WTB 1973 Cylinder Head Temp sensor p/n 017, Looking for original temp sensor Options

[Superhawk996]

WTB 1973 Cylinder Head Temp Sensor

Part number 0 280 130 017: about 1.3 K ohms at 68 deg - supposedly unique to 1973 only for use in conjunction with the 270 ohm external resistor.

Anyone have a verified good part?

[Superhawk996]

Not a bad suggestion on the surface.

However, resistance of the thermocouple that is at the heart of the sensor often isn't linear. Adding a resistor is linear.

Using the information below:

If you ad the 890 ohms of difference between the 012 part number CHT sensor and the 017 CHT sensor part, to get to the same resistance at ambient temperature, it will also add 890 ohms to the warm resistance which will be way to much resistance when hot.


Sensor:
Temp @ 39 deg. Temp @ 61 deg. Temp @ 210 deg F

0 280 130 003 6.10 K ohms 2.94 K ohms 199.3 ohms
0 280 130 012 NA .85 K ohms 191.2 ohms
0 280 130 017 3.63 K ohms 1.74 K ohms 124.7 ohms

from https://members.rennlist.com/pbanders/DJetParts.htm

If we had all three sensors, you could generate plots with many more points than just these 3 and it would obvious that the resistance change per degree of heat change isn't linear.

I've read of others using variable potentiometers to adjust the resistance manually as the engine warms but that is just a very bad band aid.

I could create some sort of program on an Arduino microprocessor to mimic the non-linear effects but again that is just a lot of work to create a band aid.

I still think it should be easier to find a CHT sensor - even if used but then again, this WTB ad has only been up for a day. (IMG:style_emoticons/default/biggrin.gif)