Track Tac

mychron 4 temp thermocouple brokern

i have one that i stripped and rewelded internal wires back together and reattached plug ring to it this past week but have not had time to test it yet I will post results this weekend
 
Tig welder will fix the end of the temp lead that usually breaks off, or aluminum brazing rod. I took mine to the local vocational school or technical college as some call it, and the students there fixed it for me
 
^ Really?

Now I'm going to have to try this.
Got one torn up in a crash last week and already threw it out....DOH!

Thanks,
Brian Carlson
 
Thermocouples are made from two different type of wires, that is what causes it to emit a voltage when heated up. The thermocouples used for karts are made the same way except the end of the thermocouple is then place in or connected to a ring around the spark plug, where the thermocouple is attached is where the temp is being measured. Some times the weld of the two different wires come apart at the weld of those two wires, that has to be re-welded then it has to be reinserted back into the ring that goes under the plug. Other times the thermocouple its self becomes corroded where its attached to the ring or breaks there that is the easiest fix, just remember where ever you attach the end of the thermocouple that is where the temp is being measured.
Just keep in mind wherever those two different wires first touch each other(the thermocouple junction) is where the temp is being measured.
 
so...if the soft uninsulated wire lead going to the washer breaks at the washer, could you make a loop with the wire lead and attach it with a bold to the head to register temperature?
 
You could twist the ends of both wires together and where they first touch each other that is where they will registrar the temp change, how well the or accurate the reading would be is questionable. The reason they use a washer around the plug is in that area it more thin and consistent place for a reading. If you are only looking for a reading to use as a reference for you to go by then it doesn't matter how accurate it is to the true head reading.
When I use to make hundreds of thermocouples and would find a broken weld on the end of one of the thermocouples, I would strip a new section where I wanted to weld it back together twist those ends together, take the other ends and twist them together and using a vice grip fasten that end to a car battery, and then take the end twisted together that I wanted welded and touch it to the opposite battery terminal for a splt second and it would spot weld them back together.
Fastening it to the head with a bolt thru the loop on the end using a washer after its twisted together will work but it will be measuring the temperature in that area which may not be the best spot to see what the engine is doing.
 
Just twisting thermocouple wires together you have to consider that corrosion will start(because of dissimilar metals) quickly and could cause the readings to quit or not be accurate. That's why in most cases they recommend welding the ends together. The thermocouples used with the washer around the spark plug is really reading the temp that the washer is because that is where the thermocouple is fastened but that is still most likely the more sensitive and true place to get a reading, around the head elsewhere is not the best because of the cooling fins.
 
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