Looking to add temp gauge to LA150

[Hammermechanicman]

Usually get to them with a crowsfoot wrench.

 

[Ken22]

During the winter, I'm gonna be pulling the engine (Briggs 24HP twin) due to the oil sump gasket leaking badly. I'm gonna inspect and reseal the engine as well as take care of maintenance it needs as the tractor has +/- 600 hours on it and I know not all of the required maintenance has been done on it.

Although the engine is air cooled, I've been thinking I'd like to add a temperature gauge because I'd like to keep an eye on it. It hasn't been acting as if it's running hot at all, but since I'm gonna have the engine out and disassembled, I figured it's as good a time as any to add one. I was wondering if anyone has added a gauge to one of these engines, where you installed the sensor, and what brand sensor/gauge did you use? I've found plenty of sensor/gauge kits for water cooled models but they include sensors intended to be mounted in a cooling passage. I did find a head temp sensor that would be very easy to install (https://www.amazon.com/Cylinder-Hea...instruments+temp+sensor&qid=1604018011&sr=8-5) but it doesn't include a gauge and I'm not totally sure what it would need. My experience is with negative temp coefficient sensors but I haven't yet found time to determine if that's what this sensor is.

I was also curious if there's any other suggestions for what I should do while the engine is out. I'm planning to replace the steering shaft gear as it's stripped and the front spindles as they are worn. The tractor is in overall good condition, it just needs a little TLC.

I'm a professional auto mechanic and we also do plenty of small engine work at my shop so I'm not at all intimidated by anything on this mower - just need some tips and suggestions.

Thanks.

For your reader search for "K type thermocouple reader" Amazon.com has one for $10.49

 

[Gumby83]

Needed clarification on this since I’ve narrowed down one of 2 ways I want to set up the temp gauge.

The preferred option is the CHT sensor. Since the engine has 2 cylinder heads, do I have to have 2 separate gauges, or can I wire 2 sensors into one gauge? I realize that may only provide an average reading of both heads, which I’m fine with, but if it won’t work, I’m not interested in setting up 2 separate gauges.

The second option is to monitor oil temp - location for the sensor TBD.

Thanks.

 

[Gumby83]

So I put my search engine skills to the test and finally figured out that wiring 2 CHT sensors (type K thermocouples) in parallel will work on one gauge, but for the most accurate measurement, it’s important that the circuit resistance for each thermocouple is the same, as well as the materials used to make the thermocouple and wire. I also learned that a resistor can be added to each branch of the circuit to compensate for minor variations in circuit resistance due to different lengths of wire where the splices are made.

During my research, I found these 2 websites to be the most useful.

Thermocouple operation, types, and temperature to voltage correlation charts -https://www.thermocoupleinfo.com/

How circuit configuration affects thermocouple performance (this site is full of technical info - I plan to do more reading here when I have the time) -https://www.allaboutcircuits.com/textbook/direct-current/chpt-9/thermocouples/

Thanks again to all who contributed to this discussion.