Hi All,

I am having some trouble locating info around which temp sensor I can use on a CA18DET to run the stock 180B temp gauge. Unfortinately I've found the thread for 180B sender will not fit into the CA18.

I've tried to find the resistance details for both the 180B and CA18 senders to see if they match and for the life of me can not find any info.

Can you guys please help out on what sender you used?

Cheers,

I had a quick look in my library and, below and hold, I can't find anything either
However, if you have a working example of both senders you can determine their characteristics fairly easily.
Set up a container with water in it over a hotplate, suspend the sender above the base of the container and connect an ohm meter to the sender terminals.
Like this but using the temperature sender: - Heat the water and observe the resistance readings at various temperatures to produce something like this: - This graph is for the OEM sender as fitted to the FJ20 engine.
You can see that the sender resistance DECREASES and the water temperature INCREASES.
This is known as a Negative Temperature Coefficient device.

Once you have plotted the characteristics for each sender, you will be in a better position to ascertain what the problem is.

I'd be surprised if the senders exhibit major differences in readings, but because they are electrical, it doesn't take much to make the gauge readings meaningless

You may be able to add a trimmer resister to the circuit if the sender values are too low but let's wait and see what your results are first

If you decided to convert to a mechanical temperature gauge, all these problems will go away

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

Thanks so much Nissanman for that post what a wealth of knowledge!
Unfortunately I don't have an example of both senders, nor do I have any idea how to do that test

Totally understand a mechanical gauge would be the easier route to go, but I've tried very hard to keep everything as stock as possible (seems crazy to say that when I have done the conversion ) and would love to keep the stock guages.

Perhaps I can have someone manufacture a thread adapter and use the stock 180b sender, although I can't imagine this is going to be the cheapest option out there.

I'm not the first one to do this conversion surely someone has this info!

I gather the 180B sender is smaller in diameter than the CA18 sender?
If so, we can indeed make up a converter.
All I need is the thread sizes and there might be an off the shelf bush to do it, otherwise a brass plug can be modified to suit.

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

I just did some research and unfortunately I believe the opposite if we go based on thread size.
The 180b sender is M16x1.5 and the CA18 one is M12x1.25.

Based on pictures of the Tridon senders the 180b one is also significantly longer than the CA one.
This has seemed to have gotten more tricky than I expected!

Beaten, we are not yet!
Length, may not be an issue, said the Bishop too the actress!
How about drilling the CA18 sender hole and re-tapping to suit the 180B sender?
I did this to my FJ20 engine so that I could use my already installed mechanical gauge sender.

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

Try an RB25 sender. My Bluebird gauge was innacurate (would read about 90% of scale at normal running temp) with the CA18. But then I built another Bluebird with an RB25 and the gauge read accurately. It's the same thread as the CA18, and Bluebirds are likely to have the same NTC setup as they ran L20Bs in the earlier models.

For the record, the FJ20 sender also reads incorrect in my Bluebird.

Best of luck.

_________________
910 S3 Bluebird - FJ20ET, E85, IRS, 5 Speed, 4.4 LSD
910 S3 TRX - RB25DET, Coilovers, S13 Front end, Power Steering
RA23 Celica - 18RG, Twin 40mm Webers, Coilovers, rolling on SSR mesh 15x7 0s.

Well! there you go!

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

Thank you very much Imago that is awesome!!

I also appreciate your help Nissanman!