New Carbon Cub

[armaurer]

Just picked up new CC in Yakima and flew it to Florida.
Noted from start that cylinders #3 and #4 run much hotter
than #1 and #2 by about 100 degrees. The rear cylinders
run right around 400 degrees all thirty hours from Yakima
to Florida. Did not lean much as I did not want to let the
cylinders run any hotter. Wondered if other new Carbon Cubs
have had same experience. Trip was over 30 hours as I took
the long way through southern California to avoid Rockies.
Cheers
Alan

[Dan L]

Just picked up new CC in Yakima and flew it to Florida.
Noted from start that cylinders #3 and #4 run much hotter
than #1 and #2 by about 100 degrees. The rear cylinders
run right around 400 degrees all thirty hours from Yakima
to Florida. Did not lean much as I did not want to let the
cylinders run any hotter. Wondered if other new Carbon Cubs
have had same experience. Trip was over 30 hours as I took
the long way through southern California to avoid Rockies.
Cheers
Alan

I see temperature spreads similar to those when I'm running a fairly high percent of power. At lower power settings they all settle in very close to each other. Opening the cowl vents more may help level things out too.

[turbopilot]

Just picked up new CC in Yakima and flew it to Florida.
Noted from start that cylinders #3 and #4 run much hotter
than #1 and #2 by about 100 degrees. The rear cylinders
run right around 400 degrees all thirty hours from Yakima
to Florida. Did not lean much as I did not want to let the
cylinders run any hotter. Wondered if other new Carbon Cubs
have had same experience. Trip was over 30 hours as I took
the long way through southern California to avoid Rockies.
Cheers
Alan

There is a long thread about cooling the Carbon Cub on the forum. You should review it.

Engine cooling has a 1:1 relationship to outside air temperature, so I would doubt you saw a constant 400 dF at the same power and mixture setting all the way from Washington to Florida.

I have done a lot of work to cool and normalize my CHT's. #3 and #4 will almost always be the warmest cylinders in the CC. I have not been able to get all of my CHT's close together but have made pretty good progress.

In my aircraft cruising at POH max continuous power I typically see the warmest cylinder running around the sum of "305" + "OAT in dF". So if the OAT is 80 my warmest CHT will be around 385 dF.

Here is a screen shot of my CC from a few days ago. This picture was taken after running 2 hours at the same "max POH power setting".