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jeffrey8164 Samba Member
Joined: January 06, 2018 Posts: 3804 Location: Georgia
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Posted: Wed Jan 16, 2019 10:50 am Post subject: Re: CHT installation photos + too low temperature under cylinder 3 |
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According to my research and information on the Omega site one can shorten or lengthen the thermocouple wire WITH THE SAME WIRE TYPE ( That matches your thermocouple type) and connectors for that type. Wire for the thermocouple is two different types and the gauge reads the millivolt value generated by the temperature.
According to them (Omega) as long as the temperature will not exceed 500 degrees where the wire is to be used 24awg thermocouple wire is the way to go for our “short” runs.
Laugh all you want but I’ll believe the manufacturer. _________________ Volkswagen!
Turning owners into mechanics since 1938.
“Let he that is without oil throw the first rod”
(Compression 8.7:1) |
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Zed999 Samba Member
Joined: March 04, 2018 Posts: 1241 Location: UK
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Posted: Wed Jan 16, 2019 11:37 am Post subject: Re: CHT installation photos + too low temperature under cylinder 3 |
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The thermocouple works because each of the (in my case) 24" is a different composition. What the mean by the SAME WIRE TYPE for the extension is that each of the wires in the pair used is the same type, eg two copper wires. Using thermocouple wire to extend adds another cold end, a longer thermocouple, and screws up the reading.
I'm not trying to be clever, I found that out the hard way after interpreting same wire type like you are.
IF you could ensure each end of your extension was at the same temperature, I guess it would work with thermocouple wire, but why put yourself through it? |
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jeffrey8164 Samba Member
Joined: January 06, 2018 Posts: 3804 Location: Georgia
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Posted: Fri Jan 18, 2019 6:46 pm Post subject: Re: CHT installation photos + too low temperature under cylinder 3 |
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I received my method, instructions and material directly from the manufacturer. _________________ Volkswagen!
Turning owners into mechanics since 1938.
“Let he that is without oil throw the first rod”
(Compression 8.7:1) |
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UK Luke 72 Samba Member
Joined: September 07, 2011 Posts: 2867 Location: Little Britain
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Posted: Fri Jan 18, 2019 11:47 pm Post subject: Re: CHT installation photos + too low temperature under cylinder 3 |
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Zed999 wrote: |
The thermocouple works because each of the (in my case) 24" is a different composition. What the mean by the SAME WIRE TYPE for the extension is that each of the wires in the pair used is the same type, eg two copper wires. Using thermocouple wire to extend adds another cold end, a longer thermocouple, and screws up the reading.
I'm not trying to be clever, I found that out the hard way after interpreting same wire type like you are.
IF you could ensure each end of your extension was at the same temperature, I guess it would work with thermocouple wire, but why put yourself through it? |
I've got a SPA oil temp and pressure gauge on its way, I asked them.how to extend the thermocouple wire, this was their response.
Quote: |
Cable is 2 core and screen (foil wrapped with bare drain wire).
CPC = CB15208
RS = 811-7373
CPC is cheaper and they have it in stock.
If joining existing cable, you will need to solder the inner core with normal heatshrink, and then adhesive heatshrink over the whole outer cable sheath.
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No witchcraft. _________________ 2276 Beetle build https://www.thesamba.com/vw/forum/viewtopic.php?t=670744&highlight=2276+beetle+daily
2276 EFI Conversion https://www.thesamba.com/vw/forum/viewtopic.php?t=689172 |
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FreeBug Samba Member
Joined: March 12, 2012 Posts: 4278 Location: deepest, darkest Switzerland
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Posted: Sat Jan 19, 2019 12:14 am Post subject: Re: CHT installation photos + too low temperature under cylinder 3 |
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I don't understand anything about electricity, but i can say this:
-where you put the sender is fine, it's where we all have.
-you're not reading the temp correctly with your setup, the lowest cruise temps I've ever seen were around 250°F, although at 212°, maybe, just maybe...
-it's normal for the temp to climb when you stop or idle after a period of high load. Less fan rpm=less cooling.
-I totally respect Roy and totally agree that he has better, more accurate ways of measuring engine temps, but it has become the performance VW world's "industry standard", and so we can compare temps pretty much universally, across states, across countries, across continents, even if the numbers aren't really accurate But if we all start measuring at different spots, we can no longer compare anything. |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Sat Jan 19, 2019 7:04 am Post subject: Re: CHT installation photos + too low temperature under cylinder 3 |
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Zed999 wrote: |
The thermocouple works because each of the (in my case) 24" is a different composition. What the mean by the SAME WIRE TYPE for the extension is that each of the wires in the pair used is the same type, eg two copper wires. Using thermocouple wire to extend adds another cold end, a longer thermocouple, and screws up the reading.
I'm not trying to be clever, I found that out the hard way after interpreting same wire type like you are.
IF you could ensure each end of your extension was at the same temperature, I guess it would work with thermocouple wire, but why put yourself through it? |
Just go to the Omega site and educate yourself. Any advice taken from a parts counter guy or from a $30 temp gauge manufacturer is highly suspect. Once you understand exactly how a thermocouple works you will realize the value of what we are telling you.
Raygreenwood and I work with industrial/process grade temperature measurement where accuracy is mandatory not an option. If we set up our thermocouples the way some of these cheap gauge manufacturers suggest do we, we would be out of a job in a heart beat!
Thermocouples by the way are among the lowest in accuracy of modern methods to measure temperature but they are popular due to thier relitively low cost. They do require more attention to detail to get accuracy at all and the wiring type and connections are the biggest part of this required detail.
To answer your concern about wire extension type, if I recall correctly without looking it up a type K thermocouple is made up of two different metals. Iron and constantan one is jacketed red and the other yellow. The iron wire must be iron all the way to the gauge including the contact points in any connector. The same goes for the constantan side. Then and only then can you believe your gauge readings. |
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