Originally Posted by chewy
Bit like any engine really, if its looked after it'll have a long life. Quite a few marine diesels are marinised car and truck engines.
Almost all marine diesels up to a certain size are marinised versions of truck engines, although some installations are truck engines that are adapted (marinised?) and start a new life in boats.
Most diesels used in leisure boats are very highly rated, powerwise, in comparison with the truck engines they are based on. For instance, the Volvo D12 can be rated up to 715 hp in comparison with the 440 in a 44 tonne truck.
The Cummins B-Series 5.9 can be had with something in the order of 425 hp as opposed to about 250 in an 18 tonne wagon.
The IVECO website lists all its marine diesels in a number of different specs, depending on the kind of use.