Thermostats

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Using a Brassworks radiator, my engine would only get to 135 deg.
I added a 160 deg thermostat and it heats quickly and stays at 160 all the time.
The engine is stock.
Hope this helps. . . .
Dick
 
There are no cons so long as the thermostat is working and installed properly.

[FONT=&quot]Corn fuel dictates the engine must operate above 160 degrees to burn clean and efficiently.

Higher engine temps caused by a thermostat will allow engine oil to rid itself of condensation.

The thermostat allows the block to heat evenly - Well, as even as it gets with the stock Model A cooling system.
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The purpose of the thermostat is to keep an engine at its ideal operating temperature of approximately 160 to 195 degrees. Cylinder wear is reduced when an engine operates between those temperatures. The Model A cooling system was not designed for a thermostat. Adding a thermostat is a design change. It changes the cooling fluid flow when closed and when open as the orifice is smaller than the hose. A thermostat will allow and engine to get from zero to 160 faster than without one so yes less wear when cold. The question is what operating temperature will your engine be at with versus without a thermostat? If it does cause your engine to run above 195 more often than without then wouldn't you be causing more cylinder wear?
 
Using a thermostat in a Model A Cooling system is a definite design enhancement. The question is what temperature thermostat to use. Cooling system designers for new cars generally use the 195 degree thermostat in order to minimize pollution. A 160 degree thermostat is viewed by some people as being too cool, but is it too cool for a Model "A" engine? A 180 degree thermostat is probably about right unless anyone has engine wear data that says otherwise.
 
We can OVERTHINK the thermostat thing. I put 12,000 Miles on Minerva, with a sleeved, 160 thermostat in the upper end of the upper hose, EASY!! MODERN thermostats RARELY ever fail.
Bill Cool
 
BILL WILLIAMSON said:
We can OVERTHINK the thermostat thing. I put 12,000 Miles on Minerva, with a sleeved, 160 thermostat in the upper end of the upper hose, EASY!! MODERN thermostats RARELY ever fail.
Bill Cool
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You're quite right, Bill - they rarely fail but I had one act up only 2 weeks ago. It was a 160F T'stat that would go to 190 in a hurry, then back to 140-150 just as quickly and repeat. I concluded it was sticky. A new 160F T'stat and now it goes to 160, pauses as the T'stat begins to open, keeps rising to about 170, then drops back to about 140. It moves up and down a little for a few miles, then settles on just under 150. I figure a 160 T'stat begins to open at 160 but isn't completely closed again till about 140F as it cools. 150- F is where it settles as it closes and the system is in equilibrium. I'd like a little warmer but I'll settle for it. My next T'stat will be a 180 one.
 
How, where are checking temperatures to see the swings? I use thermometer in the radiator and don't see swings like you are seeing?
 
Big hammer said:
How, where are checking temperatures to see the swings? I use thermometer in the radiator and don't see swings like you are seeing?
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I quoted those figures from the in cab gauge with sensor in the water outlet on the head, just below the T'sat.
If the thermometer you are using is a motometer in the rad cap, they are notoriously inaccurate and slow to respond because the bulb is not in the coolant. That might iron out swings like I get so you don't see them.
 
The attached article concerning thermostats appeared a while back in the Victoria Association newsletter. I had been of the opinion that the addition of a thermostat to a Model A was good idea. However, after a costly engine failure I have changed my mind.

A thermostat may work ok with a stock radiator or a poor repo, or one that is clogged. In my case I have a highly efficient 4-row core radiator. The engine had a few thousand miles on it after an overhaul and was driven regularly. On a 90 mile trip I had been cruising along at 55-60 mph in overdrive for over an hour. The day was cold with the ambient temp below 60 degrees. I had been watching my temp gauge and noticed that it never came up to 160, witch meant the thermostat never opened. The temp probe is inserted in the upper water outlet casting. The engine all of a sudden seized. The two photos show the damage. Number four piston melted.

This same exact thing happened to three fellow club members under the same circumstances.

The fault may well have been the poor quality pistons which all four of us have since replaced with quality Silv-O-Lite pistons. However it does not change the fact that the thermostat remained closed. The temperature of the water may have been below 160 at the thermostat, but the number four piston may not have been receiving a cooling flow of water and it could have been much hotter in that area.

I am of the opinion that the Model A engine was not designed to operate with a thermostat. There is no bypass in the water jacket to allow water to fully circulate when the thermostat is closed, like on a cold day.

Tom Endy
 

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I'm curious Tom. If your engine never got up to 160°F with the thermostat closed, what does it run at with the thermostat removed? You would think that with NO circulation at all, the whole engine would be pretty toasty?

As I'm sure you know, it is not a good thing to run an engine too cold either with unburned hydrocarbons and water from the combustion process collecting in the crankcase, contaminating the lubricating oil. A warmer running engine will vaporize these and (hopefully) be remove out the breather or road draft tube.

Maybe you should rethink your "highly efficient" radiator? :p:p
 
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I feel that by-passes are NOT needed. Minerva ran fine for 12,000 miles, with a 160 in the upper end of the upper hose.
Bill Simple
 
Bill is right ref modern thermostats, however I think this only applies to good quality stats such as those produced by Stant or the other quality manufacturers. I wonder who actually makes the stats that the Model A parts suppliers sell?
 
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