Why have a thermostat unless you need quick warm-up times? It does not make the engine run cooler. The extra minute or two in warm up time does not seem worth the effort on a car that is not primary transportation. Am I missing something?
Why? When driving in very cool or cold weather, if you have a decent radiator, the engine never gets up to a good operating temperature, to warm up the oil, drive moisture out of the crankcase, etc.
Back in the Model A era, with no thermostat, they used a piece of fiberboard that blocked the lower 1/2 or 1/3rd of the radiator, to get the engine to run warmer. Often called a WinterGuard, you can find old ones on fleaBay. Oil companies, garages, etc., put advertising on them.
I take a piece of black plastic corrugated sign board and slip it between the radiator and the radiator shell in front, covering about 1/3rd of the fins at the bottom. It hangs from the headlight bar with 2 small strips of velcro. That does just fine for me in the winter. I don't seem to have a picture of it installed on the car here on my computer; I'll go take one later and post it.
When working on the car in the summer, to speed warm up in my driveway, I will slip that plastic winter guard in for 5 or 10 minutes to reduce warm up time, then pull it out.
It's not automatic like a thermostat, but it works. If the engine gets too hot, you can stop and remove it in a minute or less (never happened to me in the winter).
Henry did not put any form of bypass in the cooling system to be using a thermostat, to allow water to circulate through the block when the thermostat was closed, so that the block warms up uniformly (as is done on every engine that I have ever seen that was designed to use a thermostat).
I do not believe that it is good for the engine to have the coolant trapped in the engine by a closed thermostat until it is warm enough to open the thermostat. Then the thermostat opens and a slug of cold coolant rushes into the engine, suddenly cooling it down (especially in winter).
Then the thermostat closes because of the colder coolant hits it. Then it opens again as warmer coolant goes through it. Temperatures swing up and down until the thermostat stabilizes in the middle spot. I do not believe this is good for the engine. That is why engine designers put in the coolant bypass when they added a thermostat. (Some cars used the heater core as the bypass. It had coolant flowing through it all the time, even when heat was not called for.)
Henry's original design with no thermostat results in slow, uniform warming of the coolant and the block. With a Winter Guard it warms a bit faster. I think the old guy knew what he was doing.
Instead of fabricating a thermostat, fabricate a Winter Guard.
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