50 flathead V8 temp. sending units

J

johndob1929

Junior Member
can anyone tell me if the stock sending units (one in each head) on my 50 flathead V8 (one has 2 wires on it and one has one wire but the wires were cut right at the sending units) are for a dummy light or will they run a old electric temp. gage ? i want to run the old electric temp. gage. do i need special sending units (if so, what am am i looking for ?). how do i wire them ? i am still using the original 6 volt, positive ground system. thanks - john
 
Run a wire from the sender with the single terminal to one of the terminals on the dual post sender and then a wire from the other terminal to the gauge. if everything is good, it will work.
 
The single-pole sender provides variable resistance as the temperature rises and falls, thus sends the reading to your gauge. The two-pole sender is an on/off unit which when closed, is a pass-through device, sending the resistance feed from the single-pole sender on to the gauge. When it senses an overheat condition, it goes open, breaks the circuit, and the gauge will indicate full-on hot. Kinda Mickey Mouse, but it works pretty well on a motor with two separate cooling systems. An alternative is to install two of the single pole sensors and a L/R switch so each head can be individually monitored. Or use a dual readout gauge and senders from someone like Westach.
 
I agree with TStiles. The water temp indicating system is a bit strange. It works if all the components are right. You can wire two single pole units through a double pole switch to see the temp on each side of the engine. Be aware the after market single pole sensors work per the description in the '53 owners manual. That states something top like "normal indication is below hot". In my '53 six and '41 V8 the indicator sits over the last graduation before the H. So if it is in an over heat condition the pointer move less than an 1/8". So much for high visuals.:rolleyes:
The attached shows the original set up.
 

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I didnt know these engines use electrical temp sensor I thought it was the bulb type that has a thick heat conducting wire that runs to the needle on the guage. I dont know if that worked but it's a picture of a mechanical temp guage.

water_temp_gauge.htm
 
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There is some bad information in this thread! The KS gauge system does not work on resistance like a modern sender would. They are a current pulse system. The power is input to one terminal of the dash gauge, the other terminal is connected to the sender on the head that has two terminals. The other terminal on the sender goes over to the single terminal sender on the other head. The current flows from the power source through the dash gauge which has a coil that heats up a bi-metal strip that moves the gauge needle. Then through the two terminal sender which in normally closed below a set temperature (it is an on/off switch) on to the single terminal sender. The single terminal sender has a set of points that pulses in relationship to the engine temperature. The rate of this pulse determines the current flow in the circuit and thus the amount of heat in the gauge coil. It works the same on 6v or 12v and will work with ether polarity (+ or - ground). But it does need a voltage drop at the input to the dash gauge. When Ford switched to 12v systems they kept the same type of gauges and senders and added a voltage drop unit. One option is to use the voltage drop off of a later 12v Ford or some prefer other drops that are available. A diagram was posted in #4.
 
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JSeery said:
There is some bad information in this thread! The KS gauge system does not work on resistance like a modern sender would. They are a current pulse system. The power is input to one terminal of the dash gauge, the other terminal is connected to the sender on the head that has two terminals. The other terminal on the sender goes over to the single terminal sender on the other head. The current flows from the power source through the dash gauge which has a coil that heats up a bi-metal strip that moves the gauge needle. Then through the two terminal sender which in normally closed below a set temperature (it is an on/off switch) on to the single terminal sender. The single terminal sender has a set of points that pulses in relationship to the engine temperature. The rate of this pulse determines the current flow in the circuit and thus the amount of heat in the gauge coil. It works the same on 6v or 12v and will work with ether polarity (+ or - ground). But it does need a voltage drop at the input to the dash gauge. When Ford switched to 12v systems they kept the same type of gauges and senders and added a voltage drop unit. One option is to use the voltage drop off of a later 12v Ford or some prefer other drops that are available. A diagram was posted in #4.
Click to expand...
I like your explanation but what is a "KS gauge system"? Since I have power leading to my gauge, I assume it a is a KS system. Correct? Thanks.
 
41ford1 said:
I agree with TStiles. The water temp indicating system is a bit strange. It works if all the components are right. You can wire two single pole units through a double pole switch to see the temp on each side of the engine. Be aware the after market single pole sensors work per the description in the '53 owners manual. That states something top like "normal indication is below hot". In my '53 six and '41 V8 the indicator sits over the last graduation before the H. So if it is in an over heat condition the pointer move less than an 1/8". So much for high visuals.:rolleyes:
The attached shows the original set up.
Click to expand...

41ford1
Your attachment shows the wiring diagram for the temperature sensors. On it the diagram shows that contact opens at approximately ? temperature. I am unable to read what the temperature is. Do you have the original to tell me what that number is?
I have a 1950 shoebox and have been running a actual temperature gauge for each head after a rebuild. The temperature runs anywhere from 190 to 210 degrees on each head while driving. I have now installed new factory sensors and it is running in half way between cold and hot. I haven't run it much since. I was wandering at what temperature the double contact opens to send it to hot.
 
1950 custom said:
41ford1
Your attachment shows the wiring diagram for the temperature sensors. On it the diagram shows that contact opens at approximately ? temperature. I am unable to read what the temperature is. Do you have the original to tell me what that number is?
I have a 1950 shoebox and have been running a actual temperature gauge for each head after a rebuild. The temperature runs anywhere from 190 to 210 degrees on each head while driving. I have now installed new factory sensors and it is running in half way between cold and hot. I haven't run it much since. I was wandering at what temperature the double contact opens to send it to hot.
Click to expand...
124005
 
The double contact sender unit opens at about 200 degrees.
I know this is correct because I just installed brand new OEM temp sender units and then checked them with a laser temp gun and a continuity tester.

If you touch one probe of the continuity tester to one of the temp sender terminals and the other probe to the other temp sender terminal the continuity sender will "beep" indicating that the internal points of the temp sender are closed. When the temp sender internal points open there will not be a "beep" indicating the internal points have opened. At that point the King Seeley gauge needle goes to Hot.

Go to www.fordbarn.com and do a search on Temperature sending unit. Tons of info.
 
Thanks for the information but if mine are the same which they should be, the two manual gauges i had in were always reading wrong. Like i said they both showed it running anywhere from 190 to 210 degrees. Now with the factory sensors and gauge it is running about midway between cold and hot. Looks like i need to do some more testing.
 
Please post photos of the temp sender units and two manual gauge units you are using.

Are all the components you are using OEM 1950 Ford components?

The Ford temp sender units will only work with the OEM temp gauge units. Both were made by King Seely. Other after market gauges won't work.
 
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