Engine Run up & Best Practice

James Hines

Filing Flight Plan
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Aug 21, 2019
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James
In addition to following the POH is there anything else one can do in order to ensure you take a good engine to the sky?

For example, when I do a mag check I look on my engine analyzer to ensure I get a rise in all EGTs when I run on one mag. I also will not taxi the aircraft until I have 90°F oil temp.

Other things I wonder might help. Should I do the run up with the engine leaned out? Should a mag check be a certain length of time like 30 seconds each side? How many times do you cycle the prop?

Anything else I might be missing?
 
I do mag check with leaned out, at times, not every time. Depending on what you are flying there could be tips that people can share. What are you flying ?
 
I have a Bonanza with a IO-520.

If you do your run up leaned out do you notice that the RPM drop is greater/less then say the 100 or so specified?
 
I do a mag check and carb heat check at low rpm, 1200-1500 rpm while I warm the oil. I lean mixture for ground operations and go to full rich for run up before TO. Engine is O-320. Mag check is 10 seconds or so.
 
I also will not taxi the aircraft until I have 90°F oil temp.
In a IO-520-powered Bonanza, while the engine is warming, it does to care if the airframe to which its attached is rolling or not.
Just let off the brakes, and the engine is still warming the oil just as it was when standing still.
 
In a IO-520-powered Bonanza, while the engine is warming, it does to care if the airframe to which its attached is rolling or not.
Just let off the brakes, and the engine is still warming the oil just as it was when standing still.

I'm not sure how this helps me?
 
I also will not taxi the aircraft until I have 90°F oil temp.
I'm not sure how this helps me?
You’re not helping anything by waiting to taxi. In fact if you’re not leaning while sitting, you’re likely just fouling the plugs. Start, make sure you have oil pressure, lean aggressively and do your pretaxi checklist.
 
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You’re not helping anything by waiting to taxi. In fact if you’re not leaning while sitting, you’re likely just fouling the plugs. Start, make sure you have oil pressure, lean aggressively and do your pretaxi checklist.

I believe I am helping by waiting. My airport is hardly level and in order to taxi I often need to go above 1500rpm to get up hills. Without a good temp in the oil I don't like to go that high. First thing I do after start is lean. always have done.
 
My airport is hardly level and in order to taxi I often need to go above 1500rpm to get up hills.
Then I would wait, too.
I used to have a Bonanza with the 520. A couple twists of the throttle and it starts right at 1000 rpm. Being a fairy long taxi to the runway, I would just release the brakes and let the engine continue warming at 1000 rpm while rolling. Oil was always over 100 degrees before run-up.
At that level airport, waiting in front of the hangar, then a long taxi is just excessive and unnecessary ground running.
I wouldn't go to 1500 when cold, either.
 
Then I would wait, too.
I used to have a Bonanza with the 520. A couple twists of the throttle and it starts right at 1000 rpm. Being a fairy long taxi to the runway, I would just release the brakes and let the engine continue warming at 1000 rpm while rolling. Oil was always over 100 degrees before run-up.
At that level airport, waiting in front of the hangar, then a long taxi is just excessive and unnecessary ground running.
I wouldn't go to 1500 when cold, either.
Define “cold”?
As long as the oil is warm enough to be splashing, I think 1500 should be fine. Personally anything above 50° with multi weight oil is probably good enough to taxi.
Start the engine, check for oil pressure, lean the engine, unpack/plugin headset, turn on lights/avionics, get weather all happens before I move an inch. By that time unless it’s close to freezing I should be good to go.
 
In normal weather, what is the benefit of letting the oil warm up to a certain temp before taxi?
 
In normal weather, what is the benefit of letting the oil warm up to a certain temp before taxi?
Personal opinion of SGOTI, none. All the "cold" damage is done in the first few revolutions of the engine. Once oil pressure is up, there's just not a lot of damage being done to the engine from oil below normal operating temperature unless it's seriously cold. If that's the case, you need to pre-heat.
 
I've heard it from quite a few A&Ps and IA that there are many reasons. One is oil viscosity decreases and therefore you can expect lower oil pressure. Another is that the engine (and its metals) expand as they heat. Doing this slowly is better (wear-wise) than not.

Either way, I'm more interested in run up techniques.
 
The lycoming manual for my engine (O-290) says, "Do not operate on a single magneto for too long a period, 2 to 3 seconds is usually sufficient to check drop-off and will minimize plug fouling." I hold it only until it stabilizes, then return to both.
 
It's not just the oil.
Heating and cooling any object causes stresses. The more gradual the temperature change, the less stress.
Idling an air-cooled 520 at 1000 rpm warms the entire engine fairly gradually.
Adding significant power while most of the engine is not far from ambient will rapidly heat the cylinder heads, while the bottom end is still relatively cool.
That's just being a bit harder on the equipment than necessary.
For as expensive as aircraft engines are, why not be as gentle as possible?
 
Looking at my engine monitor data, I see no discernible increase rate the oil temperature rises between 1000 and 1600. Increase RPMs probably provides extra cooling airflow to cancel the extra heat being generated.


Tom
 
The mag check should be quick, nowhere near 30 seconds. You're looking for a drop and continued smooth running operations. That takes a second or two at most. Prolonged operation on 1 mag will just lead to fouling of the plugs that are on the mag that's off.
 
It's not just the oil.
Heating and cooling any object causes stresses. The more gradual the temperature change, the less stress.
Idling an air-cooled 520 at 1000 rpm warms the entire engine fairly gradually.
Adding significant power while most of the engine is not far from ambient will rapidly heat the cylinder heads, while the bottom end is still relatively cool.
That's just being a bit harder on the equipment than necessary.
For as expensive as aircraft engines are, why not be as gentle as possible?

FWIW, I wouldn't call 1500rpm "significant" power.
 
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