What do you guys think is the optimum temperature for our RC engines to opperate at?? It seems like the best place to measure is to point the thermometer down at the glow plug (closest to the head themp). Would the optimum for a 2-stroke be the same as a 4-stroke???

You could develope your own numbers with your own observations of your engines.

Around the glow plug is a pretty good place. It's usually hotter there but the main thing is that you measure at the same place every time.

Enjoy,

Jim

Someone published an article on 4 stroke engines in one of the latest issues of the RC rags( I can't remember which one at the moment) .

In the article, the author measured the exhaust temp with an EGT probe of various popular 4 stroke engines with various configurations and fuels, and the numbers tend to be around 500-550F.

I found it rather interesting that the author compared EGT reading for castor and synthetic on the same engine with same settings and found the engine actually ran slightly cooler with syn fuel.

With fuel tank being 1/8th full start engine and tune high end needle so engine is about 250 rpm shy of max lean rpm at full throttle. Run for full 2-3 minutes and take temp reading.

I have yet to see any specs from any company on the normal operating temps of these glow engines. There are too many variables in the way they are set up on planes and dialed in. My personal opinion is that temp guages are very cute and a waste of money

There is value with a temp guage but that is to measure if your engine is receiving adequate cooling in a tight cowling. Sometimes being 300-400 rpm rich of max lean rpm isn't enough to prevent an engine from overheating. In this instance, anything over 250 deg F is probably not good for your engine with respect to engine longivity.