Most manufactures have their own marking system for identifying heat ranges of their plugs, but I have some here that I have no idea where they fall, even from looking at the coil.

Is there a way a glow plug could be electronically measured to find its heat range compared to others? I've noticed with colder plugs they use up more amperage to reach the same visual brightness as a hotter plug.

How about using a set amperage and a heat temp gun?

Just putting a plug in and guessing how the motor is working to determine the heat range sometimes isn't the right first step.

G'day Mate,
Check out this web page, it may help a lot.
http://www.scootworks.com/rdrc/gloplugs.html

I think that just about covers my question and more. Thanks!

G'day Mate,
No problem, glad to help.

That is a great site, Alan....[sm=thumbup.gif]

Thank you Mate for the website. Now I have the bible on glow plug use in my engines. It has
been an area that I never realized was so important to overall engine performance. Started
using a Fox Miracle plug in my TT .42 engine during the cold weather with 10% nitro. Once the
weather warmed up, I began have flame outs giving me some dead stick training again.
Once back on the bench, found the engine hot enough to fry and egg. Now I know why. Will
change the plug back to a middle heat range, and try again.

Rich S.