Richard Casady wrote:

You left out Caterpillar, Cummins, John Deere. Or are you only
interested in puny engines for tiny boats?

Such lists are always personal preferences, especially when not specifying
the criteria by which the selections were made.

But anyway, not to talk about "puny engines for tiny boats", I came across
this page: http://people.bath.ac.uk/ccsshb/12cyl/ It is about the
Wartsila-Sulzer RTA96-C turbocharged diesel engine. Available in 6 to 14
cylinders. Some facts for the larger end of the scale:
Total engine weight: 2300 tons (The crankshaft alone weighs 300 tons.)
Length: 89 feet
Height: 44 feet
Maximum power: 108,920 hp at 102 rpm
Maximum torque: 5,608,312 lb/ft at 102rpm

Maybe a bit off topic for this newsgroup - I doubt anyone here will ever
build boats that can use even the smaller versions of this...

-H