Cylinder Head Temp Sensors

[chrismorse]

Originally Posted by lightbulb8817

Hoping you got your answer and others can chime in on a separate but related question...

How does the cylinder head temperature correlate to the engine oil temperature?

Reason I ask is because I'd like to program my front-mounted engine oil cooler to turn on when the oil temperature reaches a certain number (>210-220F). However, I would need an temp sensor somewhere in the circuit, which I'm having trouble tapping into cleanly. If the CHT somewhat correlates to engine oil temp, I'm thinking just use that as sensor to trigger oil cooler fan. In other words, does 250F CHT correspond with 210F engine oil temp generally speaking?

The engine oil temp wouldn't help with tuning your motor due to the amount of time it takes for the oil temp get up to adequate levels.

Oil temp does not have a linear relationship to engine temp, primarily because of the thermostat(S) in the system and the oil coolers. CHT would be much better.

I once ran washer shaped sensors under the spark plugs on a turbo 914, but had difficulty securing the washers reliably.

I believe Elephant sells an oil temp probe that is inserted in the fins of the cooler to switch a relay on to the fan.
chris

[David Borden]

Originally Posted by proffighter

Used a Bosch sensor on my SDS EFI like other before

Do you have the Bosch part number for that sensor? It looks as though you are using the end of the sensor to clamp the bracket and wedge the sensor tip onto one of the fins to hold it in place?

[Walt Fricke]

Looks like tightening the sensor clamps it all in place - clever.

[mikedsilva]

Might not be good for the sensor tho?

I'm wondering if there is enough meat in the head, to bore the 10mm hole, and thread it, so the sensor can go straight into the head itself...

[David Borden]

Walt, I agree... Seems very ingenious.

Mike, can you expand on your concern? I see a concern with pressure on the tip if the area below the threads is insulated and not one piece with the threaded area. I would think the direct contact is a good thing if one piece? I suspect the sensor reading would be more accurate with direct contact with the head. I do wonder if that specific sensor pulls the temp from the end/tip or an average of the whole sensor below the hex.

[winders]

Originally Posted by mikedsilva

Might not be good for the sensor tho?

I'm wondering if there is enough meat in the head, to bore the 10mm hole, and thread it, so the sensor can go straight into the head itself...

Agreed...also, the sensor has a lot of airflow around it which would seem to cool it. The Factory head temp sensor is threaded into the head so the part of the sensor that measures the temperature is much less likely to have air flow cooling it.

[Peter M]

Originally Posted by mikedsilva

I'm wondering if there is enough meat in the head, to bore the 10mm hole, and thread it, so the sensor can go straight into the head itself...

Mike,
Yes, good idea. Many bolt knock sensor bridges to the bottom of the heads successfully so there is no reason not to drill and tap for a temp sensor.