Temp Sensor Ohm Information
Thread Starter
Le Mans Master
Joined: Aug 2000
Posts: 9,662
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From: Semper ubi, sub ubi
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Temp Sensor Ohm Information
I'm preparing to to try and find a replacement for my temperature sensor for my 69 SB, that won't fit in my new Vortec heads. I took the old sensor and suspended it in boiling water and obtained a reading of 2650 Ohms, then I placed in a cup of crushed ice and water (my thermometer said it was 0* C.) the reading was 1150 Ohms.
Has anyone found a new smaller temp sensor that fits anywhere close to this range?
I sure wish that there was someplace that we could get a cross reference for these things!
Has anyone found a new smaller temp sensor that fits anywhere close to this range?
I sure wish that there was someplace that we could get a cross reference for these things!
Le Mans Master
Joined: Sep 2000
Posts: 5,635
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From: Orlando Floriduh
Re: Temp Sensor Ohm Information (Smokehouse69)
Do a search on http://www.ncrs.org archives. There is a whole lot of info about calibrating the gauge and various senders.
BTW your heat riser is on the way :cheers:
[Modified by silvervetteman, 6:43 PM 2/3/2002]
BTW your heat riser is on the way :cheers:
[Modified by silvervetteman, 6:43 PM 2/3/2002]
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
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From: Twin Cities Minnesota
Re: Temp Sensor Ohm Information (Smokehouse69)
I searched the entire temp sensor catalog at my favorite partshouse. nothing was even close! :mad
I ended up putting the temp sensor in the water neck hole...
The water temp is a little hotter there ( 10 degrees ?) since it's after the heads rather than before it, but it works!
I ended up putting the temp sensor in the water neck hole...
The water temp is a little hotter there ( 10 degrees ?) since it's after the heads rather than before it, but it works!
Instructor
Joined: Aug 2000
Posts: 177
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From: Toledo,Ohio,USA
Re: Temp Sensor Ohm Information (Smokehouse69)
I'm not sure if my 74 uses the same ohm rating on the temp sender as your 69, but I had the same problem with the fast burn Vortec heads I used. I was never able to find the smaller sending unit with the correct ohm rating. I ended up using a sender with a lower ohm rating and added a in line ceramic resistor that bought my resistance back in line , my gauge is very close now. The ohm ratings the spec books go by are much lower than what you are getting(not sure at what temp. they are taken) if I remember correctly my stock 74 unit was between 78 and 82 ohms and I used a 42 ohm sending unit and added two 20 ohm resistors. I just spliced them into the wire coming from the sending unit and used black wire loom tape to cover them, pretty hard to spot unless your looking for them. I don,t recall the part# of the sender I used but I kept the box, which I can dig out if you need it.
Le Mans Master
Joined: Sep 2000
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From: DFW TX
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St. Jude Donor '07
Re: Temp Sensor Ohm Information (74ZZ430)
Smokehouse,
I'm using an 82 vette sensor and it's pretty darn close. I install a safety back up under the hood and it seems to run inline with it. I have shearched high and low, no one makes a 1/2" sensor with the earlier ohm range.
Budman
I'm using an 82 vette sensor and it's pretty darn close. I install a safety back up under the hood and it seems to run inline with it. I have shearched high and low, no one makes a 1/2" sensor with the earlier ohm range.
Budman
Melting Slicks
Joined: Apr 2001
Posts: 3,399
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From: Olmsted Falls, Ohio
Re: Temp Sensor Ohm Information (Smokehouse69)
If the heads are off, just drill out that 3/8 NPT hole with a 23/32" drill and tap with a 1/2-14 NPT. That way hunting for a "close" replacement sensor never comes up again. I did it on my Torquer's driver's side head and left the 3/8 NPT on the passenger side for the electric fan sensor.
Thread Starter
Le Mans Master
Joined: Aug 2000
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From: Semper ubi, sub ubi
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Re: Temp Sensor Ohm Information (Budman78)
Thanks for the information guys, I think I'll try several of your suggestions. I wish I had tried to get the heads drilled and tapped before I bolted them on, but worrying about the temp sensor was an afterthought. I'll get a sensor from an 82 'vette, and install a seperate mechanical gauge under the hood. Then I'll put my old sensor up in the water-pump neck. That way I can try switching from the two locations, while it is running.
