[Cayoterun]

[QUOTE=Rockdriller;51777]'Yote,
When the V-12 was coupled to an irrigation pump, did they use a closed coolant system with a radiator....or was it cooled via open system (using pump water)....like a Marine Set...?[/QUOTE

Rock:
I'd call it a closed system, but no conventional radiator.
On the pump discharge pipe, (the end well water came OUT of), they have a pipe about 6 feet long and 3-4" bigger in diameter than the pump discharge pipe. The inlet and outlet pipe on the "cooling coil" is the same diameter as the pump pipe so well water passes thru this large chamber @ about 50 degrees. Inside the bigger chamber, it has 5 or 6 copper pipes about 2" in diameter running horizontally inside the big chamber and connected to an inlet and outlet welded outside of that chamber wall for the engine coolant hoses to connect to. The coolant is isolated inside the copper pipes from the well water, and anti-freeze can be used. Fresh well water, and coolant never mixes. So, the engine coolant is cooled by well water, as it passes over/around the continuous copper "cooling pipes".
The thing is shaped like a great big muffler to look at it from the outside, and this system is used on all well motors, regardless of size.

They do have a "surge tank" on the front of the motor so the coolant can expand and contract, as well as access for adding water, etc., that holds 5-6 gallons of coolant, but no or very little help in cooling. but it's all inter-connected.
The whole system holds 15 gallons or more.

This is a lot of words, and probably clear as mud, but hope you get the idea.