It could be that the two hot cylinders are the ones with the intake leak and they are not getting the cooling from the rich mixture. If you switched the probes and the difference doesn't follow the probe, you probably have a fuel/intake problem of some sort to have that much of a difference in temperatures.
While I was trouble shooting my intake leak, if I run the engine for a few minutes, I couldn't touch the three hot cylinders. But I could rest my hand on the one with the intake leak. It was that much cooler. See below.
There is nothing wrong with my probes. After I fixed the intake leak things are good
On the way to breaking in my engine, my mechanic told me to run it hard for five hours. ECi's break in instructions of course said to throttle back to keep the CHT from getting too hot. Mike Busch emailed me and said to run it at takeoff power for one hour and it would be broke in. He did also say to do whatever you have to do to keep the CHT under 420F.
So for the first 90 minutes of flight I had an intake leak on cylinder #1 which in effect made that cylinder WOT. Didn't matter that I pulled back on the throttle, cylinder #1 had all the air it needed so it was WOT.
After I fixed the problem, cylinder #1 was indeed broke in. It was cooler than the other cylinders. See above. After 30 hours cylinders #3 and 4 have cooled down in line with #1. I'm waiting for #2's temperature to come down. I've been using LOP rather than a rich mixture to keep the CHT cool.
