Throughout the 2.5 years that the car has been stationary, I have been scouring ebay for some white face Greddy gauges to complement my 1.5 working ones. I had a working boost gauge, and an EGT one with broken sender unit. They have been long discontinued, but I liked the look of them, and I didn't want to spend $200 per on new gauges. So over time, I managed to collect all the gauges and sensors that I wanted. I got all the wiring and a sender for EGT, then got complete water temp, oil temp and oil pressure gauges. So being at the point of my build where I was, I decided it would be good time to look at possible locations for different sensors. I spend couple of weeks reading all of the debates of people saying that it should be here, or here, or you stupid if you are measuring you temperature there. I also spent a lot of time educating myself about the world of pipe threads, more specifically two worlds, American and British.
So for the EGT I had a PT fitting with that came with the sensor. After much research, and also the fact that my probe blew out originally, I looked at the replacement options, for future considerations. The most direct replacement is Defi probe, which cost around $200. Then I also read that people use this replacement probe on Defi gauges.
EGT Probe Exhaust Gas Temperature Sensor - 3/16" Diameter
So I figured that for compatibility purposes I should switch the fitting from PT to NPT one, should I ever have to replace the fitting as well. I got this one, Defi 1/8 NPT Fitting for Exhaust Temperature Sensor PDF01109G at RallySportDirect.com
I have to tap my new stock headers (Tommei headers can go to hell) and I will be good to go.
Next, oil pressure and temperature. Here is where the most arguments were in many threads. A lot of people say to install the pressure sensor in the front galley plug in place of the stock pressure sensor. They say why would you want to keep the stock unit as its useless because it only alerts you when the pressure is really low. And on top of that you will have your more accurate gauge. I went back and forth on that, but I thought that keeping stock sensor is still a good idea, because you don't look on you gauges at all times, but if a dash light comes on you will notice it the same instant. So after much deliberation I ended up installing the Greddy pressure sensor in the rear galley plug. I got the OEM plug with PT threads to match the Greddy/Defi sensors.
With oil temperature, there were also many different ways that I saw people do it. Some people put it in the rear galley plug, some in the front along with pressure one using some adapter similar to this one.
The problem for me was, that if I wanted to use this adapter, I needed all three threads to be BSPT, but all of the adapters that you can find have the side one with NPT. I looked all over the internet to find one with all BSPT threads, and right before completely loosing my mind, I found one on eBay UK. So I ordered it. When I received it, I realize that it really won't work with what I want to use it for. I would probably work for two pressure sensors as they don't protrude past the thread, but it certainly would not fir the temperature sensor, as that one sticks out and the fitting does not have enough room for it. On top of that it does add some height and I don't think it would fit in the front under the alternator, and in the back I wouldn't be able to use it because of what I described. It looks like these fitting adapters were really designed for oil bypass, or coolers anyways instead of multiple sensors. So after wasting couple of weeks getting that adapter from UK, I decided to just keep it simple, STUPID! I ended up getting oil pan drain plug adapter by Killer B, and putting the sensor there
Killer B Motorsport M20x1.5 to 1/8PT Adapter OEMPT at RallySportDirect.com
Water temperature debate was no different. It ranged from radiator hose adapter, to heater pipe, to in radiator fittings (on some Koyo radiators). However, I went a completely less common way. I saw only one person post about it, Patrick Olsen on Nabisco. I tapped the crossover coolant pipe and installed the sensor there. In fact right next to the stock sensor. Because I didn't know how well that would work, I bought another used crossover pipe on eBay for really cheap and decided to experiment with it, so that I would still have my stock one just in case.
This button looking thing looked like a perfect spot to drill and tap as it looked like there was a lot of meat, and almost looked like was there for some possible sensors on other models, I don't know.
I also checked to see if it would not interfere with anything else, and there was indeed a lot of space.
So I got out some smaller drill bits, as well as the final size of 8.4mm one, as specified for 1/8 BSPT tap and started drilling. There was really a lot of metal in that spot so that was good. Then I tapped it with 1/8 BSPT that I got from McMaster, and it was that easy. I used this thread sealant when threadng the sensors in the pipe
And the result was this
I don't know if that is the best way of doing it, and the best place to measure it but that's the way I did it.
The only thing was that because of my piss poor planning I ended up having to take the intake manifold back off.
I had previously purchase the new O rings for the water crossover pipe. When I compared the old ones and the new ones, the old one looked square, or maybe squished from years of sitting in that groove between the two surfaces. The new one was round and was taller, so I am sure it would seal just fine.