What temperature should the cylinders be before takeoff

Morgan3820

Morgan3820

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i just finished the install of CGR-30P, so I finally have real engine data. So given a cold start, what temps should the cylinders be before takeoff. I have a oil pan heater, so that helps. Oil temps are not as concerning as I use multi viscosity oil. But what number do I want to see before going full power? I was guessing 120F.
 
I won't apply power until I see 275*. Oil has to be 70* in my Cessna so I use that in the Cub, too.
 
Per TCM there is no temperature requirement. If the engine is running smoothly when you open the the throttle go take off. Why do you assume there is a temp requirement?
 
I know there is no requirement but I makes sense to me that, for engine longevity there is a warm up temp to be reached before applying take off power.
 
My Pilot manual for my TCM or Cont says not over 1000 rpm until oil temp is out of the yellow arc. I certainly wouldn't want to just go full power with cold oil and especially turbo in my TSIO 520 U B. I don't know in numbers where the yellow arc ends.
 
Don't worry about the cylinders. Oil needs to be warm enough though. With my Turbo Bonanzas, it can take as long as 15 minutes before I can takeoff. I don't let the RPM's exceed 1200 RPM until at least in the yellow arc and I won't take off until in the green
 
Add me to the list of those who aren't overly concerned with CHT's. I won't take-off until my oil is over 100*F though. And I won't do my 1700rpm run-up/mag check until it's 90*F. Which works well because by the time I'm done with my run-up and the remainder of the checklist, the oil has made to to take- off temps.

The owner's manual (long before POH's existed) for my plane basically says warm up for an extra 3 minutes and don't worry about it.

But I worry about everything.
 
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Arturo. I think you are only reading part of the instructioins. First it says to pre heat and dilute the oil. Have you ever diutled your oil? Some planes used to have dilution switch where some gasoline was pumped in to thin the oil to be burned off after starting. Don't think your 210 has one. Also says you can use power, IF OIL IS NORMAL READING AND PRESSURE. If oil is really cold it is not going to be normal pressure.
 
On my O-200, the oil hardly ever read a temp on the gauge just sitting there at idle in winter (40 degrees and no preheat). With a good preheat, the oil temp gauge reads well into the green at startup, but quickly drops down as the warm oil circulated through the colder engine parts.

But it always has normal pressure regardless of the temperature. I mean it takes longer to come up to pressure without preheat, but we are only talking 20-30 seconds to stabilize at at normal reading that I would see during all phases of normal flight.
 
Oh, and I have a 150w automotive oil pan silicone heat pad that I keep plugged in when it's cold. I also keep the cowl plugs in and toss a sleeping back over the cowl. The other morning it was 15*F outside when I got to the hangar (probably 5 to 10 degrees warmer inside the hangar). The oil temp was 85 and the CHTs were in the low 60s.

definitely not as good as a tanis or reiff but for $35...hey, I'm a happy camper!
 
My CHTs reach 250° or better within 5 minutes...no way will I be off in less than 5 minutes by the time I get through my checklist
Adjust mixture, power up avionics & ipad, hook up headset, get WX, adjust altimeter, taxi to runup area, etc
Oil temperature rises a little slower, might have to wait a minute if I forget to close cowl flaps because it’s cold.


Tom
 
MooneyDriver78 said:
Oil temperature rises a little slower, might have to wait a minute if I forget to close cowl flaps because it’s cold.


Tom
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OK, that's one question where I've heard both answers.

  1. I've heard that it is fine to leave the cowl flaps closed in cold weather to help get the engine up to temp quicker.
  2. I've also heard to always warm and taxi with the cowl flaps open even in the coldest of weather as localized hot spots can develop if they're left shut.
Anyone know for sure?
 
Bill Jennings said:
OK, that's one question where I've heard both answers.

  1. I've heard that it is fine to leave the cowl flaps closed in cold weather to help get the engine up to temp quicker.
  2. I've also heard to always warm and taxi with the cowl flaps open even in the coldest of weather as localized hot spots can develop if they're left shut.
Anyone know for sure?
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To be clear, at least with my J, even in close position there’s plenty of room for air to escape, they’re not air tight.


Tom
 
MooneyDriver78 said:
To be clear, at least with my J, even in close position there’s plenty of room for air to escape, they’re not air tight.
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OH I get it, I have a J as well, and yes, still room for the air to exit. But, the one who mentioned keeping them open always was a Mooney owner who is also a CFII. I was just wondering if his suggestion has any real basis or if it's BS. I'd think warming with them close would be fine, but...
 
Maybe I am getting senile but I'd bet a grand ok bet $10 that I didn't have any cowl flaps that could be opened and closed by the pilot, on my 1977 M20 J. I just don't have any memory of them or where the control would be in the cockpit? And not sure. maybe 60% sure.
 
Bill Greenwood said:
Arturo. I think you are only reading part of the instructioins. First it says to pre heat and dilute the oil. Have you ever diutled your oil? Some planes used to have dilution switch where some gasoline was pumped in to thin the oil to be burned off after starting. Don't think your 210 has one. Also says you can use power, IF OIL IS NORMAL READING AND PRESSURE. If oil is really cold it is not going to be normal pressure.
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Yes, Bill, my C-210 has an oil dilute switch but is was never hooked up so I used to just pour in gasoline into the oil and then run the engine a minute to mix. This was before multi-viscosity oil. No pre-heat is NOT mandatory per the book, I eventually got a Red Dragon heater but I just heat for maybe 20 minutes which makes starting easier. However, If I can even get my engine started, which means over 5 degrees F, I will fly without any preheat if none is available. I absolutely do NOT believe pre-heat is needed to avoid engine damage. (Do they pre-heat Aspen Volkswagen (AKA Porsche 911) even sub-zero when they bars close?)
 
Snowmass said:
However, If I can even get my engine started, which means over 5 degrees F, I will fly without any preheat if none is available. I absolutely do NOT believe pre-heat is needed to avoid engine damage. (Do they pre-heat Aspen Volkswagen (AKA Porsche 911) even sub-zero when they bars close?)
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I agree if you have flown recently, so there is plenty of oil on the surfaces. But most of our engines use splash oil, as long it’s liquid like, you should be good. So ? Is at what temperature does your oil become have the viscosity of molasses?


Tom
 
Stewartb said:
I won't apply power until I see 275*. Oil has to be 70* in my Cessna so I use that in the Cub, too.
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I believe you will find the oil temperature requirement in the SR22 is 100F. The normal operating range for the Cessna 172 begins at 100F. In the Piper aircraft the normal range starts at 75F.
 
Bill Greenwood said:
you can use power, IF OIL IS NORMAL READING AND PRESSURE. If oil is really cold it is not going to be normal pressure.
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I think you have a turbo which could change things, I am NA and no yellow arc. And if it's really cold. under, say, zero F, I don't think I can get AVGAS to even start. Back in 1979 when it was REALLY cold I needed to start at 5 degrees down in Glenwood and I did not catch the engine first firing and I frosted the plugs so I needed to pull them and warm them. MOGAS, winter grade, will start sub-zero. Pre-heat is nice as it is easier on the battery and, I will use it if I have it, but I do NOT believe there will be engine damage if I do not. Too much is made of the differences between auto and aircraft engines. I asked a Porsche dealer if the aircooled 911 engine, which was also an aircraft engine used in Mooneys, about pre-heat and he looked at me as though I were crazy. There is NO pre-heat requirement on the 911 engine.
 
Snowmass said:
I absolutely do NOT believe pre-heat is needed to avoid engine damage. (Do they pre-heat Aspen Volkswagen (AKA Porsche 911) even sub-zero when they bars close?)
Click to expand...
Not familiar with that engine, but if it's an aircooled engine built by VW it will have thermostatically-controlled cooling air. All VWs did. And it's not being taken to 100% power (and held there) two minutes after startup, either.
 
MooneyDriver78 said:
I agree if you have flown recently, so there is plenty of oil on the surfaces. But most of our engines use splash oil, as long it’s liquid like, you should be good. So ? Is at what temperature does your oil become have the viscosity of molasses?


Tom
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Take a quart of your oil and leave it outside some cold night. Then take a foot or so of half-inch garden hose and try to suck the oil up the hose. If it's hard to move, it's too thick for the engine, which has to suck it up into the oil pumps. THAT is the real problem.
 
We used to look for 200°F before opening the throttle for runup. It doesn't take long to get there even on a cold day. The problems can arise when someone runs the engine hard soon after startup; that aluminum piston is expanding at twice the rate of the steel cylinder, and the piston can heat up faster than the cylinder and close the clearances until it starts scuffing and scoring everything.

Two-stroke ultralight engines are well-known for their tendency to seize if they're not warmed up carefully before takeoff.
 
Dan Thomas said:
Take a quart of your oil and leave it outside some cold night. Then take a foot or so of half-inch garden hose and try to suck the oil up the hose. If it's hard to move, it's too thick for the engine, which has to suck it up into the oil pumps. THAT is the real problem.
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Not in Florida :-)


Tom
 
This 100% power is misleading since the aircraft engine version is simply de-rated to keep the prop RPM down so 100% power might be only 50% of the engines true max power in auto use. Once a myth is accepted people will refuse to question it.
 
Dan Thomas said:
We used to look for 200°F before opening the throttle for runup. It doesn't take long to get there even on a cold day. The problems can arise when someone runs the engine hard soon after startup; that aluminum piston is expanding at twice the rate of the steel cylinder, and the piston can heat up faster than the cylinder and close the clearances until it starts scuffing and scoring everything.
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Then how do you explain the cold WX recommendations by Cessna that I copied in a my previous post which do not agree with you. And why does Porsche not have such a warning? It has aluminum pistons in steel cylinders. And auto engines have aluminum pistons in in massive cast iron blocks which will warm MUCH slower than than the thin aircooled cylinders but cars are often started sub-zero. Myths die hard.
 
Arturo, can we do lunch ? I''ll buy if you let me drive your Porsche. And yes, I do have time in type. I try to drive safely and slowly on the street, but I do miss the race type cars some.
I knew some folks who said one of the trills of Porsche 917 was 217 mph and still accelerating on the straight at Le Mans.
 
Snowmass said:
Then how do you explain the cold WX recommendations by Cessna that I copied in a my previous post which do not agree with you. And why does Porsche not have such a warning? It has aluminum pistons in steel cylinders. And auto engines have aluminum pistons in in massive cast iron blocks which will warm MUCH slower than than the thin aircooled cylinders but cars are often started sub-zero. Myths die hard.
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Not true. That cast-iron auto block is liquid-cooled and the liquid is not circulating until the thermostat opens, or a little will flow if the heater is on. That cast cylinder will warm faster than the aircooled cylinder getting cold air blown over it. Porsche, as I said, will have a thermostatically-controlled airflow so that the cylinders warm up quickly. Never seen any thermostatic air controls on ANY airplane I ever had anything to do with. Manual cowl flaps still allow more than enough flow at idle and lower power settings.

Furthermore, that aircraft engine is loaded as soon as it starts. It's driving that propeller, so the idle is set for more air and fuel than if it had no prop, just a flywheel. No car is loaded like that. And the car seldom gets more than 30% power except for the brief acceleration to highway speeds.

https://www.lycoming.com/sites/default/files/Cold Weather Starting.pdf
 
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So your claiming that thin wall aircraft cylinders will heat more slowly than a massive cast iron block full of water. And it's not even April 1st.
 
Bill Greenwood said:
Arturo, can we do lunch ? I''ll buy if you let me drive your Porsche. And yes, I do have time in type. I try to drive safely and slowly on the street, but I do miss the race type cars some.
I knew some folks who said one of the trills of Porsche 917 was 217 mph and still accelerating on the straight at Le Mans.
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I have never owned a Porsche but you can drive my 60 Caddy in the picture. It is presently at KGWS but will be in Aspen around mid-January.
 
Here is Lycomings cold WX starting advice which says "may cause minor wear below 10 degrees" and "may" is a very weak weasel word. Nothing about actually damaging the engine like piston scuffing.


lycoming preheat.jpg
 
Snowmass said:
So your claiming that thin wall aircraft cylinders will heat more slowly than a massive cast iron block full of water. And it's not even April 1st.
Click to expand...

Here. Argue with Mike Busch instead. He has far more experience than most of us. https://www.avweb.com/ownership/the-jug-jungle/

A quote:

Cold Starts
Cold starts spell disaster for cylinders. A single unpreheated cold start (particularly at temperatures below 20 F) can inflict more cylinder damage than a thousand hours of cruise flight! Contrary to popular belief, cold start damage isn’t caused by lack of lubrication, but rather by loss of piston-to-cylinder clearance. This requires some explanation.
When an engine is cold, there is quite a lot of clearance between the piston and the cylinder walls—usually more than .010″ of clearance. This is necessary because as the engine heats up to operating temperature, the aluminum piston will expand about twice as fast as the steel cylinder barrel will, and the piston-to-cylinder clearance will get a good deal tighter. And that’s okay. But it’s crucial that there always be at least a few thousandths clearance between the piston and the cylinder wall, so that the the oil film is not breached and metal-to-metal contact is avoided.

During a cold start, the piston heats quite quickly, but the cylinder warms up much more slowly because it has vastly greater thermal mass and is covered with cooling fins and bathed in frigid air. Consequently, there is often a period of time—where the piston is up to temperature but the cylinder hasn’t caught up yet—when the piston-to-cylinder clearance can actually go to zero and result in metal-to-metal scuffing of the piston and cylinder walls. That’s why cold starts can be so devastating to cylinders.
 
Bill Jennings said:
OH I get it, I have a J as well, and yes, still room for the air to exit. But, the one who mentioned keeping them open always was a Mooney owner who is also a CFII. I was just wondering if his suggestion has any real basis or if it's BS. I'd think warming with them close would be fine, but...
Click to expand...
Sounds like something made up. Is it in your manual? If not then... How would he know?
 
Dan Thomas said:
Here. Argue with Mike Busch instead. He has far more experience than most of us. https://www.avweb.com/ownership/the-jug-jungle/

A quote:

Cold Starts
Cold starts spell disaster for cylinders. A single unpreheated cold start (particularly at temperatures below 20 F) can inflict more cylinder damage than a thousand hours of cruise flight! Contrary to popular belief, cold start damage isn’t caused by lack of lubrication, but rather by loss of piston-to-cylinder clearance. This requires some explanation.
When an engine is cold, there is quite a lot of clearance between the piston and the cylinder walls—usually more than .010″ of clearance. This is necessary because as the engine heats up to operating temperature, the aluminum piston will expand about twice as fast as the steel cylinder barrel will, and the piston-to-cylinder clearance will get a good deal tighter. And that’s okay. But it’s crucial that there always be at least a few thousandths clearance between the piston and the cylinder wall, so that the the oil film is not breached and metal-to-metal contact is avoided.

During a cold start, the piston heats quite quickly, but the cylinder warms up much more slowly because it has vastly greater thermal mass and is covered with cooling fins and bathed in frigid air. Consequently, there is often a period of time—where the piston is up to temperature but the cylinder hasn’t caught up yet—when the piston-to-cylinder clearance can actually go to zero and result in metal-to-metal scuffing of the piston and cylinder walls. That’s why cold starts can be so devastating to cylinders.
Click to expand...


Yes, Yes, this is exactly what I was talking about. Unfortunately, mike does not offer a 'good to go' temperature
 
Dan Thomas said:
That cast cylinder will warm faster than the aircooled cylinder getting cold air blown over it. Porsche, as I said, will have a thermostatically-controlled airflow so that the cylinders warm up quickly.
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I rebuilt the top end of my 911 - no such thing as "thermostatically controlled airflow". The cylinders are pretty much the same as an airplane. Big ass cooling fan substituting for a prop and baffling to separate the high pressure side for airflow over the cylinders. Think you might be confusing the heat, which is the same as an airplane, so it comes up quick. The cylinders were out in the air. Not sure of % power, but was up to 4,000 rpm while warming up and redline was 6,000+. Same engine was used for some airplanes, but Porsche got worried about liability and exited the market. I'd love to bolt on my old 3.0 liter OHC 6 on to my Archer.
 
Personally I want to see CHTs at 200
 
Dan Thomas said:
Here. Argue with Mike Busch instead. He has far more experience than most of us. https://www.avweb.com/ownership/the-jug-jungle/
Click to expand...
Mike makes his money by writing sensationalist articles for the wide GA audience not for engineers and does a good job at this. At times he has some interesting ideas and at other times he is simply full of BS. Obviously his claims conflict with both the Cessna Manual and Lycoming per the paragraphs I presented and, for that matter, with my own experience.
 
Snowmass said:
Mike makes his money by writing sensationalist articles for the wide GA audience not for engineers and does a good job at this. At times he has some interesting ideas and at other times he is simply full of BS.
Click to expand...
QFT

he preys on right brainers.
 
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