Hi Giff,

Start with something like this:

http://www.harborfreight.com/infrared-thermometer-with-laser-targeting-non-contact-69465.html

Remove the cowl, run the engine on the ground until you get a hot EGT reading on your suspect gauge.  Shut the engine down and leave the suspect gauge powered up.  Shine the infrared thermometer on the exhaust pipe near the suspect EGT sensor.  The suspect gauge and the infrared thermometer should be about the same (at least in the same ballpark).  As the exhaust pipe cools down, the infrared thermometer should continue tracking your suspect gauge reading.

You can also check your CHT calibration the same way.

One thing to note is that infrared thermometers are often calibrated on a flat black object and may read cooler on something shiny like an aluminum cylinder.


Good luck,
Dennis
Legacy 600 hours