RoyJ wrote:

-Why not use a big truck radiator? It should be mounted vertically so
that you complete the syphon effect.
-The radiator (or larger tank) needs to be on the same level as your
engine.
-Don't pressurise it at all, just have an overflow tank


I would mount the radiator at 45 degrees from vertical and above your
engine. my reasons are that flow occurs because the hot water going to
the top of the radiator is somewhat lighter than the cooler water
going from the bottom of the radiator to the lowest part of the engine
water jacket. So the hot water rises. The longer the pipes to the
radiator the greater the difference ( but somewhat offset by greater
frictional losses ).

At 45 degrees so the air that is heated rises through the radiator
without needing a fan.


Dan