NPT water temp sensor in stock location
 

Some of you may have seen that I am trying to put a 1/8 NPT sensor in the stock 1.6 water temp gauge hole (1/8 BSP). I ordered a glow shift adapter and got this: https://www.miataturbo.net/build-thr...8/#post1211049

Wont work. Someone also recommended this: https://www.miataturbo.net/build-thr...7/#post1208926

But they are out of stock and not expecting anything soon. So it would be special order and $$$$.

I broke this out of my build thread because my google powers have come up dry and need more suggestions.

My final option is to just shove it in there and hope it seals up nice even though the threads are off by one.

My opinion....

If the fittings is steel, and the metal it's screwing into is something softer like aluminum, put some teflon tape on it and screw it in, it will work.

If it screws into something other than say the cylinder head I'd give it a shot.

I'm pretty sure the fitting is brass, and yes, it screws into the cylinder head...

Can you post pics of what you're trying to do? I clicked your link, saw a pic of a brass adapter, that's what you're trying to install? Can you just install the sensor soemwhere else? Installing a 1/8 NPT sensor into say an aluminum housing/water neck/spacer would be super easy, and if you fuck it up, just replace that piece (not the head).

The stock temp sensor is on the back of the head, and I want to replace it with an aftermarket temp sensor, for my water temp gauge. Had I thought ahead I would have tapped my spacer for the sensor but as is I would rather find an adapter so I don't have to deal with pulling the reroute spacer off.

Stock temp sensor:

https://www.miataturbo.net/attachmen...ine=1425438659

What I need to replace it with:

http://www.veisystems.com/ws/sensors...re-sensor.html

Tomorrow I will call VEI and ask about a sensor that has BSP threads. I just need a sensor with the same resistance curve correct?

You are using this sensor for the megasquirt? Should be able to change the thermistor curves if so.

How about these guys? I ordered lots of my turbo fittings here

9042 | BSPT x Female Pipe (NPTF)

Nope, this is for the aux temp gauge.

I'd just pull the reroute spacer and drill/tap and install your sensor. Putting an adapter (spacer) isn't going to make the sensor more accurate, less, as it's further away from the flowing coolant.

Wait stock isnt NPT? Anyways aftermarket brass 1/8 NPT threads right in and seals.

NPT and BSP is so close, it fits nicely.

This is what I'm planning on using in the heater hose.
Coolant Gauge Adapter Small [001-AA-COOLSM] - $35.95 : Advanced Autosports, Miata Race Parts, Spec Miata and TRANS AM Race Car Sales, Service, Build & Rentals Support in Midwest

http://www.lms-efi.com/sunshop/index...t_detail&p=174

In stock.

FWIW, BSP and NPT are close. But if you thread the brass sensor in there and crank it down it will ruin the threads on the sensor or aluminum neck and you'll be lucky if it doesn't leak.

Still not sure if that will work, that one looks just like the one I have. I have been reading more and more about people just threading it in.

Are all temp sensors the same resistance curve? Could I potentially just use a different sensor if it has the same max temp?

Could you boil them, then add resistors in series/parallel to bias the ratio if it doesn't match?

Is there not enough stock to run a drill down the center of that fitting to clear the temperature sensor?

I don't think there is, I need to get a hold of the temp sensor I need to put in. I'm sure I can test them its just a matter of spending more money on finding the right one. I was looking for some background on temp sensors or a way to find stuff.

Well, I know they can work backwards or forwards, meaning they either open up with heat or increase in resistance. I don't think you'd be able to replace one for the other, otherwise the numbers will go backwards.

I'm pretty sure they'll all be designed relatively close, since they are all meant to work in the same temperature range. Any little bit they are off you should be able to fudge with a resistor or two, to get it reading right at operating temperature. That might make it read wrong towards really hot or really cold, but those aren't important.

More encouraging words, so you'll order all the parts and I can just copy you ;)

Thermistor Basics

Ok so I just searched for 1/8 bsp temp sensors and failed....

I think my first test is going to be hook up the oem sensor and see if it reads correctly. I'm pretty sure I threw away the plug though when it ripped out...damn it.

Isn't the plug on the stock temp sender just a 1/4" F spade terminal?

https://www.miataturbo.net/attachmen...ine=1425946110

Is mine not supposed to just be a spade terminal? I guess that's probably more likely.

It probably is. I'm just not at home right now. First test will be plug the gauge into the stock sender and see if the temps match the MS sensor.