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Posted by: shane Oct 13 2019, 08:43 PM

Has anyone with a CHT gauge used a thermometer gun to check the accuracy of it? I was just pointing mine at the base of the spark plug on #3 and was only getting upper 200°. But it may have not been totally warmed up yet and it was just idling.

Posted by: VaccaRabite Oct 15 2019, 08:30 AM

I would trust the CHT (if its a good one) before I trusted the IR gun.

There is not any good way to get the IR gun to measure the head where the ring terminal sits.

Under #3 is the hottest part of the non-exhaust tract for the motor (in theory). So any other place you take a head temp reading (including on the top of the #3 plug) will be cooler - probably significantly cooler.

Zach

Posted by: Mikey914 Oct 15 2019, 10:52 AM

Try to remove it from the car and check by applying some heat carefully with a small torch or lighter.

Just make sure there are no gas fumes.

Posted by: IronHillRestorations Oct 15 2019, 02:34 PM

A non-contact thermometer is a useful tool. Great for checking tires and bearings when towing a load

Posted by: shane Oct 16 2019, 02:14 PM

Great idea, also when you’ve put beers in the fridge recently and checking if there cold enough

Posted by: jd74914 Oct 16 2019, 04:24 PM

Cheap IR thermometers make some assumptions when calculating temperature that you can't change (emissivity and a few other things). It'd be interesting to see what you read if you painted the end or your spark plug vs. shiney metal since that would bring its optical charactertics closer to most of the assumptions.