ORIGINAL: proanti1
320 for a few minutes may not be enough to really hurt an engine, but saying temperature doesn't damage an engine at all? That's just stupid. ''Dispersion'' is when aluminum expands when its annealed, and is then rubbed off onto other surfaces. This can happen at 300 degrees. The pistons in RC engines are generally a really hard aluminum-silicon alloy, which resists this wear, but it can still happen. Brass takes on a full anneal at about 450 degrees, but still softens enough to lose its shape long before then... which results in a lost pinch.
320 is too hot for one of these engines. Metal doesn't have to get to its melting point before it deforms.
I wouldn't argue with those scientific facts, but I did accidently run a buggy engine up to 400degF once and no ill effects (that I could tell). I did notice one of my engines detonating once, and the temp was about 320. I like keeping the engine under 300 just because of that. I don't want detonation.
I don't normally liek to quote things that I havn't personally experienced, but I understand that they do run airplane engines around 400degF. I suspect the different fuel lets them get away with that as far as detonation is concerned, but if that is true, I havn't heard about any metal parts becoming deformed.
Any comments from someone who knows more than me about this?