do you have any information on such a critter? I would like to use o2 sensors to monitor fuel ratios in my carbed big block chevy.

    Thanks
     

  14. mongo75
    Joined: Aug 2007
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    Location: Orange County California

    mongo75 Senior Member

    Wally,
    Although I don't know who makes them, I am pretty sure they're needed for an EFI / MPFI engine. I would do a google search for them.
     
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