Do You Want Your Piston Engine To Last?
Posted: Fri Feb 19, 2016 4:16 pm
It's really pretty simple.
First, realize that the worst enemy of a private
aircraft engine is lack of use. This results in
condensation and corrosion inside the engine.
Lycomings are famous for cam lobe, lifter and
cylinder wall corrosion.
To deal with this, the best way is to frequently
fly the engine, to burn the water out of the
crankcase. You want to see at least 150F on
the oil temp, and after landing, immediately
pop open the oil access door, open the dipstick
or filler tube cover, and make a little convection
chimney, carrying the moisture out the top of
the engine.
Operating Tips
Preheat below +10C. Yes, +10C. Cold starts
are terribly hard on the engine. Don't do that.
There is no oil, and the aluminum contracts
faster than the steel, decreasing the main
bearing clearance to ZERO.
During winter ops, run multigrade. Yes, it's
shit oil compared to straight grade but it's
the choice of the lesser of two evils. See
pour point. You don't want it congealing
in the oil cooler.
Minimum RPM after start to reduce metal on
metal damage and allow oil to circulate. If
the engine occasionally stalls because your
RPM is too low, you are doing it right.
After the first minute or so (depending on
preheat and temps), LEAN THE MIXTURE
and idle at 1100 RPM to reduce spark plug
and valve fouling. Always lean the mixture
on the ground!
No higher than 1100-1200 RPM until CHT 200.
Remember, aluminum piston is heating up
and expanding faster than the steel cylinder,
and it's easy to stuff.
After CHT 200, you can safely runup to 1700
or 1800 RPM and cycle the prop, check the
mags, etc.
For full power for takeoff, it's nice to see the
CHT's climb well into 200F's.
In flight, CHT always above 300F and never
above 400F. Lean the mixture in the climb at
high density altitude with your eye on the CHT.
Lean mixture in cruise. Always.
Lean the mixture in descent and landing. Always.
Lean the mixture on the ground after landing. Always!
CHT is the key to engine longevity. Don't go above
400F in a climb, and don't go below 300F in a descent.
With multi-grade oil, we are not as concerned with
warming the oil after the first start because it flows
very well, cold.
However if your oil temps are abnormally high (250F)
consider changing your oil more often, and looking
at your baffling.
First, realize that the worst enemy of a private
aircraft engine is lack of use. This results in
condensation and corrosion inside the engine.
Lycomings are famous for cam lobe, lifter and
cylinder wall corrosion.
To deal with this, the best way is to frequently
fly the engine, to burn the water out of the
crankcase. You want to see at least 150F on
the oil temp, and after landing, immediately
pop open the oil access door, open the dipstick
or filler tube cover, and make a little convection
chimney, carrying the moisture out the top of
the engine.
Operating Tips
Preheat below +10C. Yes, +10C. Cold starts
are terribly hard on the engine. Don't do that.
There is no oil, and the aluminum contracts
faster than the steel, decreasing the main
bearing clearance to ZERO.
During winter ops, run multigrade. Yes, it's
shit oil compared to straight grade but it's
the choice of the lesser of two evils. See
pour point. You don't want it congealing
in the oil cooler.
Minimum RPM after start to reduce metal on
metal damage and allow oil to circulate. If
the engine occasionally stalls because your
RPM is too low, you are doing it right.
After the first minute or so (depending on
preheat and temps), LEAN THE MIXTURE
and idle at 1100 RPM to reduce spark plug
and valve fouling. Always lean the mixture
on the ground!
No higher than 1100-1200 RPM until CHT 200.
Remember, aluminum piston is heating up
and expanding faster than the steel cylinder,
and it's easy to stuff.
After CHT 200, you can safely runup to 1700
or 1800 RPM and cycle the prop, check the
mags, etc.
For full power for takeoff, it's nice to see the
CHT's climb well into 200F's.
In flight, CHT always above 300F and never
above 400F. Lean the mixture in the climb at
high density altitude with your eye on the CHT.
Lean mixture in cruise. Always.
Lean the mixture in descent and landing. Always.
Lean the mixture on the ground after landing. Always!
CHT is the key to engine longevity. Don't go above
400F in a climb, and don't go below 300F in a descent.
With multi-grade oil, we are not as concerned with
warming the oil after the first start because it flows
very well, cold.
However if your oil temps are abnormally high (250F)
consider changing your oil more often, and looking
at your baffling.