Hello,

This is a new machine fitted with a Lycoming O320 (carburetted) and a CS Prop. I've done about 40 hours flying in it and all very good apart from consistently too high CHTs. On take-off (sea level) and early climb CHT's will reach 440 deg F and much higher if I was to steepen the climb to best rate. To keep at or below 440 I need to have IAS of about 120 kts. Fuel flow max is 12.1 gph (46 litres). No amount of experimenting with differing power settings has produced any change. In cruise, at 67% pwr the CHTs will be around 380 deg F with FF at about 8.2 gph (31 litres). Ambient temps don't alter anything much either. HELP! Maybe you know someone experienced with RV problems.

PS The cowls and baffles have been tweaked to provide max airflow already. Thanks.

Not enough fuel flow at takeoff. Unfortunately, Lycoming engines are seldom as easy to adjust as the TCMs, and the parts often have to come off for adjustment. As general rule on normally aspirated engines, divide the takeoff power by 10 to get the desired FF on a takeoff at sea level. (150 HP, should be around 15.0 GPH.)

You sound awfully confident on the baffles!

George Braly spent tens of thousands of dollars doing inflight tests with 36 CHTs, 6 around the circumference of each cylinder, plus dozens of tufts and tiny TV cameras. The results were astounding, very non-intuitive, and not even close to "The Common Knowledge!"

Sounds like a lovely airplane!

Do you have the ring type CHT temp sensors that are placed under the spark plugs, or are the the probe types that fit into the port on the lpcylinder head.
The ring type usually read a higher number than the probe type.

Thanks John and Chuck.