I have recently acquired the Families 1926 Model T. I have started to go through the cooling system replacing parts as needed. There was no thermostat in the engine block that I found. What are the advantages or disadvantages of putting in a thermostat? I've read most of the water pump forums an have not found a solid answer. I have no plan to put a water pump on at this time. I currently live in Phoenix don't know if this makes a difference in how you'll choose to answer.
Isn't the purpose of a thermostat to speed up the heating of the coolant and keep it heated? I doubt that's needed in Phoenix.
Thermostats were installed as part of the installation of a water pump. If you don't intend to put on a water pump, forget the thermostat.
The "Thermo-Barf" cooling system engineered into a Model T works remarkably well all by itself. As you might imagine, it depends on the parts working as intended. What I mean is, the internal water passages in the block and head need to be relatively clean and open, and most important, the radiator needs to work.
Over time, two things happen to a radiator. One, since we all stubbornly refuse to use distilled water, calcium and other minerals from the water coat the insides of the water passages, and insulate the tubes from the water.
Two, and more to the point, the connection between the tubes and the fins loosens. This is critical. If the heat can't get from the water to the fins, to be shed into the air stream, then nothing else can work as intended, water pump or no water pump.
So, forget the thermostat, run some cooling system cleaner through the system, and then see how your T works. Remember, retarding the spark (pushing up the left-hand lever) causes the engine to heat. You'll find the "sweet spot" for that lever as you learn the car's personality.
And all Model T's have unique personalities!!
The following is a list of the top 5 reasons to use a thermostat on a Model T:
The 160 is used without the water pump, a 180 with. If your radiator is in really good shape (like some of the new ones) it can run too cold. Adding the 160 would be like adding a piece of cardboard to raise the engine operating temp. to where it is at the correct temp which for most engines would be in the 170-180 range. In Phoenix you probably don't need one, try with out it.
If you lived in very cold climate the thermostat might help you. I think you would need some type of bypass to get some of the water to go past the thermostat because with thermosyphon, your circulation is dependant on temperature differences and the hot coolant rising. So if you put the thermostat in the intake you would overheat, and I am not sure the coolant would rise to a thermostat placed at the top either without bypass. The hottest part of the engine is around the firing compartment right atop the pistons.
In Phoenix, you would need the best cooling system available and a thermostat is used to keep the engine warm, not cold.
Before thermostats they used to block all or part of the radiator so the engine would warm up faster. So theoretically, a thermostat is not needed. Similarly to spark lever vs automatic spark advance, or manual shift vs automatic.
I have found that going uphill on a 100+ degree my cars will not overheat, but at idle they tend to get hotter and when I turn of the engine it will gurgle for a few seconds. That is normal for thermosyphon and only does it on very hot days.
Once the engine get up to temp the thermostat will open and as long as the water in the system is hotter then the rating of same it will stay open allowing for burping till cool. It's not like when you turn off the motor it just shuts tight. Besides, most have a bleed hole that allows for some water/air movement even before the diaphram opens or shuts.
Steve Forest had a water pump on his 1915 car. He took it off for reasons I won't go into now. He had lots of overheating problems, boiling over and all. He finally discovered the thermostat in the water outlet at the top and took it out. Overheating problems solved. Don't run a thermostat with a thermosyphon system but do use one with a water pump.
The thermosyphon system depends on a difference in water temperature to work. This works as a natural automatic thermostat, although not as precise as the modern thermostat. The water will not circulate until the engine gets warm.
BTW, a warm engine is a happy engine.
Chance are it was a 180 thermostat.
I've run a 180 thermostat in my daily-driver T for years and years. It has no water pump and no fan. but has a good radiator. It works very well in all weather conditions. I have a temperature gauge (below the thermostat) and a Moto-meter, so I can see the interaction between the motor and the radiator.
What the thermostat does is force the temp of the engine to rise to above 180, at which point the thermostat opens and lets a little relatively cold water from the radiator flow into the motor. Then the thermostat closes again. While the thermostat is closed, the radiator is free to cool the little bit of hot water the flowed into it. This process continually repeats itself until the entire system is at a higher temperature than the thermostat - at which point the system behaves as a normal thermo-syphon system. Under most conditions, however, there is a reserve of colder water in the radiator.
Having said all this, you really don't need a thermostat.
Steve Jelf is right; in the Valley of the Sun you probably don't need or want one. Where I live in the frozen tundra of northern WI a 160 degree thermostat is about the only way I can get my T to operating temp on most days. I tried running without it and the red barely shows on the motor meter at all and the spark plugs carbon up quickly. With the thermostat it reaches operating temp quicker and still cools correctly. Plus the spark plugs seem to stay cleaner (except for the front one which always runs a little darker). Even on the hottest days we have around here (low 90's) the red never get beyond the lower part of the motometer's circle.
Donít forget the other function of the thermostat.
Regardless of thermostat rated opening temperature it also acts as a flow restrictor. Using a water pump without a flow restrictor increases the likelihood of too fast a flow of water through the radiator and / or pressurises the radiator top tank and blow water out the overflow tube.
My own opinion is go back to the standard set up with a clean block and efficient radiator and repurpose the water pump as a wheel chock.
In theory, a thermostat would probably be ok. Where I live, it is certainly not needed. My main objection to one is that every one I've ever seen would offer a fair amount of restriction to flow even when fully open. If there were one that offered no restriction when opened, I'd be a little more accepting of them. But as said above, thermosyphon systems are self regulating. The greater the temperature difference between the top and bottom of the radiator, the faster the water will flow. However, i could see the scenario of the system never getting up to normal operating temperature on a really cold day. Blocking off the air to the radiator sounds like a better fix to me. That way, when it gets hot outside, there's nothing in the system to keep the coolant from flowing when you really need it to.
Keep it simple. Might work but totally unnecessary.
Well thanks for the information dump. I truly appreciate all of you sharing your knowledge and experience with me. I've waited years for my Dad to hand the T off to me he has taken good care of it for the past 23 years it's been garage kept an driven rarely. I had it hauled to Phoenix and started the inspection process to get it back on the road. So I'll be checking in occasionally for more information on different items. After the engine is running it will be wheels and bearings.
I run a 160 thermostat in my 1926, my friend does not run them. Using an infrared thermometer, he has a substantial difference in temperature with the front of the engine being much cooler. Mine with the thermostat is consistent front to rear. Also and engine runs best at the temperature Mark called out above. Running in the fall, winter, and spring my moto meter hardly registers if at all and I'm in the process of making a radiator cover to warm up the engine to a correct operating temperature. Thermo siphon will cool and engine, but it circulates with any temperature change and does not regulate temperature. Running an engine too cold is not conducive to engine life and the oil needs to heat up as well to vapor off any contaminants.