I do feel I have posted far to many questions recently and not given much advice back but I hope to as I get to understand my T better.
I have a Motometer fitted to my car ( I know they can divide opinion ) anyway since having it fitted I have noticed that if I'm stationary it registers about half way, and when running certainly in cooler weather the temp actually plummets and hardly registers if at all.
This suggests to me that my car is running quite cold and therefore less efficient and causing more wear, I thought I could slacken off the belt that drives the fan or maybe remove completely if it's cooler say in the 50&60 fair Spring temp in uk warmer today though.
Does anyone have any experience of doing this?
A better solution is to make a cardboard cover for the lower 1/4 of the radiator. The fan will make no difference when driving.
Some will chime in saying you don't need a fan at all. Others will say it's absolutely needed. I'll say, that's why I don't have a motometer. Too much information. It it's boiling, I'll know it. If it isn't, I don't care.
Be fortunate your T doesn't overheat, as many do, and don't worry about it. It sounds like a normal T, running well and cooling properly.
And, some will say, use cardboard. Forgot that one, sorry Royce. ;O)
Assuming you do not have a water pump (God forbid), IMHO you're worried about nothing. The thermosiphon cooling system is pretty much self controlling. The engine heats the water/coolant. It rises and moves to the upper radiator tank. It then travels down through the tube to the lower tank, cooling as it moves. It then it's siphoned back into the engine, and does it all over again. The hotter the engine the faster it moves. The cooler the engine the slower it moves.
I'd check the calibration on the Mometer.
There's no such thing as too many questions. Most of us old T guys like to talk and give free advice. It's sort of a therapy.
I checked the Motometer previously it is correctly calibrated, I think I am just worrying about something that is probably not a problem! T seems to run well and quick so I'm going to stop worrying now!
This forum is great I have learnt so much with nobody nearby have been able to diagnose, fix and sort problems by coming on here and asking a question, it genuinely is a fantastic forum.
TT, Define "cooler" weather? What type of temperatures are you driving in when the meter does not register? Can you get a hold of a regular candy making, or cooking thermometer to place into the radiator neck to find out the real temperature? I do not know how accurate the motometer is supposed to be since a Modell T radiator at proper level has the fluid right above the baffle and the Motometer lower tip is really up in the air......or in the steam!
I choose to run a home-made cardboard winter front that covers the lower third of my radiator when the temperature is below 40 degrees F. The rest of the time I leave it off and let the thermosiphon do its thing.
In response to a couple of questions
The Motometer calibrates nicely with steam only which seems to be the sensible way as this is how it sits in the radiator.
The temp has been around the 50-60 mark over last couple of weeks, registers when ticking over only when driving does it drops considerably probably meaning the radiator and system is efficient!
It's a standard set up no pumps etc, I like the back to basics approach!
I might have a play with a small outside cover to slow the cooling air coming in whilst driving just to see how it reacts, I think if it's running a little warmer it's likely to be more efficient
As Mr. Petrino stated, a thermosiphon cooling system is virtually self regulating. The hotter the water gets, the faster it will circulate. You really shouldn't need a cardboard front nor should you need to remove the fan belt. It should be fine just like Mr. Ford designed it. A Motometer is just an accessory that looks nice. You will know if your car runs hot, and you will not notice any loss of efficiency if it is running cool and I don't think it would contribute to increased wear.
I'm currently running with a Peerless honeycomb radiator and no water pump. From time to time ... after say a 2+ hour drive ... I lift the hood and feel the water return pipe. Then I feel the upper radiator tank. Not quite sure what I'm looking for but I think it's generally good that the pipe is warm ... and the tank is hot. Some day I would like to install a thermometer in the intake elbow and see how warm the water going back into the engine actually reads.
The fan is useful for idling and or slow traffic, parades etc. Driving will cause more air to go through the radiator than the fan causes. The problem with removing the fan is that you might get stuck in traffic and overheat. If you have a crank start car, you cannot turn off the engine unless you get out in traffic to start it up again.
The cardboard method will work very well in cold weather. Also you might try the motometer on another car. Sometimes one motometer reading is different from another. I think the motometer is an interesting ornament and it will also give you some idea whether you are overheating, but it is not 100% accurate.
I have one on both of my Model A s and to start with I spent time worrying about where they read but after years of driving them they it seems at 60 degrees just at the bottom of the motometer. @ 90 mid way. The motor on my 27 model T reads the same and the other has a standard cap. Just my experience Tim
Some time ago (before retirement)I remember dicussions about partially covering the radiator on engines where the fan is close to the radiator. As the blades passed by the blocked portion of the radiator the loading on the blade changes causing it to flex which could lead to fatigue failures. I was involved with a fleet so we weren't talking about T's but I think it might apply.
Volvos OF THE 1950'S CAME WITH A BLIND YOU COULD ADJUST UP AND DOWN. Sorry caps lock was turned on when I capitalized Of the 1950's.
Something easily removable like the partial cardboard cover is your answer. If you need the fan at some point just pulling it off beats messing with the belt or worse having to re-install the fan.
The adjusting blind was used on most cars in Sweden during the 1940's through the 50's, it's likely the importers added it on foreign cars like Opels and Fords. Eventually when ethylene glycole got more commonly used as a antifreeze, the radiator didn't have to be protected from the cool air stream when starting to drive a cold car in wintertime, and the thermostat could be relied on as the only regulator in the system.
Actually you can use a thermostat in a thermosyphon system too - I've used one in my pickup with no negative effects - it speeds up the warm up time and that should reduce wear, engines wear most rapidly when cold.
No, I don't have any fan either, traffic is so thin around here so I'll take the chance of having to crank it up again, should I ever get stuck in traffic more than a minute or two (that it can handle)
A cardboard cut out it is 😀