I'm interested in measuring the gearbox oil temperature on my SR20DET gearbox.
I'm currently thinking of using one of the "Engine Watch Dog TM4". http://www.enginewatchdog.com/tm4.html
(I'm not running a MoTeC system nor their system exhaust, so can't use their sensors etc.)
OR just a plain old gauge with a sender and 12V.

Question I have is; where do most people put the temperature sender? I'd prefer to have the sender sitting in the oil to get the most accurate oil temperature, but not sure how to mount something. Is there a way of screwing something in somewhere and it touches the oil? I think drilling a hole may be an option, but getting flakes of aluminium in there isn't.
What does everyone else do?

The "Engine Watch Dog" has a thermistor (or thermocouple) which you screw onto the housing. This is an option, but I still have to find somewhere to screw it onto, and it doesn't measure oil temperature directly, just the aluminium housing.

_________________
1972 Datsun 1600, S14 SR20DET Engineered (204rwkW @ 17psi.)
viewtopic.php?t=6579
#SR20Datsun @SR20Datsun

I have got mine in the filler hole. The filler plug was machined flat and a metric parallel thread tapped. The sensor then seals with an alloy washer.
Might not be the best place to mount it, but there is not many other good spots without welding.
Might look into moving mine in the future when i pull the gearbox again.

The filler plug is also right next to the exhaust on a hot day after about 10 laps at the track the sensor starts giving weird readings. eg max then min scale constantly
Cool it down and it goes back to normal.

_________________
Circuit Race 1600 in the build

Hi Lampy.
Interesting. How do you remove the filler plug now that it has a sensor in it?
Can't you make a stainless steel shroud to minimise exhaust heat getting on it?

_________________
1972 Datsun 1600, S14 SR20DET Engineered (204rwkW @ 17psi.)
viewtopic.php?t=6579
#SR20Datsun @SR20Datsun

The square piece on the filler plug is still there, i just machined the face flat so the washer would seal.

When i want to change the oil i disconnect the bosch "injector" style plug and then use a spanner on the flats of the square section on the filler plug. The sensor comes out with the plug

A shroud is the next plan, if i dont move the sensor to a different position.
I put some of the silicone/glass fiber heat insulation over it but it didnt seemed to help much.
A stainless shield would be the way to go.

Im not sure on the accuracy of the oil temperature measurement in this position
When i first mounted it in the filler plug my reasoning was that the alloy case would conduct most of the heat up to the sensor.
I think a fair bit of oil would be splashing around inside the case as well.
I have gear oil leaking out the shifter hole at high RPM, so there must be a lot splashing around.

_________________
Circuit Race 1600 in the build

If you want a cheap sensor setup you could go with a PT100 RTD and 12v display.
Sensors are really cheap so you could set one up in the diff and one in gearbox and switch between them?

See the ads below

http://www.ebay.com.au.au/itm/Digital-T ... 33931ee94c

http://www.ebay.com.au.au/itm/RTD-Pt100 ... 4d26cedf07

The sensor on that one may be a little long, but there is many others to choose from if you search under pt100 rtd

_________________
Circuit Race 1600 in the build

Cool thanks Lampy. Some good stuff there. I'll have to do some digging on ebay.

There must be a correlation between gearbox case temperature and the oil temperature. I've been told it's about 10 to 20% less of the oil temperature. So technically you could measure the housing temp and hypothetically get the oil temp. Not exactly the best correlation though.

_________________
1972 Datsun 1600, S14 SR20DET Engineered (204rwkW @ 17psi.)
viewtopic.php?t=6579
#SR20Datsun @SR20Datsun