I am swapping to the ZZ4 motor soon. As mentioned in other posts, the stock water temp sensor will not screw into the head of the new motor, different size hole.

Will any sensor or any GM sensor work with the stock gauges? I would think that these work on resistance and there would be some type of standardization (sp?).

Any suggestions on this? I don't want to have to put the temp sensor in the intake as that would look like :U on a new engine.


[Modified by BSeery, 2:52 PM 9/5/2001]

 

I hope someone has the answer to your question, I also swapped my engine I called everyone i know and even the GM in Arizona where i bought my engine and of course they were no help, i had to make an adapter for the sensor, but i dont think it works to well.
So if anyone knows what type or part number we can replace it with or what resistance it is please let us know.
Thanks
Ray

 

I'm in the same situation also! :yesnod:

 

I put a ZZ4 in my 71 about 5 month ago and everything went fine but the temp sensor. I have tried 3 of them from GM and none of them have been right. I got so fustrated that I finally put the old one in the intake. Check out my post called "button" connectors from a few days ago. I used a Rayteck IR temp gun for the first few months to check my temp and the engine runs at around 180 degrees. I am taking the latest sensor back the my local Chevy dealer for a refund. It cost 28 bucks!!. I am tired of searching for the proper sensor and am going to run my old one (ordering a new one this week..again see my other post for details) in the intake. The Rayteck indicates that it runs about 5 to 10 degrees cooler than the head location. Why can't somone make a small diameter sensor for our older cars? I guess if you wanted to you could have the head tapped and threaded but I just can't make myself do that to a brand new engine. Maybe when I install the Hot cam in a few years.
John

P.S. If you find one that works PLEASE give me the P/N and also check out my post on Sallee-Chevrolet's discussion board titled water temp snesor for 71 vette. This is the latest one I have tried and it pegged the needle on my guage. I don't know if the sensor is bad to begin with but I am tired of getting coolant all over the place. I QUIT!!!!!!!!!!!!

 

You do have another option. I had a problem finding a sensor that read right, and I was using the big thread size. Finally I installed a autogauage mech temp gauge and mounted it to the right of the wiper motor. The sending unit on the gauge has small threads and an adapter for the big thread. I installed the sender in the right side head. After that I tried 4 different stock type senders in my orginial hole in the left side head and finally found one that made my dash gauge read correctly. It was a Standard brand part # SDD-TS6. Good Luck.

 

Where do you buy a "Standard brand part # SDD-TS6" sender?

Thanks!

 

Has anyone tried a pipe bushing.That is what
I used on my 76 block when I put it in my 87 camaro.I got it from home depot.

 

I bought the Standard brand sender from Bennett Auto Supply in West Palm Beach, FL. (561-844-8996) ask for Dave. I tried Eckler's, Gm's & off brand and none were correct reading.

 

I wrestled with this last weekend on my stock L-48. With the OEM sensor, the gauge would not come off of 100 degrees. I put a Wells brand sensor in (from Autozone) and the temp shot up tp about 260 degrees in less than two minutes at idle :bs

Bought another brand from another parts store. It works but the temp never jumps above 150 degrees indicated. The car doesn't overheat, so I'm just going to use this as a baseline and mentally compensate :rolleyes:

BTW, remember that there are two types of sensors, one's for idiot lights and the other is for gauges.

 

Thanks for the tip on that sender :cheers:
I just called my regular parts house in California & they have em! :D

 

Let us all know if it works.
How soon will you be trying it ??

 

I'm dropping in the new motor this weekend. I'll probably have it running in 2 - 3 weeks.
I'll keep you updated ;)

 

I have yet to start my engine (although I should this weekend), but here is what I did. I bought a '82 (I think) Borg Warner sensor from Pep Boys with connector. I took it and my stock sensor and measured the resistance in a pot of water on my stove with a candy thermometer. Now, I know what size resistor I need to install in parallel with my new sensor for it to be accurate.

Here were my findings:
Temp----Old Sensor-----New Sensor
155------185ohms-------480ohms
190------134ohms-------275ohms
205------109ohms-------190ohms

So, I need to lower the resistance of my new sensor. This can be done by installing a resistor in parallel (one end connected to sensor wire and the other connected to ground). If the new resistance was smaller, the resistor would need to be connected in series (resister wired inline with the sensor wire).

For parallel resistance, 1/Total ohms= 1/Sensor ohms+ 1/Resitor ohms
In my case, I'm going with a 250 ohm resistor which will make the reading of my new sensor the same as my old sensor at 205 degrees. At 190 degrees, it will be about 3 ohms off and at 155 degrees it will be about 20 ohms off. I think this is definately ok to have with an analog gauge.

 

Paul - I guess I should have read the fine print in your post. I purchased that TS6 sensor only to find it is the same size as the original! :confused: (I didn't see that you typed "big thread size")
The hole for the late or aftermarket heads is much smaller than the original. That is the reason why this thread was started.

While I was at Napa, I did spend some time in their books & found some information I'd like to share with you and everyone else.
According to the Standard catalog, this is what they list for a '71 Corvette:

Temp sensor: TS-6
Thread: 1/2-14
Ohms @100 deg. F: 368
Ohms @220 deg. F: 80

What fits in the aftermarket heads is a smaller sensor for '79 & up chevy, TS-76, but the resistance is all wrong. (see below)

Temp sensor: TS-76
Ohms @ 100 deg. F: 1425
Ohms @ 250 deg. F: 147
(Note how the high side is measured at 250 rather than 220 like the original).

I am going to call Dart now to get this thing figured out.

 

I just called Dart. They told me that they use the 3/8" hole because most buyers are racers & that is what race type aftermarket gauges use. They also said I could drill it out to 1/2" & thread it.
I checked with Autometer Gauges & all of there senders that come with the gauges are 1/8" and are supplied with adapters for the 3/8" hole (late)
& the 1/2" hole (early)
Since I'm not going to pull the head to enlarge the hole,
it looks like I'll be installing an Autometer water temp gauge.

 

OK, just because i was curious, I did some math and I have a (none too positive) result. There is no way to modify the new temp-resistor with adding more (Passive) resistors so it matches the old style. Just plain impossible. I could probably come up with an op-amp circuit that can translate. So if there's no other way, we could make a 'blackbox' that translates the signal of the new resistor to sthg. the old gauge can read. Let me know, if my help is needed.

Stefan

 

Stefan

I agree that you cannot match the older sensor by adding resistor(s) to a newer sensor across the entire range, but it is definately not impossible to make a new sensor practical by adding in a resistor. By adding a 250 ohm resister in parallel with my new sensor, at 190 degrees the new setup will be 3 ohms different than the old sensor. At 205 degrees, it will be the same. For my analog gauges, that is plenty accurate for me.

 

Hell, for all that trouble I will drill and tap the cylinder head first.

I will run it in the intake for a while. If it bugs me, I will drain the system down, drop the exhaust manifold and drill and tap.

 

I know this is an old thread. I was checking to see if there was an update on temp sensors.
Here are findings from another CF member.
Temp(F) Ohms
106 435
137 287
164 180
180 155
190 133
200 115
212 104
Temperature vs. resistance are not linear but exponential. A reasonable compromise is to add resistors so the gauge reads correctly at normal operating temperature.

 

I turn the old sensors down on the lathe, and then re-tread them to 3/8 npt. Works perfect and there is plenty of meat on the old sensor. Take your old one to a machine shop and see if you can get them to do this it will save you all kinds of time and you'll know the sender is correct.

Since the dash gauge is non-linear the old method of adding resistance to the ohms wire will only give you a correct reading at one position on the gauge and the rest will off. If you want to know the calibration scale of your dash gauge unit in terms of what it expects I have this posted on my web site.

Now what you can do is change the resistance to ground on the back of the gauge... but even this takes a whale of time. Making the resistance change on the dash unit will give you an accurate gauge at all temps if trying to match up to a sender.

The issue is you must put a pot in place of the ground and then adjust it until the readings match those of the chart. Once you get the chart working with the proper inputs you measure the resistance on the pot and that is now what you would use for a resistor.

I'm working on one that people can buy, adjust and leave in the car but it won't be finished for a few months.




IMHO,

Willcox