Here is another set of six exhaust valves, order 1-6.
Interestingly #2 looks like it is running cooler. That cylinder had a severe case of a sticking valve (no compression) and had been repaired by a local UK company. The others are ex US.
OTOH #2 CHT is lower than any of the others. Not surprising since it is in the front of the engine, and while #1 is also, it is having some of its air robbed by the oil cooler intake at the back of the engine. All RH cylinders (1,3,5) are hotter than the LH cylinders.
Another set, cyls 1 2 3 4 5 6 and for each the exhaust and inlet valve.
Pretty much identical to Oct 2022.
The obvious Q is how come the valves look the same year after year, but look so different between cylinders. The differences in CHT are not that great, and differences in the way valves seat in both the cylinder head and the valve guide (these being the primary mechanisms for heat transfer from a valve) could not be so constant from year to year while being so different between cylinders.
Maybe small differences in CHT translate to big differences in valve temperatures? I don’t buy that either; heat flow is basically linear with the temperature gradient. Only radiation is nonlinear but that should not be a big player in those two mechanisms.
@Lucius who started this thread is long gone, having cleared out his profile on the way out
@Peter: for relevant intents and purposes, your exhaust valves are equal: all of them show an axisymmetric pattern. That is what is important. Whether it is a bit darker or lighter or has different circular patterns are details of little relevance if there are no other abnormal symptoms.
Having said that, the old pattern in #2 was a bit more concerning due to lack of symmetry, but whatever it was it has now fixed itself.
Congrats on your excellent valves!
Yes; good point that #2 exhaust has fixed itself. Didn’t notice that!
Another set
Very similar to the previous set.
It’s amazing how different they can look from each other, given that in cruise the EGTs are similar.