I replaced the ring gear again after breaking some teeth off. I think what happened is at KSNY, I'd forgotten to turn the fuel pump on when starting so rather than a nice rich mixture, there were dribbles of fuel in the cylinders and I may have just bumped the starter switch lightly instead of letting it crank normally and it went crunch.
On the Friday Zoom call, Greg Cross advised that there was a new version of Dynon software released in August. I read through some of the bug fixes, then asked support if I should go ahead and update the software. Seemed like they were pretty responsive initially but it's unusual to go several days without a response. - Update...just got an email stating that corrupt data on a flash may be the cause, so formatted the flashes & updated the software.
The #1 CHT tends to be the coldest. Over the last year, I've made several tweaks to the lower ramps but #1 seems to have the largest delta. Currently #2 is typically the hottest now, sometimes as much as 40F hotter than #1. The 2nd coolest cylinder is still almost as much as 30F hotter than #1. Seems like the last lower baffling/ramp tweak went a bit to far.
I searched on cooling articles in the CSA (now COBA) archives and found ones by Walter Gee and Doug Kouri where they attended a "cooling party". The article is in the April 2014 issue. They used strips glass laid up over a 55 gallon drum, then cut them into 2.5" x 14" strips. Then positioned the forward edge for #3 cylinder (left side) strip 3" aft of the firewall and ends 12 1/8" back. The strip for the right (#2&4) starts at the firewall and ends 10" back. Walter noted that his temps were still higher than the others and his lower cowl leading edge extended into the NACA duct 3" further than the other two planes. He trimmed it back, covered it with duct tape, flew and his temps were down where the other two planes were. I'll take some before/after photos of the cowl ramp changes and add to this post later.
-Update on CHT balancing- 3 & 4 are close and 1 & 2 are close but there's about a 30F delta between the pair so I've trimmed a little off the ramp fences on 3 & 4 to let more cooling air to the aft cylinders.
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