Starduster Too HO-360 break in CHT issue

[harleygaz]

Hi. I have an overhauled to zero TSMO HO-360 in my Starduster that is giving very different CHT readings on the cylinders. The Lycoming manual gives 65% power and 70% power both at 2700 RPM but I think that's for helicopters so I'm using 2600 and 2700. The engine had an hour on a test stand, maybe 30 minutes ground runs to cecl installation and 3 hours air time. In the climb at full rich and WOT I'm getting over 500 on #3 cylinder and in the cruise at 2700 it won't come below 500. at 2600 it'll come down to maybe 490 and at 2500 470-480. #1 and #4 never exceed about 480 at 2700 and fall to 460 at 2600, #2 never exceeds 400 at all. I've been keeping the RPM down to avoid overheating but I'm afarid that will prevent proper brak in. The 3 flight so far indicate about 1/2 quart of oil per hour and a cold compression checl gave all 4 cyliinders 78 to 79 / 80. Plugs show a very rich mixture. Tomorrow I'll try swapping #1 and #3 CHT propbe (bayonet type) in case it's the probe. Cowling is the standard open front Starduster nose bowl and baffling and seals look OK. I don't want to ruin my new engine by over heating but I do want to break it in properly so I would appreciate any help in where to look next. I posted the same thread to the firewall forward lycoming forum but thought maybe there might be a known SD2 colling issue on #3 cylinder.

 

[Melndav]

 

[harleygaz]

 

[PittsDriver68]

 

[biplanebob]