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?

The Bosch 017 is also VW 022 906 041A. The 017 is designed to work with a 260 ohm resistor. It was used only on the 2.0 for 1973

May have a used one. Have to check. Afermarket ones patterned after 017.

@914Sixer

I didn't expect to find a new one given that these were only used on 1973. PM me if you find one.

Unfortunately my car is 1973 and I was thinking of going back to all OE. I am aware that others convert to the 74 ECU, dizzy, etc. so that they have wider part choices.

My understanding is that there was quite a difference between the other sensors and the 017 at ambient temp (1973 only). Something on the order of 1000 ohms at ambient. Does anyone know what the resistance is of say the 914Rubber CHT sensor at ambient vs. the 017?

I didn't think aftermarket sensors would work on 1973 systems even with the 250 ohm resistor in place.

Thanks!

The 017 is definitely different from the 012 sensor which are commonly available. You can use a 012 sensor and your engine will run decent but definitely not as it should with the 017. Mainly the warmup enrichment will be off.

I’d reach out to 914Rubber to see if they can make them. I inquired a year or two ago when I was in the same boat as you.

Why not just find the difference in resistance and add a resistor to the 012 sensor if it's widely available?

Just checked the resistance of a brand new 914 Rubber temp sensor and a URO temp sensor at 73 degrees room temperature.

914 Rubber
2160-2180 ohms @73*


URO
2002-2004 ohms @ 73 *

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.

Bummer -- neither of them look to be the same as the mythical 017 CHT sensor.

My 017 p/n measures 2.86K ohms at ambient which leads me to believe it is bad since the table of values I just posted shows that is should be more like 1.74K ohms.

Thank you for looking

Can't believe no one has one of these sitting around just rotting away on a 1973 GA engine in the back of the parts pile.

Anyone?

Why would the resistance not be linear? I've never seen a temp sensor that isn't.

https://www.ratwell.com/technical/TempSensorII.html

Aren't these things effectively ignored after the head is warmed-up?

I'd suggest the performance difference of these two sensors is basically undetectable. And, the higher resistance of the 012 might actually improve the warm-up cycle of the '73, telling the computers it's "colder" than it actually is.

I'd toss the common one on and be done with it.

? ? Not sure what you mean. The graph of the temp sensor in the link you provided clearly shows the non lineararity.

Great link though!!

PM sent

Kevin is the man of the hour. Thank you for helping!!

Part is used and unknown whether it's working or not. I'll check out when I receive it and will post a graph of temperature response if it is working so others have access to the sensor response characteristics that seem to be lacking on the 017 CHT sensors used in 1973 only.