Model A Thermosyphon with NO Waterpump

[H. L. Chauvin]

To reply 19, with the generator not turning it will be OK.

[Randy in Illinois]

I'm sure a good thermosyphon like the model A and Ts took a great deal of engineering, but I feel the system is marginal at best without a pump. Thermosyphon system relies on heated/hot water riseing and spilling over in to the radiator, ( normal heat transfer goes from hot to cold) so the heated water would move down to the cooler part of the radiator and would provide some cirulation. The model A system would get you home in a pinch if the pump still turned with a fan or not. Interesting, model Ts had the waterpump on the inlet side of the system where as the model A has the pump on the outlet side of the system.
I wouldn't want to overheat too many times, the way our 80+ year old cars have problems with cracks and headgaskets.

[ursus]

This discussion reminds of a fan blade I would like to see on the market. Picture an original looking fan blade that is lightweight and capable of flexing to reduce drag at higher speeds. I like to run a shortened original fan and find that it still provides adequate cooling and is much less likely to break up.

[redmodelt]

Any Model T with a water pump ether has a bad radiator or driver does not know how to set spark and spray needle or is uninformed. The T did not come with a water pump and with a good radiator should not need one. There were at least two Model T water pumps that were installed in the same place as the A in the outlet.

[Mark in MT]

I did an experiment for 3 years on my coupe, I was running a water pump with 2 impellers that were less than 50% there, the other one was gone. I ran this pump without a fan, it never got hot, although I didn't run it in a parade. Mountain passes at 90+deg didn't affect it. Two things to note, one is a great original radiator, the other is a worn engine with very little friction. I would not recommend this for everyone, I just wanted to prove to my self that if your car is running hot, you need more coolant flow and more blades on your fan.

[James Rogers]

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Tom, I have a 94 Ranger with a Mazda 4 cylinder 2300 engine. When I got it, it had a badly burnt valve and I had to replace the head. It was as cheap to buy a head from a reman, than to try to fix mine since it was cracked anyway. Once fixed, I registered it and began to drive it daily. This was last winter and I soon found out the heater wouldn't put out any hot air. New radiator and heater core and still no heat. I finally pulled the heater hose and started the truck and no water came out. I put a water hose in the line and all was open and water ran fine. All this time the truck temp gauge never got but to the lower temp range and never overheated. I finally decided the water pump needed looked at and maybe the impeller was rusted flat or something. Took out the pump and the impeller just fell off. It was in great shape but had come detached from the shaft. I drove this truck probably 500 miles like this and the previous owner drove it like this way more than that. I am convinced this is why the previous owner replaced the radiator and heater core and why it burnt the valve on #4. I am also convinced that the reason it never overheated was because it was thermosiphoning. I don't know why a Model A wouldn't do this but have never heard of anyone trying it. I will say I have a 1916 and a 1921 Model T and neither have a pump. In fact I bought the 21 it had a pump and I removed it because I don't like the look and don't think it needed it. I was right.

[James Rogers]

Originally Posted by Randy in Illinois

Is that why many model Ts were converted to waterpumps? I noticed both add on ones from the time. some look like they could have been from the factory. How good was a model T without a pump? Didn't they have a fan on and idler pully or something?

I have run my 16 in 95 degree weather and let it idle for several minutes on a paved parking lot in that temp without it overheating. I also took it to Kanab,Utah this July and made several 180-200 mile runs to Brice Canyon and the Grand Canyon and it never overheated with 4 people in the car. A T should run anywhere without a water pump.

[James Rogers]

Originally Posted by sidhartha

I think to find the answer to Toms question you would have to remove the pump from the system entirely. Take the water pump off the car and put a plate over the front of the head. That would eliminate any restriction, along with any external force moving the coolant. Thus making it rely solely on a themosyphone system.

It would not work doing that. You still have to have a fan to pull air through the radiator or keep it moving at speed. Model T's have a fan, even without a pump.

[Jim Mason]

this is per a little booklet called 'ford fax' published in 1929:
A centrifugal pump, with a three-blade, 2 1/2" rotor, is located in the front of the cylinder head. This pump is driven by a fan pulley keyed to the pump shaft. the fan is the two-blade, airplane propeller type, 16 inches in diameter, driven by a V-belt, 5/8" wide. The shaft is carried on a flexible roller bearing. The fan has a capacity of 855 cubic feet of air per minute at 1000 RPM of engine. The radiator is the fin and tube type containing 2 1/2 imperial gallons. It has 94 tubes staggered for maximum efficiency. The cooling system is so designed that it will function by thermo-syphon at low speeds, the pump acting as a booster at high engine speeds. This permits a cold engine to warm up quickly, but prevents overheating at high engine speeds.


Should the pump get out of order, the water will circulate by Thermo-Syphon, independent of the pump action, as sufficient clearances have been allowed to permit water to pass by the pump impeller.

[sidhartha]

Originally Posted by James Rogers

It would not work doing that. You still have to have a fan to pull air through the radiator or keep it moving at speed. Model T's have a fan, even without a pump.

That's true. The fan is needed when it sitting still.

[1967 Ford]

Originally Posted by Hicktick

I don't want to hi-jack this but say you lost the water pump and could not run the belt , what to do about the generator ??

If you run without a belt , wont it ruin the genny ??

It will not hurt a generator if it is not spinning (ie:-broken belt) The only problem is you will not have a charging system and everything will be running off the battery until it goes dead and then the engine will stop.

Also..
I am sure most of you remember that many 60's cars and such had fan clutches.
So the fan was not turning at high speed to save power from being robbed from the engine. Many cars do not need fans at all when driving- only when the car is not moving or traveling very slow.

[Roland/Pittsburgh]

I'm planning to do some experiments this summer when the weather is hot here in western PA. I want to determine if I can reduce the water flow rate and still avoid overheating. I plan to do this by removing material from the water pump impeller vanes. Maybe as much as 2/3 or more of the vane.

My purpose is to avoid suction pressures in the block that are significantly lower than atmospheric. As we know,boiling may occur at less than 212Deg. if the system pressure is lower than atmospheric. I believe this is a possible cause of water pushing out the overflow if the radiator is too small (two row) or some of the tubes are clogged on a three row unit.

Roland

[Joe K]

Originally Posted by Hicktick

I don't want to hi-jack this but say you lost the water pump and could not run the belt , what to do about the generator ??

If you run without a belt , wont it ruin the genny ??

Prolly wouldn't know the difference. When the generator isn't turning, the cutout (or a diode) serve as the electrical check valve to prevent the generator from motoring.

Your lights just get dimmer and dimmer and then finally as the battery gets VERY depleted (no low voltage cutout like a modern car) you finally lose ignition.

Joe K

[BarracudaBoy]

Originally Posted by Hicktick

I don't want to hi-jack this but say you lost the water pump and could not run the belt , what to do about the generator ??

If you run without a belt , wont it ruin the genny ??

My generator quit in Nashville and I drove home to Clarksville without it missing a beat! I was impressed!