If you adjust your mixture by leaning to a numerical EGT reading, you
are just asking for an engine failure.
Exhaust Gas Temperature readings are something that few pilots seem to
understand. Unless the EGT sensors were installed at the factory where
they can be calibrated and where each installation is identical you should
ignore the numbers. There are enough variables in our installations that
numerical degree readings are useless, unless each installation is
calibrated often.
There is a a tool for (in the field) calibration of EGT's if you really
want to do this; but most mechanics realize that the system would need to be
re-calibrated often. Many certified EGT gauges do not even have numbers on
them; just an adjustable red line.
If you learn the proper leaning proceedure which includes going to full
rich when decending for a landing; you don't need to have your EGT system
calibrated even once and you never need to care about the numerical EGT
value.
If you are buying an EGT system; look for a EGT gauge with an adjustable
red line and forget about numerical degree values.
After you have your engine jetted properly on the ground; forget about
adjusting mixture until you reach your crusing altitude; then lean to peak
needle reading and set you red line at that position.
I was taught to enrichen the mixture by 50 rpm to be on the safe side
(as too lean a mixture will burn holes in pistons). I understand some
pilots were taught to run 50 rpm on the lean side, but I suspect that
training was for a specific set of engine paramitors (MAP, RPM, Altitude).
----- Original Message -----
From: "Stanley Mello" <myplanewo...@hotmail.com>
To: <kr...@mylist.net>
Sent: Tuesday, January 03, 2006 7:45 PM
Subject: KR> High EGTs
> As was asked, I do have and inflight adjustable mixture conrtrol and an
> Air-Fuel Ratio meter. Everything seemed fine except for the EGT. Also the
> reason for the 6.9 to 1 compression ratio is to allow for the 91 Octane
auto
> fuel here in Calif. The plugs look OK. I was richening the mixture until
the
> engine would start to run rough and missfire and the lean until the
missfire
> would stop, thinking that the mixture would be rich enough to cool the
EGTs.
> Any comments on intake systems?
>
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