Heat is irrelevant 50 below or above. As you lean out the burn is slower this is what is the cause effect on an exhaust valve. Notice that the inlet dosent get damaged at all. The gas flow past the valve going on to extreme lean conditions passes the valve and over heats it. Much like if you get a piece of steel and heat it with a oxy set. Get the metal hot and move the tip around so the heat is not in one place. As you move the tip around the past steel cools. Now place that heat at the edge. What happens it starts to burn the edge. This is the same as what happens to the valve. The colour is very different to a normal valve. Once the valve damaged it will not repair itself. So are burnt valve mine and everyone else imagination. I think not. Also remember that the engine is. at its most stressed on takeoff. Dose the valve burn at this position if it is in good condition no why because the mixture is by manufactures settings is on the rich side of sinc may be they can tell us why that is. Just like they said that the whallya engine was ok cause it was rich enough. It was rich enough until the engine went to full power then it wasn't.
This week I place a plug I placed a plug in the over as I was changing a gear for a starter adaptor. I got the plug hot and I then dropped it into a bucket of room temp water. Gee guess what happen the ceramic cracked.
This myth that if you run lop you will get all your troubles gone is just that. We ran rop we never had a problem in fact we had very little problems at all with our engine. They all made o/h with expect one which had a blower bearing failure that caused that engine to be removed. We done more take off and landings a day than most of you would do in a year. Yet we looked after our engines and airframes.
Now if you won't to run lop do it I'm not telling you what to do. Let's see what tcm have to say I don't know what they have planed. But if you experiment
With lop be prepared to put your hand in your pockets for engine repairs. As I said earlier this is a saving of a few dollars an hour. Expect a bill from $1000 a cly min if you screw it up.
Now they will come back with data distrusting what I have said they have a financial interest in that I have not. I see what I see. Funny they don't acknowledge the work that tcm have put in to provide better reliable engine components. They call there stuff sience we'll what works on paper dosent always work in real life.
They said light was the fastest thing in the known universe then oh we may be wrong the giant collider in France has maybe proven that not to be true. Where dose this leave us now.
Leaves me in the place I started. Leaves you the pilot to decide what you won't to do. People here called me all sorts of stuff yet don't know simple terms parts etc. At the end of the day will it worry me in what you do not really with the exception that if you have an accident I really don't won't to be called into an inquest. If the cly has a damaged valve and until there is documentation to say it's ok ( which I doubt will ever come ) they will be removed and repaired not at my cost but yours.
Cheers