Question on CHT during initial climb

A relatively new owner of a 182Q with about 900 hours on its O-470-U18B engine, I have a question regarding engine operation: During cruise I've been religious to keep my CHTs below 380 degrees using a combination of power, cowl flaps, and mixture. What do other owners recommend during taxi, takeoff, and climb? Here in Colorado (field elevation 6200 ft), my local A&P wants me lean the mixture right after startup and prior to taxi. He says it will help prevent fouling the valves. When I finish the procedure, the mixture control almost always looks to be about 1 and 1/2 inch out. And he recommends I leave it there for takeoff. Throttle and prop are max for takeoff. I generally reduce the power and bring the prop to about 2300 about 750-1000 above the ground on the climb. Cowl flaps are open for takeoff and initial climb.

I've noticed the CHTs are above 400 during the climb and I cannot bring them down until cruise. Depending on what altitude I select for cruise, I'm concerned that 10-15 minutes of these temperatures may damage my engine. What advice can members of the forum give me? Should I follow a different procedure or use another technique during climb?

I appreciate any advice.

Comments

  • Scott ShererScott Sherer COO Forum Moderator
    Hi and thanks for writing. I was just in Denver with my twin and experienced that same problem. I generally go full rich if my cylinder temps start to climb, especially during climb. If that doesn't solve the problem and cowl flaps are already open, I'll lower the nose and climb at a shallower angle to keep the airflow up. I just pulled the engine cowlings off to check and see if my engine baffling was okay and it is. That's about all we can do!

    Scott Sherer
    Wright Brothers Master Pilot, FAA Commercial Pilot
    Aviation Director, Cessna Owners Organization Forum Moderator and Cessna Owners Author.

    Need help? Let me know!

  • Scott ShererScott Sherer COO Forum Moderator
    Hi, here's a response from our association A&P, Erich Rempert:

    Ok.

    So you say overheating in climb is an issue, as you must be aware the TCDS states the maximum CHT with a well type CHT probe is 500*F. All your CHT's are under 400* in the picture, I understand the desire to keep the CHT's as close as possible, but 100* difference is generally acceptable especially since you have a carburated engine. The induction will have inherent distribution issues that cannot be overcome.

    I feel I need to suggest that your temps are not outside of what is to be expected for a carburated flat six cylinder GA engine. If you were fuel injected you could get the EGT's and CHT's closer by sizing the fuel injectors, however since you are stuck with a single "one for all" fuel metering point there isn't much you can do besides look for and fix induction leaks at each cylinder.



    That said, I personally don't think your numbers suggest any issues with your engine. If you have more info on climb temps, I'd be happy to give my opinion, but for now it looks like a typical engine.



    ~Erich Rempert, A&P Consultant

    Scott Sherer
    Wright Brothers Master Pilot, FAA Commercial Pilot
    Aviation Director, Cessna Owners Organization Forum Moderator and Cessna Owners Author.

    Need help? Let me know!

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