ORIGINAL: BillS
.....friends shoots the temperature at the base of the cylinder and uses 220 F to 250 F as a guide while the engine is running.
Temperature measurement when used with caution could be a good tuning tool but most tend to reject the possibilities and very little data exists.
Bill
I've ask this same question early on and got the same answer, "Don't worry about it".
I'd agree with Bill. In my readings, a properly set engine runs from about 220-250F so I tend to keep it in that range. This does not mean that a perfectly running engine at 260F is a indication of problems though..... and all reading were taken on the bench at about 1/2 (+/-) throttle. I try to keep in mind that the hotter the engine, the more the parts swell.
I've measured both extremes. At 320F the engine was obviously running lean, and I've measured a 180F on my Evo .61NT..... and everything seemed fine, I think it coughed a little in the air though.
I think head temp almost falls under the "Too Much Information" catagory. The temp is relatively useless unless we are talking about extremes. Besides, in the air you can't measure it unless you have a data logger.