My Posts: All Forum Topic
I would suggest that where you take the temperature reading from does not matter, within reason. The important thing is to take the reading from the same place each time. We place sensors to our engines, mounted under the cooling fins. The temperature may not be accurate but we are looking for consistency. Over time we can then assess whether the engine is running as we want it. I would however suggest that you don't bother with any readings from the exhaust or manifold, these get very hot and dissipate temperature back to the engine very quickly on landing. Graph below shows engine temp with throttle percentage. Note the engine temp when the throttle is shut down, this is heat from the exhaust going back into the head.
Taking individual readings, requires sound methodology to produce data worth having. Every reading will need to be taken in exact timings to the last. According to our flight recorder, a reading taken just after landing will show an engine with a temperature nearly ten degrees higher than in flight.