[SEL] Thermo-syphon Question

[Curt]

I think JB's coining of the term percolating cooling is an excellent 
description. These Moguls have the screen cooler mounted high above the 
engine so that the contents of the water in the pan can all drain and 
fill the block and head of the engine. There is no circulation of the 
waterjacket water as the engine heats up, until it reaches 212° F. Only 
when the water starts to boil do you see water making it up the return 
line and to the distribution tube across the top of the screen cooler. 
You see a healthy mix of steam out of the tube as well. This is probably 
an ideal operating condition for our engines at shows. Since we hardly 
work the engines allowing them to get really hot, this style cooling 
system assures you get to at least 212° F. This is a vastly different 
cooling system than the traditional thermosiphon system. With TS as soon 
as there is a few degrees of differential temperature, circulation 
begins and the block and head temperature is never warmer than the water 
in the tank. With a loafing engine this leads to all kinds of water and 
combustions products condensing on the cylinder and head walls of the 
engine. A lot of times when slow running a hit and miss engines I'll 
eliminate the water just to assure the engine gets warm enough to run 
decent.
The walking beam Alamo I finished last summer has a fixed volume water 
pump. I set up a bypass loop that allows the pump to continue working 
and pumping water thru the trickle down tray cooler, yet thru a valve I 
can independently control the flow thru the engine. When cold the water 
is completely off to the engine and once hot enough that I can't keep a 
hand on the cylinder head, I'll crack the valve open a 1/4 turn and 
allow a small amount of water to flow thru the head and cylinder. This 
has really worked out well and I think I'll add the same feature to the 
8HP screen cooled Famous. It has WAY too much cooling for the work I can 
put on the saw blade. Running hotter would be very beneficial.
Curt Holland
Gastonia. NC

Andrew wrote:

>I've never paid that much attention to those, I thought they had a water
>pump but still i'm having a hard time seeing how that worked with the
>water line below the port. I'm thinking I might do a little experiment
>with this, but I seen a tractor with I thermo-siphon setup over heat from
>the water line falling below the top port on the radiator. The water that
>was in the engine stayed level with the radiator, but the water in the
>engine boiled off instead of flowing up and out the top port on the
>radiator.
>
>>From Andrew at
>tech at andrew2.netpluscom.com
>engineering at andrew2.netpluscom.com
>b10730 at hotmail.com
>
>Visit the website at http://www.netpluscom.com/~10730/
>http://www.oldengine.org/members/andrew/
>
>On Fri, 19 Jan 2007, Edd Payne wrote:
>
>  
>
>>Got to contest this Reg.The IHC  screen cooled Moguls thermo siphon and the
>>water is well below the outlet.The water expands with heat and flows over
>>the screen.There is no pump.It works great.Anyone with one of these engines
>>will tell you this.Also the water tank on my tank cooled Stover W has the
>>top water outlet above the top water level.It does the same thing as the
>>Mogul and you can see the water flowing out of the top pipe as it heats up.
>>EDD PAYNE
>>PO Box 364 Gulgong N.S.W
>>Australia
>>    
>>