What temperature should the cylinders be before takeoff

I warm up my O-320 until the oil temp is in the yellow arc. RPM at or below 1200 rpm. My oil pan heater helps a lot during winter operations. After a 5 minute warm up CHT's are always above 200F. Oil pressure is about 90psi. Oil pressure at cruise is normally 80 psi. CHT's are in the low 300's.
 
AKBill said:
I warm up my O-320 until the oil temp is in the yellow arc. RPM at or below 1200 rpm. My oil pan heater helps a lot during winter operations. After a 5 minute warm up CHT's are always above 200F. Oil pressure is about 90psi. Oil pressure at cruise is normally 80 psi. CHT's are in the low 300's.
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Thank you. From a person with cold weather operations, that was helpful.
 
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. Obviously his claims conflict with both the Cessna Manual and Lycoming per the paragraphs I presented and, for that matter, with my own experience.
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I like Mike Busch. I think that he offers a lot of insight along with the data to support his position. As for oem manuals, I work as an engineer for a dod overhaul facility and I have found oem manuals to sometimes be in error. Useful consensus, seems like cht of 200F is a good number. Allowing a warmup in cold weather to me makes sense. No warnings of engine harm from a warmup have been offered.
Thanks to everyone for their input.
 
All y'all need to see the inside of a cylinder and top of a piston after a few cold starts. There is metal-to-metal contact if it isn't done right......
 
Stewartb said:
So none of you motorheads who lives in a cold climate has ever cold seized an engine by being impatient and applying power without warming it up? Cold weather advice by warm weather guys is funny to read.
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If by "cold seizure" you mean growing the piston more quickly than the cylinder can warm, causing an interference fit, I've seen that in two-stroke motorcycles that had the minimal piston/cylinder clearance. If you mean "cold seizure" by lack of oil film due to high viscosity, nope, never seen that in anything. 'Cuz I warm stuff up.
 
I have never "cold seized" and engine nor been able to start on AVGAS below zero but I did start my pickup at Crested Butte CO at -17 degrees F but it took a tow start to do it. The starter wouldn't handle it. No engine damage.

My flights are southern Arizona highlands to Colorado Rockies mostly in winter. BTW on December 9, 1978 a Phoenix newspaper headline screamed, "52 BELOW ZERO AT HAWLEY LAKE (Arizona)". Cold enough for ya?
 
I've started engines in -50F more times than I'd like. Try riding a snowmachine in a 40mph headwind at -52. No beer stops in those temps. My wife draws the line at -30 for the 30 mile ride to the cabin. My airplane record (if memory serves) was -42 but we didn't take off until the heat of the day.... -38. Good times. NOT!
 
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Let's get real for a moment. What dictates my desire to take off is usually my ability to take off. In cold temps when I get into my planes my body and breath ice the inside of the windows instantly. I have to warm the plane until the defroster clears the windscreen. That requires more than slow idling to heat the muffler and to move air through the heat system. By the time I can see the engine is ready to go, for sure.
 
I look for 200 degrees CHT before takeoff, oil temp may be near 90. This is usually over 5 minutes since startup, preheat when required.
 
Snowmass said:
I have never "cold seized" and engine nor been able to start on AVGAS below zero but I did start my pickup at Crested Butte CO at -17 degrees F but it took a tow start to do it. The starter wouldn't handle it. No engine damage.

My flights are southern Arizona highlands to Colorado Rockies mostly in winter. BTW on December 9, 1978 a Phoenix newspaper headline screamed, "52 BELOW ZERO AT HAWLEY LAKE (Arizona)". Cold enough for ya?
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On the Canadian prairies we regularly go places at -40°C (same as -40°F). I often got the truck started at those temps without it being plugged in, until one morning the bearings began to rattle and I noticed there was no oil pressure. I had 15W40 in it and it was too thick to pump. The local bulk plant guy told me that lots of the farmers used 0W30 in the winter, and often year-round if they weren't towing anything. I switched to that and had no more trouble. In my current truck I use 5W30 year-round and plug it in if it's going to get nasty cold.

Some mornings we could have that -40 with a wind chill of -50°C or worse. That's -58°F. One needs to put a jacket on. Maybe a hat.
 
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Busch says:

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!

I've seen variations of his "cold start" claim for just about everything that has an engine, but one thing that's always absent is some sort of reference that backs up the assertion.

A Google search of the phrasing brings up the exact verbiage, without attribution, in documents more than 30 years old. That makes it obvious that Busch, like dozens of others, simply copied the words. He presents them as fact, when there is no basis for the claim that I could find.

Of course, there's no denying that cold starts cause greater wear on an engine than a summertime start in Florida. I'm just troubled that so-called airplane expert Busch copies a decades old statement word for word, presents it as his own findings, and infers some sort of research produced the screed.
 
The logic is this:
Aluminum expands almost twice the rate of steel as it heats up. Under cold conditions, the aluminum piston heats up before the steel cylinders because the cylinders (and heads) are being cooled being exposed to low temperatures. This is further exacerbated by the cold thick oil not being splashed on the pistons and cylinder walls.
So the pistons over expand, no oil on the walls, then end up scraping the walls under pressure.
This should be easy to test. Borescope an engine, start it under cold conditions, borescope again...look for scraping marks on the walls.


Tom
 
MooneyDriver78 said:
The logic is this:
Aluminum expands almost twice the rate of steel as it heats up. Under cold conditions, the aluminum piston heats up before the steel cylinders because the cylinders (and heads) are being cooled being exposed to low temperatures. This is further exacerbated by the cold thick oil not being splashed on the pistons and cylinder walls.
So the pistons over expand, no oil on the walls, then end up scraping the walls under pressure.
This should be easy to test. Borescope an engine, start it under cold conditions, borescope again...look for scraping marks on the walls.


Tom
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the damage is around the top of the piston and at the top of the cylinder stroke.....lots of scuffing in those areas.
 
You should let the cylinders cool to room temperature before you take them off, otherwise, you'll burn your fingers.
 
3393RP said:
Busch says:

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!

Of course, there's no denying that cold starts cause greater wear on an engine than a summertime start in Florida.
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Thank you for your intelligent post. According do Busch then two starts at 19 degrees or lower would have exceeded the TBO for my IO-520. Looks like my engine has already gone way beyond 10,000 hours. If TCM only knew.

But, as usual, I am not going to believe anything (I was not popular in church) without reasonable proof. And I fail to see why a cold start must produce more wear. Cold oil is thicker and, therefore, has a higher film strength and even more protective. BTW, most today believe that oil pressure to bearings is required to prevent disaster. The very reliable Chevy 6 had NO OIL PRESSURE to the rod bearings into the 1940s.
 
Snowmass said:
Thank you for your intelligent post. According do Busch then two starts at 19 degrees or lower would have exceeded the TBO for my IO-520. Looks like my engine has already gone way beyond 10,000 hours. If TCM only knew.

But, as usual, I am not going to believe anything (I was not popular in church) without reasonable proof. And I fail to see why a cold start must produce more wear. Cold oil is thicker and, therefore, has a higher film strength and even more protective. BTW, most today believe that oil pressure to bearings is required to prevent disaster. The very reliable Chevy 6 had NO OIL PRESSURE to the rod bearings into the 1940s.
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Thick oil doesn't get to where it needs to be fast enough. And thick oil isn't better, necessarily. Cars often use 5w20 year-round.
We've talked about the "splash" lube before. Those old engines had scoops on the rod caps that forced oil under considerable pressure into the bearings. It was discontinued because oil level was too critical. And slopes sometimes starved the bearings.

Cold starts anywhere in AZ. Riiight. Let's try MT or AK shall we?
 
Snowmass said:
Thank you for your intelligent post. According do Busch then two starts at 19 degrees or lower would have exceeded the TBO for my IO-520. Looks like my engine has already gone way beyond 10,000 hours. If TCM only knew.

But, as usual, I am not going to believe anything (I was not popular in church) without reasonable proof. And I fail to see why a cold start must produce more wear. Cold oil is thicker and, therefore, has a higher film strength and even more protective. BTW, most today believe that oil pressure to bearings is required to prevent disaster. The very reliable Chevy 6 had NO OIL PRESSURE to the rod bearings into the 1940s.
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Then start your 20F engine at 1800 RPM. You have not produced any reasonable proof that it is bad to warm up a cold aircraft engine. Simply repeating, "I wouldn't do it', doesn't offer much reasonable proof either.
 
Dan Thomas said:
Thick oil doesn't get to where it needs to be fast enough. And thick oil isn't better, necessarily. Cars often use 5w20 year-round.
We've talked about the "splash" lube before. Those old engines had scoops on the rod caps that forced oil under considerable pressure into the bearings. It was discontinued because oil level was too critical. And slopes sometimes starved the bearings.

Cold starts anywhere in AZ. Riiight. Let's try MT or AK shall we?
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My cold starts are in the Colorado Rockies where I ski regularly but FYI Arizona has been colder than Anchorage AK. Check it out.

However, I have repeatedly said not below zero since my engine won't start.
 
My thoughts on this -

If you place a substantial heat source on the inside of a thick-walled cylinder, there will be a transient distortion which the cylinder goes out-of-round and in which the cylinder wall comes in. I proved this many years ago on a servo hydraulic cylinder using a bore gage, after having a number of them score in the field. If finite element analysis is done to this setup, this is theoretically obvious. In other words, a hot spot in a cylinder will cause the cylinder to go temporarily egg-shaped but not expand, rather it contracts. I called this thermal instability. In each case the scoring was similar on directly opposite sides of the cylinder. Except that once during these tests I saw a scoring in three locations separated by 120 degrees, at which point I realized that the scoring was caused by a opposing force and not just a side load.

This is especially critical on a reciprocating piston sliding in a cylinder with marginal or no lubrication. The cylinder can clamp down on the piston, and the piston will expand to more-than-meet the cylinders hot spot. There is a lot of concentrated power available from the engine to create such a temporary hot spot.

Most cases of engine cylinder scoring involve simultaneous scoring on opposite sides. Why is this? If the pistons could rotate (obviously an engine doesn't work that way!) and not just reciprocate, scoring wouldn't happen as even temporary heat would be distributed around the cylinder. I contend that this is not just a lack of lubrication, but also caused by some form of similar thermal instability, in which a cylinder goes temporarily out of round in response to marginal lubrication and a hot spot, and simple normal expansion rules don't apply.

In engines I have also seen where the scoring will be worse on the right hand side cylinders, but that only makes sense because the top RH side of an opposed engine will be more marginally lubricated by splatters from a CW rotating crank and will more likely starve this area.
 
Good post, Mr Petersen. Thanks!

I live where it’s cold and for 25 years parked airplanes outside. Here’s my quick summary of preheat and why. Say what you want about cold starts but the one single factor that makes successful starts is rotation speed of the starter. Bad mixture and weak spark is minimized by fast rotation. The best way to assure that is to preheat the oil adequately. The problem with that is in cold weather (not Arizona cold ;) ) the air cooled cylinders are still cold and with moisture released from oil? You can still frost the plugs. If you choose warm air heat, like a Red Dragon, and you use it impatiently for just a few minutes like most guys, the air warms the cylinders quickly and allows them to fire up. In cold weather the oil is a gooey glob and you sit there idling and oil pressure remains on zero for way too long. The solution is to preheat oil and cylinders adequately to promote fast spinning, easy firing, and quick oil flow. I have a brand new Lycoming sitting on my hangar floor ready for the Cub. The motor less fancy accessories cost $40K. Given the investment and the amount of trust I place in that engine to run well I’ll preheat it as best I can. Regardless of the silly fictional analogies I read on the internet!

Merry Christmas, guys and girls.
 
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Morgan3820 said:
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.
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How are oil temps not a concern because you are using multi-viscosity? Multi-viscosity makes starting easier at lower temps, but I’ve never seen any documentation that changes the redlines on your temp gauge due to the oil. Regardless of what weight or multi-weight you use, you still need the oil temp to be above whatever the min redline/yellow line is.
 
Morgan3820 said:
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.
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Haven't flown it with the CGR yet? I'll bet the are passed 120F maybe over 200F by the time you are ready for takeoff.

Then again, I taxi, call clearance, ground, tower, runup, checklist and all that.
 
bnt83 said:
Haven't flown it with the CGR yet? I'll bet the are passed 120F maybe over 200F by the time you are ready for takeoff.

Then again, I taxi, call clearance, ground, tower, runup, checklist and all that.
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Flown only once post install, prior to neck surgery. I was worried more about oil pressure at the time as we put in a new pressure regulator and weather was warm. Later, the lows went down in the 20’s when the plane partner flew to Florida for Christmas. Which got me thinking about the original question. But you are probably correct as I fly out of a class D with at least 5 minute taxi time. I was looking for a number, which consensus seems to be 200F
 
Stewartb said:
the air cooled cylinders are still cold and with moisture released from oil? You can still frost the plugs.
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The moisture that frosts the plugs (and inside the head and on the piston crown) comes from the first couple of combustions. If the engine doesn't catch and stay running, that moisture makes sure everything stays dead.

Apply the flame from a propane torch to a cold metal surface and see the moisture form instantly. Byproduct of combustion.
 
Snowmass said:
My cold starts are in the Colorado Rockies where I ski regularly but FYI Arizona has been colder than Anchorage AK. Check it out.

However, I have repeatedly said not below zero since my engine won't start.
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Zero F is only -18°C. We used to start down to -25°C. There are Alaskans (and some of us Canucks) that start much colder than that. Anchorage is a coastal city and the ocean moderates the temperature.

Those cold-weather people are tough. They tell stories of the cold, like not being able to talk outside because your words freeze and fall to the ground and the other guy can't hear you. In the spring all that verbiage thaws out all at once and makes an awful racket. In the cabin you have to keep the stove stoked right up or the smoke will freeze inside the chimney and then back up into the house and choke everybody. You gotta go up and take a long stick and punch the frozen smoke out of the stovepipe. ;-)

I've seen diesel fuel freeze in a transport truck's tanks. Guy came to the interior of BC and had last fuelled up in Seattle. From Texas, he was. I asked him if his antifreeze was good for -40°; he just laughed. "Can't possibly get that cold," he said. That night the antifreeze froze and the diesel gelled. Coastal warm-weather fuel, see? Not the stuff for cold weather. Too much paraffin in it. Got down to below -30°C. He had to have the truck towed up to a truck shop and it sat for two days inside to thaw everything out. "Never coming back here again!" he said. He was wearing those polyester dress pants that were so fashionable in the 1980s. That cold wind just cruises right through them as if you had nothing on at all.
 
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