MTFCA Forum

This question oftten comes up in my other hobby, WWII military vehicles. Early jeeps had one piece rubber radiator hoses and then switched over to a steel tube in the middle of both the upper and lower hose lines. It is usually explained as a way to save a few inches of rubber during the war, although it involved twice as many clamps and hose connections for possible leaks.
Now, I'm working on a T and here is this same tube in the lower outlet line. Was not aware that saving rubber was an issue during T production, and HF even was creating Fordlandia to produce his own rubber.
So, the question is . . . is the brass or steel tube in the outlet connection there because of saving rubber? Allowing more flex to the connection? Or is it a way to improve actual cooling by allowing some heat to wick away through the metal tube prior to the radiator?

The jeeps used the steel tube in both inlet and outlet, so would not think it was beneficial to the cooling system. But, interested to know what the T hobby thinks of the reason behind the design.

I'll hang up and listen...

My guess would be that the metal dissipates heat better then does rubber - the metal pipe would contribute something to the cooling of the engine.

I have read the reason was so the hose didn't collapse when running hot and got soft, shutting off the water supply. Also, look at the price of tires and rubber cased batteries, not cheap items, cost of steel was still cheaper.

Metal pipe is durable, and it adds a few square inches of heat-dissipating surface to the cooling system. The surface area of a pipe is a little over 3 times its diameter X its exposed length.

A metal section in the upper radiator hose will be more effective at dissipating heat than one in the lower hose, but the Model T upper hose is too short to allow using a metal section of any significant length, and too much stiffness at this point can damage the radiator. The lower hose is not too short, and putting a metal section in it with as much of the metal exposed as is practical will help cool the engine.

I added a metal section to an upper radiator hose on a Packard 8, and doing so allowed 7" of exposed metal pipe at the hottest part of the cooling system. If my math is correct, that added about 28 square inches of extra heat dissipating surface. (1 1/2 X 3.14 X 7)

Straight rubber hose is very expensive today.

A T system with no pump is unlikely to collapse a hose, but old hoses can shed rubber and cause clogs.

A pump system can collapse lower hoses, especially if the radiator is restricted, or the pressure cap is defective, or the thermostat is removed.

All good points, but, again, my initial frame of reference is the WWII jeep where the first 50,000 or so, both assembled by Willys and Ford and the initial prototypes that were approved by the military had entire rubber upper and lower radiator hoses. So no worries about vibration, collapsing, rotting, etc. But then, the Japs had control over the rubber industry and the US military went into rubber saving mode. Using felt for gaskets and gromets. It is my understanding that gasoline rationing in the US had nothing to do with gasoline savings, but rubber tire savings.

And, early brass tubes is difficult to understand that brass would have been cheaper than rubber at any point in time.

So, just wondering what the thought process was during the initial design.

Another question to ask Henry.

Signsup...... You got a few accurate answers on why a metal tube was used on the coolant intake from the radiator to the Model T engine. Those early Jeeps supplied for world war II did have four cylinder engines similar to the model T and Model A, were they equipped with water pumps or use the thermosiphon system?.... If they had a tendency to overheat, the cheapest way for Ford to help solve was to use that metal pipe to dissipate heat at no real cost to them, and keep those Jeeps running. Sounds like you gotta research those early Jeeps to see how they were built and what problems they may have had.

My 2 cents worth and I’ll agree with Mark…. Several years ago an old friend asked me to help him find out why his Model T overheated in parades. It started easy and ran good but when I took it out on a 5 mile run, the radiator gurgled and gushed so I had to pull off the road. Upon inspection I found the radiator to engine inlet pipe was one long complete rubber hose and it had collapsed. Don’t ask me why. I can’t even spell fisics. He replaced it with an ugly rubber hose with a spiral spring inside. Car ran cool ever since.

The jeeeps did have thermostats and water pumps, and, yes, as our first military action in WWII was in N. Africa, perhaps overheating was an issue. But again, the jeeps had the metal in both the inlet and outlet hoses which I would think was not a heat dissapation issue.

Just installed al new hoses, tube and clamps on the WWI ambulance project and that's six clamps to tighten and watch for leaks. But, I like the look of the brass tube and the red hoses.

A lower hose that was too long to begin with might buckle and collapse, especially if soluble oil or brake fluid was added to the coolant. Generally, hydrostatic pressure would tend to keep a softened lower hose open, and the thermosyphon flow rate would be exceedingly unlikely to collapse the hose, unlike what can happen with a system that includes a pump. With a thermosyphon system,
negative pressure cannot develop. Negative pressure can occur with a pumped system, but it is never desirable.

My '17 touring had a one piece rubber hose when I got it. The hose hung down and rubbed on the throttle or timer linkage. I installed the pipe with the 2 hoses which stays above the linkage.

A fun discussion!!! As an engineer who designed thermosypons in my early years, I would tell you that thermosyphon systems are very sensitive to pressure losses. A straight steel pipe produces significantly less pressure loss than a rubber hose. All of the other comments are correct, the steel pipe does help in removing heat, and its likely cheaper and will last longer, but the controlling factor in my mind would be using the pipe to reduce pressure losses in the system.

Steve

We are talking about Henry Ford, it was either cheaper or faster or both. If it saved $.01 per car that's what $150,000.
Craig.

Interesting. I searched the WWII jeep forum that I am also active on and there is a thread from 2019 that describes the initial design of all rubber tubes and then a transition for both Willys and Ford to steel tubes in both upper and lower hoses. I posed the same question on that forum 4 yeards ago and it got ignored, but a previous comment suggest just to save rubber. Not to aid in cooling or to reduce hose collapse.

Wonder if other auto manufacturers in the T era used steel tubes as well. Was it a common automobile engineering thing?, or just a Henry Ford thing? The Willys production in WWII would suggest not a HF decision. Willys had the contract and Ford just assembled 280,000 jeeps under license to Willys.

Lower hoses are prone to collapse on pump systems ... especially if the thermostat is removed or the radiator clogged or both.

Thermosyphon systems lack the ability to produce a negative pressure anywhere in the system, and they do indeed require free flowing plumbing, radiators, and water jackets as well as other design considerations.

Rubber hoses can deteriorate in several ways that can act to impede flow, but steel can rust or become encrusted or develop pinhole leaks, which can allow air into a pumped system. Rubber hose interior linings have been known to partially detach and restrict flow, or even act like a check valve.This can happen even if the outside of the hose looks OK, and it can affect a pumped system or a thermosyphon system, though it's more likely to occrur in a pumped system at higher engine speeds.

Another possible reason. If the fan belt breaks, especially at high RPM it could cut the hose. I don't think the natural rubber hoses in those days were as strong as ours today.
Norm

It seems the Australian assembled improved cars don't use the solid tube. Mine, and other 26's in original condition I've seen, just have a long rubber tube without the solid piece. This idea of the tube collapsing under vacuum is invalid since the system is always at atmospheric pressure. The tube is certainly not soft enough to sag between connections. One advantage of the single tube is two less points of possible leakage.

When I put my first T together, not knowing what was correct, I went to the auto parts store and bought a length of radiator hose to run the full length from the lower outlet to the inlet on the side of the engine. The car ran fine until it got warm then the long hose began to collapse and un-collapse kinda like it was breathing. After explaining my problem to some of the experienced Model T guys in our club I ordered a steel tube and learned a lesson. I don't know why it does it but I positively know it does it.