Re: [bolger] Re: MICRO TRAWLER
- Yes this is all true. Back in the 1960's we used to marinize v8 gasoline engines for Chesapeake Bay work boats. WE always looked for a truck engine because they had four bolt main bearings and I think maybe an extra main though I am not sure about that. Most Of the small diesel boat engine are industrial stationary engine that the manufacturer has marinized. There is not much difference between an engine running a boat and one running a water pump 24-7. I think that the Volkswagen 4 cylinder automobile diesel engine did not hold up well. I had a 3cylinder Izuzu diesel in a boat and it was a marinized industrial engine. I had trouble with the #1 cylinder and again after rebuilding. I figured it was designed to set flat when running and the incline may have been a problem?? My experience with outboard engines is that they don't last long in my experience. This may be due to running wide open all the time?? I can't speak for the 4 cycle high torque engines with propellers intended for slower none plaining boats. They may be great? Doug
On 11/16/2012 12:29 PM, JOHN WALLIS wrote:
Good points Susanne. Also consider that automobile engines typically only run @ about 20% of rated max HP around 80% of the time (coasting, idling at the stop light, flat terrain cruising etc).
On the other hand, when you consider hull drag, prop thrust and friction, marine engines are constantly going uphill towing a trailer and are designed accordingly. My recommendation is a 4 stroke outboard until you get into larger boats where a diesel inboard makes more sense.
- True Doug, Ford FE gas truck engines had larger diameter crankshafts and cam profiles designed more for low RPM torque, compared to the equivalent car engines. Some GMC truck gassers even had exhaust valve rotators and stellite valve seats, anticipating heavier engine load demands.Your Isuzu may have had oil starvation issues if the oilpan capacity was not increased and the pickup lowered. I have a marinized 1956 Packard V8 with the oilpan capacity increased from 5 quarts to 4 gallons and an integral oil cooler built in. Most working boats of 25-30 feet and up have gone diesel but that may not be a practical option for the MT being discussed. 4 cycle outboards have been around for several years now and have a good track record even in small commercial fishboats that get hard use.