Very cold weather engine break in?

We are just about ready to start up our new Thunderbolt 540 on out RV-10. Thinking we will start later tomorrow or maybe Sunday.. but might not fly this weekend.

Today?s high was 2F. This weekend isn?t going to be so terrible, but I?m still just wondering if there is anything I should do different for break in with it this cold out. I know to avoid shock cooling. I plan to descend by gentle power reductions to try to keep CHTs from dropping more than 50F per min.

I plan to run it had, as per the Lycoming instruction and keeping CHT as low as possible. But if CHT stays low, say under 400, can I run it too hard? 5000? msl right now might be 3000?DA here over next week.

Should I postpone flying in the extreme cold or use the cold to run the engine hard?

Next week the forecasts are showing highs still well below 0F.

First off, shock cooling is a myth. If that weren't the case, no twin engine training aircraft would make it to TBO. Most exceed it.

Secondly, just make a few ground runs and shut down upon reaching 300 CHT. Let the engine cool completely before running again. Done. Go fly.

rocketbob said:

First off, shock cooling is a myth. If that weren't the case, no twin engine training aircraft would make it to TBO. Most exceed it.

Secondly, just make a few ground runs and shut down upon reaching 300 CHT. Let the engine cool completely before running again. Done. Go fly.

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That’s what I figured. Just trying to be sure I do it right. My family will be in this plane a lot.

The ramp is snowy. Suggestions on how to secure the plane? I’m okay using my car (it’s a beater) tow hitch.

Chock it and thats it. A couple of runs at fast idle.

as long as you keep the CHT's in line, you can't run it too hard during ring seating. The cool temps are your friend here as it will help to keep the CHTs lower. Just avoid starting the engine when it is cold (as in below 40 or so).

Larry

rocketbob said:

First off, shock cooling is a myth. If that weren't the case, no twin engine training aircraft would make it to TBO. Most exceed it.

Secondly, just make a few ground runs and shut down upon reaching 300 CHT. Let the engine cool completely before running again. Done. Go fly.

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Yeah, I'll tell that to the guy that tried beating the jumpers down in his C-206 in and broke his engine. What does being a twin have to do with it? I doubt one engine out conditions last for extended periods during training.

Look at all the Extra 300's and airshow guys. Full on power with almost no air flow when doing a torque roll or other vertical up /hanging on the prop display items, to nose down and 200 kts. They get brutal hot to cold and back to hot cycles. Some of them make it well over 1400 hours.



To the OP, my only concern would be to try and keep the oil temp above 170 and preferably 180 -190. Hopefully you have a cockpitt adjustable butterfly valve in the air duct to the oil cooler.

F1R said:

To the OP, my only concern would be to try and keep the oil temp above 170 and preferably 180 -190. Hopefully you have a cockpitt adjustable butterfly valve in the air duct to the oil cooler.

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This point is a real concern for cold-weather break-in. We broke in our O-360 in December '17 and delayed the first flight until the temperature warmed UP to -15C. CHT's weren't a problem, and we were able to run the engine hard without concern. The butterfly valve on the oil cooler feed allowed oil temps to stay between 175 and 180.

Preheat the dickens out of the engine before you light it up so you don't spend forever idling on the ground. For our first flight the pre-heaters (Reiff Turbo XP) had the engine up well into the yellow arc before turning the key. By the time the runup was complete oil was in the green, so ground delay for warm-up was nil.

Plus, if you're doing your first flight in this cold weather, hang onto your hat as the performance will be OUTSTANDING!

Tommy123 said:

Yeah, I'll tell that to the guy that tried beating the jumpers down in his C-206 in and broke his engine. What does being a twin have to do with it? I doubt one engine out conditions last for extended periods during training.

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I agree, I suggest you tell him shock cooling is a myth and driving a windmilling propeller at high speed causes other failure modes.

Canadian_JOY said:

This point is a real concern for cold-weather break-in. We broke in our O-360 in December '17 and delayed the first flight until the temperature warmed UP to -15C. CHT's weren't a problem, and we were able to run the engine hard without concern. The butterfly valve on the oil cooler feed allowed oil temps to stay between 175 and 180.

Preheat the dickens out of the engine before you light it up so you don't spend forever idling on the ground. For our first flight the pre-heaters (Reiff Turbo XP) had the engine up well into the yellow arc before turning the key. By the time the runup was complete oil was in the green, so ground delay for warm-up was nil.

Plus, if you're doing your first flight in this cold weather, hang onto your hat as the performance will be OUTSTANDING!

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+1 I did my FF last year Jan 17, not too far south of you. You also might get some roughness hesitation until the servo is off the idle circuit. I had to ranches mine considerably for that.

You have a 10 so cabin heat might not be a issue, but expect very cool EGT's , maybe as low as 900F. That is normal. I would not lean or not much, maybe up to 1100 F EGT. But not on the first two flights.

I started with the oil cooler fully closed. It vibrated open and OT still was good.

Happy Safe first flight!!

Today could be your only window for a week.

I added a TCW butterfly last winter, without we were gettingoil temps at most of 145. Now that we have it I can get 200 easily when it is 5F out.

We will see how it goes when it is -5F to -10F.

Thanks!

Well, at 0F it ended up running just fine. But, without the cowling on the oil temp went from 75F startup, to 78F after 5 mins running. Had it on the pan heater for 24 hours prior, and dropped 20 degrees in the 10 minutes it took before I could get it started.

Everything seemed fine but I decided to not run higher than 1500RPM with the oil temp that low. I figure adding the cowling will help. I stopped when the first CHT hit 300F.

I'm thinking I'll run it again tomorrow for further leak checking, then cowl it and plan to fly it Thursday morning.

From the Superior engine overhaul manual, break-in section:

?Caution: break-in of an engine in frigid conditions can lead to cylinder glazing and failed break-in due to low oil temprature. It is recommended that oil temprature be maintained between 180 and 190 degrees F?

I personally don?t yet understand why that would be the case.