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Author Topic: head temp sensor  (Read 192 times)

chefiam1

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head temp sensor
« on: January 15, 2020, 04:29:55 PM »
Chef here again, where would i get a drawing  of how to wire the sensor up.
two wires cannot be that hard. what i have it shows it going to the oil pressure switch but,i don't have an oil pressure switch. unless they both are inside the temp sensor?all help is welcomed. building the motor had directions. now i'm
stuck on little things that has become big thinks! i would like to start this machine i guess it's called patience!!

                                                 thanks, chefiam

cobbadog

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Re: head temp sensor
« Reply #1 on: January 16, 2020, 05:53:37 AM »
Keep on asking the questions as needed. This switch looks like an engine temperature switch and if it is all you need to do is run a positive wire to one side of the switch the other side of the switch to one side of the gauge then the other side of the gauge to ground.
Again it is a nice clear picture of the switch but I cannot begin to guess where abouts on the engine it is. Some engines can get both oil pressure and engine temp from the head so more details lease for an accurate reply.
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snowman18

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Re: head temp sensor
« Reply #2 on: January 16, 2020, 04:27:26 PM »
Temperature Murphy would be ( NC ) normally closed, breaks circuit at critical temperature closing fuel solenoid.

Oil pressure Murphy normally open ( NO ) engine has to crank over to build pressure to close the internal contacts to complete the circuit, often an engine equipped with a oil Murphy will have a push button switch to complete  the Murphy circuit during start up.

Below is a over heating protection Murphy on my Wisconsin air cooled engine.



« Last Edit: January 17, 2020, 05:32:26 AM by snowman18 »

cobbadog

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Re: head temp sensor
« Reply #3 on: January 17, 2020, 03:26:33 AM »
Nice one, I have seen these Murphy gauges on forklifts in high temps around a furnace but never knew how they worked, thanks.
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snowman18

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Re: head temp sensor
« Reply #4 on: January 17, 2020, 05:22:31 AM »
Nice one, I have seen these Murphy gauges on forklifts in high temps around a furnace but never knew how they worked, thanks.

Welcome.

I'm familiar with the thermal disks used in electric furnace, the old style wall thermostats and cloths dryers.

The Wisconsin has a coil ignition, I'm guessing the Murphy used has bi metal strip inside should the engine reach a critical operating temperature. The bi metal strip inside the brass block bends enough to short out the ignition system and will not allow a restart until the engine has cooled down.

This Murphy is secured against the cylinder head with a head bolt.

This wiki explains them and their uses.

https://en.wikipedia.org/wiki/Bimetallic_strip

« Last Edit: January 17, 2020, 05:33:43 AM by snowman18 »

cobbadog

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Re: head temp sensor
« Reply #5 on: January 17, 2020, 10:13:20 AM »
Cheers snowman, I enjoy learning new stuff that is of interest, thanks.
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chefiam1

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Re: head temp sensor
« Reply #6 on: January 17, 2020, 11:22:53 AM »
Snowman, that is exactly what i have !! could not figure out how the temp sensor
and oil were connected along with the fuel shut off. i thought i had a bad cht but , that stays n/c then when the temp reaches a certain point it opens and cut the fuel off. did i get it right snowman? thanks again.

                                                       chefiam1

chefiam1

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Re: head temp sensor
« Reply #7 on: January 17, 2020, 11:29:58 AM »
now since i pulled the cht out puting it back it needs to be grounded.
so what type of sealant should i use on cht threads so it seals and still stays grounded. or will it be grounded enough just using any thread sealant?
                                                     thanks, chefiam

snowman18

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Re: head temp sensor
« Reply #8 on: January 17, 2020, 04:54:37 PM »
Snowman, that is exactly what i have !! could not figure out how the temp sensor
and oil were connected along with the fuel shut off. i thought i had a bad cht but , that stays n/c then when the temp reaches a certain point it opens and cut the fuel off. did i get it right snowman? thanks again.

                                                       chefiam1

Spot on,

Domestic Electric hot water tank has a pair of thermally operated rheostats, these you can adjust to either raise or lower the water temperature.

I used one to control the temperature of hot vegetable oil being circulated through a double walled glass reactor. The thermal switch was inline to the circuit which supplied power the heating element.

In a circuit using this type of rheostat, element could be fuel pump.

The glass reactor was used for refining metals and the reaction required a lot of heat, I used oil rather than water to transfer that heat.

The bottom image, often used in automotive , riding mower etc commonly found in the charging circuit..



« Last Edit: January 17, 2020, 05:28:14 PM by snowman18 »