Aztec IO 540 CHT's

[Tired Soul]

Fly an Aztec most of the time.
I keep the CHT's in cruise around 410-430
Recently had somebody tell me that's way too hot, should be 350'ies.
He flies a turbo'd Seneca.
My A&P says it's OK.
Any thoughts?

 

[SlipAway]

From a Textron-Lycoming publication:

Minimum in-flight CHT should be 150 deg F (65 deg C), and maximum in most direct drive normally aspirated Lycoming engines is 500 deg F (260 deg C). Some of our higher powered more complex engines have a maximum limit of 475 deg F(245 deg C). Although these are minimum and maximum limits, the pilot should operate his or her engine at more reasonable temperatures in order to achieve the expected overhaul life of the powerplant. In our many years of building engines, the engines have benefited during continuous operation by keeping CHT below 400 deg F in order to achieve best life and wear of the powerplant. In general, it would be normal during all year operations, in climb and cruise to see head temperatures in the range of 350 deg F to 435 deg F.