Oil Temp Sensor

[rx7brain]

Would anyone like to recommend a sensor for oil temp logging?
I have a spare 1/8 port, but a doubt there will be one in that size available.

[20B]

Just buy a NPT adapter and use a VDO 10 bar.

[chelspeed]

Putting oil pressure on a tee is fine.

But putting oil temp on an adaptor on a tee is not so good. To measure temp the business end of the sensor needs to protrude into the bulk of the oil flow. If not you won't sense the actual temp you'll sense a temp that gradually soaks into the dead end of oil in the tee. OK for bulk temp over say 10 mins but no good for logging it second by second.

If dry sump then ideally sense the temp in the tank. If wet sump then the temp in the sump, drill and tap the drain plug perhaps?

[rx7brain]

thanks for the advice guys, makes sense what your saying chelspeed.
I'm using a "spacer" that goes under the oil filter to mount the sensors, it has 2 or 3 1/8 ports.
I'll see if there is room to drill and tap out one of the ports.
What size would it have to be?
Can a water temp style be used?
I will look up the VDO 10 bar too?

[RossB]

You can use a normal Bosch water temp sensor for your oil temp (M12x1.5).
I would recommmend a Honeywell 100 PSI pressure sensor (1/8 NPT). These are more expensive than the VDO sensor but are a LOT more acurate and provide much better data. They are also less prone to vibration failures.

[Martin]

What sensor would be suited if the oil temp goes above 120degC?

[RossB]

The Bosch sensor is rated to 130 degrees but will read higher than 130 degrees but the resolution is not so good. Bosch Motorsport have a 150 degree sensor but if you are seeing engine oil temperatures higher than 130 I would suggest that you need to look at improving the oil cooling!

[Martin]

Ive seen as high as 170 with a Bosch 026 sensor, so i cannot trust the value. I must add that values are consistent though. I normally see 140`s, maybe 150`s


Improve the oil cooling? Running fine like this for close to 4 years now, no issues and winning. I must also add that engine temps are higher than normal cars. Another good example of this is the BMW M57TU2D twin turbo 3liter diesel, the thermostat keeps the water temp at light load,idle to about 98,97degC and soars way higher than that when kept in the boost for a while.

[RossB]

Most oils will break down at temps above 130 and the oil's lubrication properties will be reduced. Ususlly the damage to the oil is perminant so the longer the oil is run at high temperature the shorter the useful life of the oil. You could get away with it by changing oil frequently but I would always aim for an oil temp of 100 - 110 degrees.

I assume that it is during races you see these temps?

[Martin]

This is after 3 flyers...100% pace
This car is turbocharged, see intake air temps.

If its in a race it will go even higher. It settles at about 150`s. If the car follows others closely in the race the temps go higher. Never had wear related issues, oil changes not abnormally frequent. Only bearing failures were RPM related after then engine was over revved on downshifts.