Originally Posted by jcarne
If that is true then why does the "data we are yet to see" indicate more sticking valves on the LOP side? Even if an engine is run fairly deeply LOP the EGT's are still notably higher than a typical ROP cruise.
EGT is also an imperfect measure of combustion temperature. It measures the temperature after the gases have expanded and done their work. The temperature early in the power stroke when the cylinder volume is much smaller will be much higher.
If we slow the burning and delay the peak pressure, we will also decrease the temperature. This is why the CHT goes down. It also means that temperature dependent reactions like this will be slower.
So this would seem to be the link to CHT - all else being equal, a higher CHT is an indication of higher combustion temperatures earlier, which will help the lead scavenging reactions.