Help with low pressure engine

Discussion in 'DIY Marinizing' started by rexxer, Mar 1, 2009.

  1. rexxer
    Joined: Mar 2009
    Posts: 5
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    Location: London Ontario

    rexxer Junior Member

    Location: London Ontario
    I am looking for some solid advice for my specific situation. I would really appreciate it.
    I bought a boat and contrary to what I was made to believe the engine doesnt work. It is a 1980 omc 4 cylinder. Keep in mind this is my first boat. I brought it to a marina shop and was told it doesnt hold oil pressure. It starts and all that but wont idle and stalls. The mechanic said it could be a variety of things and omc is **** and he wouldnt recommend fixing it.

    I have spare time, and am surrounded by mechanically inclined people who are willing to help me whatever i choose. I also have full access to a shop with engine lifts, and all the bells and whistle for auto repair. Many of my family are familiar with rebuilding, replacing auto engines.

    So my situation is I am not rich and cannot afford to buy a new engine anytime soon of drop a fortune into this.

    I also have an engine that works great from an older 90s Nissan Pathfinder. I am wondering if you guys would reccomend trying to rebuild this baby, and if so what i am looking at spending and doing, or trying this controversal auto engine swap.

    Any opinions and guidance would be so greatly appreciated.

    The engine is in a 1980 searay 190

    Thanks again !!!
    Mike

    Also I live in northern ontario and would only be using the boat on small freshwater lakes

    I posted this in a very old forum and figured this may be a better way
     
  2. Guest62110524

    Guest62110524 Previous Member

    take some pics of the thing, lets work thru it
     
  3. rexxer
    Joined: Mar 2009
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    Location: London Ontario

    rexxer Junior Member

    Its out at the farm so next time im out there likely this week, ill take some pics, Is there anything in particular i should focus on
     
  4. rasorinc
    Joined: Nov 2007
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    Location: OREGON

    rasorinc Senior Member

    Your 4 cyclinder is most likely a 3.0 GM block and you can buy exchange (rebuilt blocks) throught the US quite cheaply and use your old manifolds, starter, water pump, etc. Here is just one link of many I have on file. just google rebuilt marine engines. http://www.michiganmotorz.com/conditions.php
     
  5. rexxer
    Joined: Mar 2009
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    Location: London Ontario

    rexxer Junior Member

    Thanks rasorinc Ill research that. Ive looked around Ontario which seems to be quite futile. I am assuming having something shipped in from the US would be killer on delivery charges considering the weight.
     
  6. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    You have only a few choices, rebuild or replace. Replacing is easier, rebuilding can be cheaper, but it takes longer and you could end up with a hunk of iron that's not worth the money you've tossed at it.

    There's nothing wrong with OMC, that isn't wrong with everyone else's engine. Besides it's not an OMC engine, it's probably a 181 CID GMC block with a OMC label on it.

    These are quite plentiful in the bone yards, even over there. Most blocks are salvageable with some machine work.

    A rebuild will set you back the price of rings, bearings, seals and gaskets, plus the labor to tear it apart, clean it up, install the new parts and reassemble. If you can rebuild an engine then it a good choice and saves a fair amount of replacement cost. Do yourself a favor and replace the timing set, and distributor drive gear, as well as the oil pump.

    The problem with transplanting an automotive engine, particularly one that isn't especially common, is you need a special marine grind cam, fuel delivery issues and the dreaded exhaust manifold woos that can drive you insane if the parts aren't commonly available. I don't know of any Pathfinder engines used in the marine industry, so you'll need a custom cam and manifolds, which will rival a replacement engine in cost, just by themselves.

    Rebuilding what you have, eliminates much of the need to scrounge around for odd ball parts. You already have them, just on a dead engine. Breath new life into her and you will not be haunted by ghosts as you chase down bugaboos introduced in a transplant.
     
  7. rexxer
    Joined: Mar 2009
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    Location: London Ontario

    rexxer Junior Member

    Thanks Par that is good sound advice. Im starting to think that the nissan salvage might not be worth the effort.

    What would one average the cost of a rebuild, given that there are no unexpected surprises. I am trying to fiscally compare a rebuild to buying a remanufactured engine with a warranty
     
  8. rasorinc
    Joined: Nov 2007
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    Location: OREGON

    rasorinc Senior Member

    You are fairly close to Michigan Motorz and could pick it up there or have it shipped to a closer US border city or town
    in northern or eastern Michigan
     
  9. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    A basic 181 CID crate engine, with valve cover, timing set, harmonic damper, water pump and oil pan is about $2,000.

    Rings, rod bearings, cam bearings and main bearings will cost about $100. A gasket set for that motor will be about $90.

    Honestly, while you're there you should replace the lifters ($35), push rods ($30), oil pump ($30) and all tune up parts, plus the distributor parts.

    This totals out around $300 to $500, depending on what you need. If the cylinders need to be cut, then you'll need pistons (about $40 each), if the cam is worn out it will set you back $120 or so.

    You never know what you'll find until it's disassembled and cleaned up. Not to mention if you've never done this sort of thing before, you're not going to enjoy yourself much. If you have a gearhead friend then buy a case of beer and invite him over.
     
  10. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    What you do is perform a compression test with it in situ ...then remove and strip to see what you need ..may only be an oil pump ...maybe a crank re grind maybe no pistons required ....maybe just take the sump pan off ..not even the head ,,,,,any way you got to take it out ...strip and look and deceide
     
  11. Frosty

    Frosty Previous Member

    Change oil and filter and get a mechanical guage. Lets get some facts before we cut its heart out. Is the relief valve external?
     
  12. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    By "doesn't hold oil pressure" do they mean that it drops when it warms up or that it never builds up?
     

  13. apex1

    apex1 Guest

    First it does mean: when it is still not running (after some two month) it can replace a anchor.
     
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