Model T Thermostat ???

[Unprr]

I’m putting in a new Brassworks radiator into my T. My question is this. Is it useful to also put in a thermostat, like the one in the photo.

George

[Moxie26]

Your new Brassworks radiator will cool the engine without a thermostat. Thermostats were used along with add on water pumps.....since coolant was pushed thru the radiator with some speed, the thermostat slowed down movement , and also reduced coolant being pushed thru the overflow pipe.

[Scott_Conger]

If you need something to ruin your tour some day in the future, this would be the ticket.

Assuming you do not have a water pump (and you shouldn't, with a new radiator), coolant will not flow with gusto in a thermo-syphon system until a significant amount of heat has built up anyway. Since the cooling system is self-regulating in that respect, there is no need to add a trinket that has the opportunity to randomly fail on you.

PS - you're going to love that new radiator

[Unprr]

Thanks for the fast replies from both of you. That was the way I was leaning but needed a push.LOL.

Scott, I like your line. Tyranny under the guise of law is still Tyranny

[John.Zibell]

I run a 160 degree thermostat with no water pump with a Berg radiator. What I find is even temperature front to back of the engine. All my spark plugs stay clean. My friend doesn't run a thermostat and the rear of the engine is significantly hotter than the front, and he gets significant buildup on his front two spark plugs. A thoroughly warmed engine will run more efficiently. On cool days, I have a consistent read in the moto meter, my friends cars may not show anything in the meter. I ran farm tractors (Model G Allis Chalmers) that are thermo siphon and run with a thermostat. BTW, the same thermostat has been in the engine since it was built in the early 1950s.

[TWrenn]

NO!

[TXGOAT2]

A thermostat is not needed on a stock Model T system.

The engine will run most efficiently at 190 to 200 F.

I don't think a thermostat would contribute to uniform engine temperature unless a water pump was also installed. Absent a water pump, a thermostat might contribute to temperature imbalance by restricting circulation.

In a case where significant front to rear engine temperature imbalance is consistently observed, I would look for such causes such as fuel mixture imbalance due to a leaking intake manifold gasket, or some other cause, such as debris in the cooling system, clogged steam vents, head gasket leaking or improperly installed, etc.

While spark plug deposit characteristics can vary due to poor cooling system performance, other causes, such as fuel mixture imbalance or oil control issues or ignition system problems are more likely to be the culprit.

One virtue of a good water pump installation would be a more even engine temperature, but the standard Ford thermosyphon design obviates any need for either a water pump or a thermostat except in cases where an engine is modified for high performance or operating in very heavy duty service, such as in a loaded TT truck operating under severe conditions of high ambient heat or high elevation.

IF a water pump is added, a thermostat is needed to prevent overcooling under some conditions of operation. In that case, I would use a 180 F thermostat with a small bypass hole (1/8") drilled in it to allow some coolant bypass when the thermostat is closed, and to allow air to escape from the system when filling with coolant.

A thermosyphon system will not circulate coolant to the radiator until the engine coolant is well warmed up. A thermosyphon system will increase circulation in any portion of the block and head that is running hotter than normal, assuming nothing is obstructed.

Circulation in a thermosyphon system, being heat-driven, will speed up when the engine is loaded, and decrease when it is idling or running lightly-loaded or in cool weather. The result is a self-regulating system.