The Ford Barn

JSeery · 08-01-2017, 09:19 PM

I haven't tried the bulb test, but the pulse rate averages around 1 sec. per a Ford manual. So you should be able to see it blink.

Note: just checked, it wasn't a Ford manual, it was in King-Seeley operation description.

tubman · 08-02-2017, 05:17 AM

Quote:

Originally Posted by JSeery

I haven't tried the bulb test, but the pulse rate averages around 1 sec. per a Ford manual. So you should be able to see it blink.

Note: just checked, it wasn't a Ford manual, it was in King-Seeley operation description.

Yeah, the Ford manual isn't very helpful; "Change it, and if it fixes it, that was your problem".

"Jseery", since you're still following this, do you think that the test would be better if I ran it at 2.7 volts rather than 6? All I had was my 6 volt battery charger that was putting out 6.3 volts. My neighbor has a variable voltage DC power supply I can borrow that would allow me to run it at 2.7 volts.

Sorry that I seem to be obsessing on this, but I just got the car together after two years, and everything else is perfect, except for the GD temperature gauge.

JSeery · 08-02-2017, 07:04 AM

If you are running the current from the source through the gauge then to the light bulb and then to the sensor and to ground, then it would be in the 6v range. If you are running just from the source to the bulb to the sensor to ground it would be in the 3v range. You are dropping half the voltage in the gauge and half in the sensor. 6v alone on just the sensor would be overloading it I would think.

B_man_Al · 08-02-2017, 07:38 AM

As JSeery suggested I think you should test through a 10 ohm resistor, or what ever your gauge resistance is, if you are going to use 6v, as the current will be too high without a series limiting resistor, or use the lower voltage without a resistor
Al

rotorwrench · 08-02-2017, 08:56 AM

Don't forget that a light bulb is also a load just like a resistor.

The indicator gauge functions just like the later types since all it has is a heater coil around the bimetallic strip that pulls the indicator needle. It can be tested by varying the current to it with a variable resistor. What range is needed would be the big question that I can't answer. Once a person knows the gauge is good then it can be used to test the senders.

The senders wear out. Even if the heating coil is good, the points can be bad or stuck in the closed switch position. One poster mentioned tapping the sender and that might work to free stuck points or it might not. Bimetallic strips generally last a long time unless some part of it cracks or comes loose. The Lincoln Mercury overhaul manual for 1949 thru 1951 has a good test procedure but it only tests for proper function. If it doesn't function then replacing the sender is the only option. I still see NOS ones on the flea-pay now and then but who knows if they work or not. Their may be a reason that the part set on the shelf for all those years.

BillM · 08-02-2017, 02:16 PM

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My recent measurements of a sender and gauge in series showed a current of about 230 ma at 6 1/2 volts and a duty cycle at room temperature of roughly 10 %; points closed.
Let's make that when the points are open; my meter reads duty cycle as a positive signal and the temperature gauge shows Cold with max current from the sender. I monitored the points with an LED and resistor in parallel with the sender. The LED blinked brightly when the points opened.
If you connected a 6 volt bulb across a sender and gauge it would lite when the points open (and maybe glow dimly when they closed). If you don't have a gauge to use a resistor of 10 or12 ohms would work or put two senders in series; but then you'd have to determine which one is switching.

langer · 07-12-2023, 07:43 PM

hey fellas... I have a 51 ford delux that i just got... all seemed to be functional and then i noticed my temp guage was pegged on H... and stays there even when the ignition is off... I'll start down the advice in this thread. do you have any other insite on why the guage would stick on H other than a bad guage... the car runs a drives very nicely and doesnt feel " too hot" to the touch...

thanks
jonah

tubman · 07-12-2023, 09:14 PM

If you have a multi-meter, check the resistance through the two terminal sender (drivers side head). It is only a swifch that opens the circuit (forcing the gauge to go fill hot) if the coolant reaches a certain high temerature If there is no resistance through it at room temperature, you've found the problem.

If that's not the problem, I seem to remember that I posted another thread on the ultimate solution; I'll try to find it.

tubman · 07-12-2023, 09:18 PM

Check out this thread : https://www.fordbarn.com/forum/showt...es#post1509023.

08-01-2017, 09:19 PM	#21
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: 1951 Temp gauge problems I haven't tried the bulb test, but the pulse rate averages around 1 sec. per a Ford manual. So you should be able to see it blink. Note: just checked, it wasn't a Ford manual, it was in King-Seeley operation description. Last edited by JSeery; 08-01-2017 at 09:32 PM.

08-02-2017, 07:04 AM	#23
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: 1951 Temp gauge problems If you are running the current from the source through the gauge then to the light bulb and then to the sensor and to ground, then it would be in the 6v range. If you are running just from the source to the bulb to the sensor to ground it would be in the 3v range. You are dropping half the voltage in the gauge and half in the sensor. 6v alone on just the sensor would be overloading it I would think.

08-02-2017, 07:38 AM	#24
B_man_Al Senior Member Join Date: Feb 2011 Location: Ottawa ON Canada Posts: 301	Re: 1951 Temp gauge problems As JSeery suggested I think you should test through a 10 ohm resistor, or what ever your gauge resistance is, if you are going to use 6v, as the current will be too high without a series limiting resistor, or use the lower voltage without a resistor Al

08-02-2017, 08:56 AM	#25
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: 1951 Temp gauge problems Don't forget that a light bulb is also a load just like a resistor. The indicator gauge functions just like the later types since all it has is a heater coil around the bimetallic strip that pulls the indicator needle. It can be tested by varying the current to it with a variable resistor. What range is needed would be the big question that I can't answer. Once a person knows the gauge is good then it can be used to test the senders. The senders wear out. Even if the heating coil is good, the points can be bad or stuck in the closed switch position. One poster mentioned tapping the sender and that might work to free stuck points or it might not. Bimetallic strips generally last a long time unless some part of it cracks or comes loose. The Lincoln Mercury overhaul manual for 1949 thru 1951 has a good test procedure but it only tests for proper function. If it doesn't function then replacing the sender is the only option. I still see NOS ones on the flea-pay now and then but who knows if they work or not. Their may be a reason that the part set on the shelf for all those years.

08-02-2017, 02:16 PM	#26
BillM Senior Member Join Date: May 2010 Location: Everett, WA Posts: 504	Re: 1951 Temp gauge problems Sponsored Links (Register now to hide all advertisements) My recent measurements of a sender and gauge in series showed a current of about 230 ma at 6 1/2 volts and a duty cycle at room temperature of roughly 10 %; points closed. Let's make that when the points are open; my meter reads duty cycle as a positive signal and the temperature gauge shows Cold with max current from the sender. I monitored the points with an LED and resistor in parallel with the sender. The LED blinked brightly when the points opened. If you connected a 6 volt bulb across a sender and gauge it would lite when the points open (and maybe glow dimly when they closed). If you don't have a gauge to use a resistor of 10 or12 ohms would work or put two senders in series; but then you'd have to determine which one is switching. __________________ My web page: http://myplace.frontier.com/~wgmumaw/ Last edited by BillM; 08-02-2017 at 08:35 PM. Reason: Duty cycle correction.

07-12-2023, 07:43 PM	#27
langer Junior Member Join Date: Jul 2023 Location: The Pacific Northwest Posts: 1	Re: 1951 Temp gauge problems hey fellas... I have a 51 ford delux that i just got... all seemed to be functional and then i noticed my temp guage was pegged on H... and stays there even when the ignition is off... I'll start down the advice in this thread. do you have any other insite on why the guage would stick on H other than a bad guage... the car runs a drives very nicely and doesnt feel " too hot" to the touch... thanks jonah

07-12-2023, 09:14 PM	#28
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,320	Re: 1951 Temp gauge problems If you have a multi-meter, check the resistance through the two terminal sender (drivers side head). It is only a swifch that opens the circuit (forcing the gauge to go fill hot) if the coolant reaches a certain high temerature If there is no resistance through it at room temperature, you've found the problem. If that's not the problem, I seem to remember that I posted another thread on the ultimate solution; I'll try to find it. Last edited by tubman; 07-12-2023 at 09:27 PM.

07-12-2023, 09:18 PM	#29
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,320	Re: 1951 Temp gauge problems Check out this thread : https://www.fordbarn.com/forum/showt...es#post1509023. Last edited by tubman; 07-12-2023 at 09:26 PM.