Conversion from Marine V-8 to 4 cyl diesel.

Discussion in 'Propulsion' started by CAPT. Ted, Oct 11, 2020.

  1. CAPT. Ted
    Joined: Oct 2020
    Posts: 1
    Likes: 0, Points: 1
    Location: Hollywood, MD

    CAPT. Ted New Member

    I have a nice 1988 20’ Shamrock Walk-through with the original Ford Pleasurecraft Marine 302 V-8, with a Velvet Drive AS-71C transmission. The boat has hard chines and a keel, but it is NOT a deep Vee hull. I am considering (Actually, I may have no choice) a repower; and am looking at a Volvo D2-60 or a D2-75. This engine swap would save me over 450 lbs, and I would gladly give up the 30+ mph top speed for a much quieter ride, and a top end in the upper mid teens. Back in the late 1940s and early to mid 1950s, 60-80 hp in-line 4 cylinder and 6 cylinder engines were commonplace for 16’ -20’ boats of about my same displacement (2,500 lbs after re-power). At one time, there were some on-line calculators about engine hp, torque, displacement, and prop size. By way of comparison, a NEW Matthews ‘22 Bay Cruiser with a Yanmar 100 hp 4 cyl with a hull configuration similar to mine, makes 22 knots. I don’t see a down side to doing this, but I’m curious if anyone else has done a similar swap.
  2. bajansailor
    Joined: Oct 2007
    Posts: 3,282
    Likes: 1,314, Points: 113, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

    Welcome to the Forum Capt Ted.

    I know a chap here who has a 1996 centre console Shamrock 20 - when he first got her about 10 years ago she had a GM V-8 275 hp petrol engine, and 2 years later he refitted her with a turbocharged 4 cylinder diesel Yanmar 4JH producing 110 hp, and he has been very happy with her ever since.
    He had to buy a new propeller, but I think that was about it - I think they still have the same shaft and stern tube.
    Edit - and I think he had to do some modifications to the beds, but not a lot.
    Last edited: Oct 11, 2020
  3. brendan gardam
    Joined: Feb 2020
    Posts: 367
    Likes: 45, Points: 28
    Location: east gippsland australia

    brendan gardam Senior Member

    I would like to marinise a hyundai r model 2.0 diesel from 2011 onwards hyundai and kia suvs. Lovely little diesel that put out around 180 hp.
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