I should add that the ECU has a couple different maps or charts that it uses to determine the base ignition timing for a given engine temp, air temp, RPM and throttle position. The map used when the engine is cold is fairly conservative. The only map which is more conservative is the "limp mode" map which pulls a LOT of the advance out, this results in a very weak engine performance wise and can result in a rather hot engine due to the pulled timing. Limp mode is engaged when certain error codes are registered by the ECU (such as code 52: knock sensor error or malfunction).
Your spark advance and mechanical timing also affect the temperatures within the engine. Burn the fuel too soon and you've got a LOT of heat which has to go somewhere and the valves aren't letting it out... Burn the fuel too late and it's still burning when the valves open... cooler engine, HOT exhaust and as such hot O2 sensor and hot hot hot valves.
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