>>Also a problem is the plumbing to convert the coolent water into the copper
>>tube.
>Not to mention finding the coolant water in my air cooled.  Did anyone 

You can get a 'water heat-exchanger' that replaces the standard air-cooled 
engine's heater box. This heats water so you can use a heater/demister unit 
from a water-cooled car or, if in a camper, as a source of hot water for 
washing or showering. If you just hook this up to a tank above the hieght of 
the engine, the water circulates by thermo-syphon so you don't even need a pump.

Andy E.