Leaning Procedure for a Carbureted 182

Howard,

After a couple of minutes the EGT's were
all within 25 degrees of each other.


Just to make something clear about a common misunderstanding he The
goal is NOT to have the EGTs equal. The goal is to have the EGTs in
equal distance from their respective peak. The absolute EGT value
doesn't matter.

--
Thomas Borchert (EDDH)

Juan,

That's not what Continental says about their engine, and not what TBO
Advisor recommends.


Not sure what you mean. What part of the statement you quoted
Continental doesn't say?

--
Thomas Borchert (EDDH)

Frank Stutzman wrote:

3) If I can't get smooth LOP operations with the above, I'll play a bit
with carb heat (which is actually alternate air on my plane). Causing the
induction air to be a few degrees warmer will often help get the
vaporization (and hence good distribution) needed.

How does improving vaporization improve distribution?

One of the things I found with my O-360 and C/S prop is that at
altitudes where the MP falls off, generally to 22" - 23", I pull the
throttle back to see a slight decrease in the MP. Then I lean. I find I
get better fuel burn results and very near the Lycoming manual for this
engine. Leaving the throttle in full at high altitudes, tends to burn
more fuel and I am not sure I am getting anything out of it.

Comments?

Regards, Ross
C-172F 180HP
KSWI


Frank Stutzman wrote:
Doug wrote:


I think the main thing is to lean enough to get proper burn, but don't
lean so much as to burn things up. I have some friends with probes on
all cylinders and carbureted engines who have tried to run lean of peak
and they have mostly given up. Just doesn't work on carbureted engines.


If you said "most" carbed engines, I probably wouldn't quibble. However,
it does work on some. It certainly works on my Continental E-225 with a
Bendix PS-5C carb. Its harder to do, but can be done and does work. Here
is what I had to do:

1) overhauled my carb and had it flow tested to make sure its doing its
job.
2) Pull off the throttle back a bit less than one inch. This put the carb
out of the enrichment mode that it is with full throttle. I think it may
also put a bit of turbulence into the airflow that helps the fuel
vaporization.
3) If I can't get smooth LOP operations with the above, I'll play a bit
with carb heat (which is actually alternate air on my plane). Causing the
induction air to be a few degrees warmer will often help get the
vaporization (and hence good distribution) needed.

I believe I've heard the GAMI folks say that getting good distribution is
easiest on the large Continentals. Something to do with the way
the stock induction is done.

--
Frank Stutzman
Bonanza N494B "Hula Girl"
Hood River, OR

I should mention that I only have a single EGT probe on my engine. I
keep wondering if I should get an analyzer. So much I could buy...

Regards, Ross
C-172F 180HP
KSWI


Ross Richardson wrote:
One of the things I found with my O-360 and C/S prop is that at
altitudes where the MP falls off, generally to 22" - 23", I pull the
throttle back to see a slight decrease in the MP. Then I lean. I find I
get better fuel burn results and very near the Lycoming manual for this
engine. Leaving the throttle in full at high altitudes, tends to burn
more fuel and I am not sure I am getting anything out of it.

Comments?

Regards, Ross
C-172F 180HP
KSWI


Frank Stutzman wrote:

Doug wrote:


I think the main thing is to lean enough to get proper burn, but don't
lean so much as to burn things up. I have some friends with probes on
all cylinders and carbureted engines who have tried to run lean of peak
and they have mostly given up. Just doesn't work on carbureted engines.



If you said "most" carbed engines, I probably wouldn't quibble. However,
it does work on some. It certainly works on my Continental E-225 with
a Bendix PS-5C carb. Its harder to do, but can be done and does
work. Here is what I had to do:

1) overhauled my carb and had it flow tested to make sure its doing
its job.
2) Pull off the throttle back a bit less than one inch. This put the
carb out of the enrichment mode that it is with full throttle. I
think it may also put a bit of turbulence into the airflow that helps
the fuel vaporization.
3) If I can't get smooth LOP operations with the above, I'll play a
bit with carb heat (which is actually alternate air on my plane).
Causing the induction air to be a few degrees warmer will often help
get the vaporization (and hence good distribution) needed.

I believe I've heard the GAMI folks say that getting good distribution is
easiest on the large Continentals. Something to do with the way
the stock induction is done.

-- Frank Stutzman
Bonanza N494B "Hula Girl"
Hood River, OR

"Ross Richardson" wrote in message
...
I should mention that I only have a single EGT probe on my engine. I
keep wondering if I should get an analyzer. So much I could buy...

Regards, Ross
C-172F 180HP
KSWI

More than anything else I have added to the aircraft the cost of
installation and maintence of our Engine Analyzer was many times higher than
the the actual cost of the unit. Seems to be a high maintence item.

Howard

A couple of observations. If you are running rich of peak, you want ALL
they cylinders to be rich of peak and you use the leanest, highest temp
cylinder as your guide. If you are running lean of peak, you want all
the cylinders to be lean of peak, and you use the RICHEST, highest temp
cylinder as your guide. One can see why it is good to have all they
cylinders close to each other. This is what the Gami's do.

As for carb heat. If you put on the carb heat you introduce hot air,
which is less dense. You have just richened the mixture.

As for throttle pull back. If you lean to roughness, then pull back the
throttle, you have just richened the mixture.

There is no magic. You can safely operate at high power setting rich of
peak or lean of peak. To operate lean of peak you need (or want)
EGT/CHT monitoring of all cylinders, fuel injection, Gamis and fuel
flow monitoring to REALLY do it right. You MIGHT be able to operate
lean of peak successfully with a carbureted engine, but most can't
because of uneven air and fuel distribution.

If you operate at about 50% power you can run as lean as you want
because you won't be generating enough heat to do any damage. 65% power
takes 50 degrees rich (or lean), 75% takes 100 degrees rich (or lean),
85% 150 degrees rich (or lean) etc.

"Thomas Borchert" wrote in message
...
Doug,

Running rich of peak
aviods the peak settings that can overheat things and do damage.

Not at all true. In fact, completely false. Sorry.

Come on, Thomas. What in the world makes you think that the effects of heat
due to leaning to peak EGT at high power settings are NOT going to create
problems for the engine? This is common knowledge -- the closer your EGT
gets to 1600 degF for extended periods, the higher the chances your engine
will not reach or exceed TBO. Running at peak EGT at high power settings for
extended periods -will- have a negative effect on your engine. That's why
none of the manufacturers recommend doing this.

It is
false economy to try and run lean AT HIGH POWER SETTINGS and possibly
damage your engine.

lean? How lean? This statement is not true.

No, it isn't. It's manufacturer recommendation.

"Thomas Borchert" wrote in message
...
Juan,

That's not what Continental says about their engine, and not what TBO
Advisor recommends.


Not sure what you mean. What part of the statement you quoted
Continental doesn't say?

Original message:

At power settings above 65% you need to be concerned about running too
lean, thus too hot.

Your reply:

Uhm, no, not at all.

This is wrong. You DO have to be concerned about running too lean, which is
why Continental does not recommend leaning for extended periods of time at
high power settings (above 65%).

"Thomas Borchert" wrote in message
...

Uhm, no, not at all. He'd have to be concerned to run not lean enough,
actually, since the temps decrease again when running leaner and leaner.

....and the effects of increased oxidative attack on the exhaust negates the
so-called advantage of low temps. In addition, TBO advisor adds that "very
little cooling effect is coming from the fuel itself, so CHT does not
respond in quite the same way you'd expect." Running lean of peak also
results in reduced performance, rough engine operation in many cases and
shortened TBO due to the above-mentioned oxidative attack of exhaust and
combustion chamber components. Running lean of peak also has another side
effect, increase in oil acidity, which causes oxidation in engine internal
components (same thing happens if you don't operate the engine often enough
to burn off any condensation in the oil). At lean of peak, exhaust gases
are rich in oxides of nitrogen, which mix with moisture to create nitric
acid, which happens to be extremely corrosive. In addition, TBO Advisor says
there is direct evidence documenting a relationship between ntric acid and
camshaft wear. Because of this, they recommend that if you're going to
operate your engine at best economy mix, lean of peak, then change your oil
every 25 to 50 hours (preferably closer to 25). This method is specifically
not recommended for TSIO-360 series, O-470 and IO-470 series and several
other series and models of engines.