Mercruiser 165 vs GM250 automotive?

Discussion in 'Gas Engines' started by Danielsan, Aug 6, 2021.

  1. Danielsan
    Joined: Jul 2004
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    Location: Belgium (Europe)

    Danielsan Amateur designer-builder?

    Hi all, projects go slow way to slow...and in between **** hapens...
    I was in the process of rebuilding my my mid 70's - 165 Mercruiser this until last month my basement got flooded with water and mud ... so all engine, carb, electrical, hydraulic parts, drive etc are mosly lost...
    finding a 165 in Belgium or even EU seem not easy... it seems easyer to find a chevy that used the GM250 in it... so my question would be to know if there are some differences between the merc and the automotive engine? i know already pump and alternator are different.... what else?
    any help appreciated....
    or should i just convert my Fletcher to an outboard :)
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Was it a GM block ? Or a Ford ?
     
  3. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    Hi Daniel and welcome!
    That GM engine is used by Volvo Penta as well, and I think you could find one in pretty good shape, they are quite common in Europe. The difference lies mainly in the connection to the drive, but you should be able to switch over the Merc bellhousing/aft engine mount from the old iron. Good (or at least better..) luck!
     
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  4. Danielsan
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    Danielsan Amateur designer-builder?

    a first search doesn't give me much hits on Volvo / GM engines.... any type in mind?
     
  5. Danielsan
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    Danielsan Amateur designer-builder?

    It is GM as the piston ref numbers are the same as GM automotive numbers.... and the information seems to match mostly to GM
     
  6. baeckmo
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    baeckmo Hydrodynamics

    Look for Volvo Penta AQ 175, AQ 205 and similar; that's the GM V6.
     
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  7. Danielsan
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    Danielsan Amateur designer-builder?

    These are the V6 models I have straight in line …
     
  8. baeckmo
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    baeckmo Hydrodynamics

    Ouch.. that one, better try in a museum?
     
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  9. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    Why do you say all is lost? The damage is only some light rust, the mud can be pressure cleaned off. The rest is standard rebuilding stuff, it's only a problem if you can't find the next dimension parts. Did you already do the machining and everything is maxed out? Carbs, electrics, etc. are similar, wash and dry, sandpaper the corrosion. Hydraulics are only a problem if the ram is rusting, that needs replacement.

    The chevy inline six has the same bellhouse bolt pattern as the V8, so you can replace it with a small block V8 up to LS3 (if you have the space), or a diesel.
     
  10. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    I agree. If the engine does not have rust buildup in the cylinders it needs to be cleaned and re-assembled. A slight surface rust can be cleaned, and maybe install new rings.
     
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  11. Danielsan
    Joined: Jul 2004
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    Danielsan Amateur designer-builder?

    I will need to find a new replacement parts as all has been flooded and some parts are lost in the mud like push rods, valves, other engine components will need to be replaced, starter, oil pump, crank shaft regrinded etc.... looking for some way to see if it makes sense to continue this project...
     
  12. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    I would upgrade to a newer engine, it's just the better option. Cheapest option is probably a used V8.
     
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  13. gonzo
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    gonzo Senior Member

    Was the engine disassembled and all parts scattered in the bottom?
     
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  14. Danielsan
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    Danielsan Amateur designer-builder?

    Yeappp :(
     

  15. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    Move on.

    repower, forget the automotive engines
     
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