Unfortunately, for a carb'd O-540 like that, having an EGT gauge isn't too
terribly useful for leaning in cruise. It *is* useful for progressive leaning during
a long climb. That is, note the full-rich, sea-level, max-power takeoff EGT and lean
during the climb to hold that (e.g. 1300).

For cruise, however, you'd be better off ensuring running at 70% or less, and
leaning as much as possible, all the while ensuring that CHT never goes above 375.
If it does, enrichen so it doesn't. If over 75%, enrichen to that same "full-rich"
EGT (e.g. 1300). Likely the O-540 will run with a few cylinders lean of peak, a few
at peak, and a few richer than peak when leaned fully to roughness. That's as good as
you can do... just keep the power at 70% or lower.

flame suit activated
-Cory

Dean wrote:
: On my first flight in the Aztec with a fellow pilot who was doing the
: flying, he stated to lean using the EGT (a recently installed
: Electronics International digital single probe device)to circa 1300 and
: no higher than 1350.

: The aircraft does not have a CHT.

: I am totally new to operating larger engines like the O-540 (no fuel
: injection here) and want to ensure I dont damage anything. I hear a lot
: of talk and hearsay about LOP/ROP leaning procedures.

: Like most owners, I want to operate my aircraft efficiently, but not to
: the detriment of engine reliability.

: Any advice is welcome.

: Regards,

: Dean


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************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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