The Ford Barn

Ed in Maine · 06-29-2018, 03:09 PM

I also was not satisfied with the temperature measurement for my Model A. My motor meter did not measure temperature accurately. I did some research on the internet and tried the following two schemes:
Measure Temperature with the transistor LM34. This semiconductor is tiny with three leads coming out of it. You can connect to it a resistor and a 9 v battery. Then with a digital volt ohm meter you can measure the millivolt signal coming from the transistor which is linear with changes in temperature (F) from -50F to 300F. It is accurate to ½ F. I used very small wire (24-26 ga.) wire and fed it out of the radiator in the over flow tube into the engine compartment, then behind the kick panel inside the car. I use it as a test device not as an operational temperature monitor because I never figured out how to shield the sensor from the RF from the ignition. The readout jumps all over when the engine is running!
Measure Temperature with the Taylor Digital Thermometer #3516. This is the kind of digital thermometer that you use to measure the temperature of a roast beef. It disassembles easily so that you can mount the circuit board and digital read out into a Motormeter. They are less than $10.00 and are very accurate and while the read out is small it can be seen from inside the car. The Problem: The thermometer has an “auto off” feature which turns off the thermometer after 10-15 minutes. You have push the On button again to turn it back on. I couldn’t figure out how to defeat this feature and no one at Taylor Instrument could tell me either. Maybe someone at Ford Barn could figure out a fix. I enjoy playing with little projects like this. Ed

06-29-2018, 03:09 PM	#23
Ed in Maine Senior Member Join Date: May 2010 Location: Washington Cty., ME or Flagler Cty., FL Posts: 1,223	Re: Temperature Gauge I also was not satisfied with the temperature measurement for my Model A. My motor meter did not measure temperature accurately. I did some research on the internet and tried the following two schemes: Measure Temperature with the transistor LM34. This semiconductor is tiny with three leads coming out of it. You can connect to it a resistor and a 9 v battery. Then with a digital volt ohm meter you can measure the millivolt signal coming from the transistor which is linear with changes in temperature (F) from -50F to 300F. It is accurate to ½ F. I used very small wire (24-26 ga.) wire and fed it out of the radiator in the over flow tube into the engine compartment, then behind the kick panel inside the car. I use it as a test device not as an operational temperature monitor because I never figured out how to shield the sensor from the RF from the ignition. The readout jumps all over when the engine is running! Measure Temperature with the Taylor Digital Thermometer #3516. This is the kind of digital thermometer that you use to measure the temperature of a roast beef. It disassembles easily so that you can mount the circuit board and digital read out into a Motormeter. They are less than $10.00 and are very accurate and while the read out is small it can be seen from inside the car. The Problem: The thermometer has an “auto off” feature which turns off the thermometer after 10-15 minutes. You have push the On button again to turn it back on. I couldn’t figure out how to defeat this feature and no one at Taylor Instrument could tell me either. Maybe someone at Ford Barn could figure out a fix. I enjoy playing with little projects like this. Ed