Dynamometer Break-In

[DavidP2020]

Kitplanes Jan/Feb 2024 issue (p.29.) has a sidebar that talks about dynamometer engine break-in.

With the conflict between a nice easy first aircraft flight and pushing the engine for break-in, I can see one advantage to a dyno break-in. A second might be a higher chance of an ideal break-in.

Has anyone done this? If so, what was your experience?

Obviously there is a dollar cost to this. Other pros/cons?

 

[Ironflight]

Factory Lycomings get about an hour and a half “run-in” before shipping, and in my experience, this has oftentimes broken the motor in well enough that it is hard to see a significant CHT drop on the first or second flight. I really like doing first flights on engines that have this factory run time - makes the potential for screwing up the break in process much lower.

 

[DavidP2020]

Factory Lycomings get about an hour and a half “run-in” before shipping, and in my experience, this has oftentimes broken the motor in well enough that it is hard to see a significant CHT drop on the first or second flight. I really like doing first flights on engines that have this factory run time - makes the potential for screwing up the break in process much lower.

Paul,

Are you saying that with a factory Lycoming, with their 1-1/2 hour "run-in", additional dyno "break-in" would be superfluous? That, in this case, doing the break-in on the first (or additional flights, if necessary) flight would be adequate?

 

[RV8JD]

Run-In vs Break-In

Here is some info that may be helpful. A new engine from the factory would have already been run-in, but a newly O/H engine from a shop may not have been.

Run-In vs Break-In:

Ref: https://www.continental.aero/xPublications/xService Bulletins/Experimental PMA/SIL012/

"III. RUN-IN vs. BREAK-IN​

Engine overhaul shops (and new engine manufacturers) typically run-in all engines for a period of one to two hours prior to release for installation in the airframe. However, run-in was never intended to be a complete break-in. The objective of the run-in is to:​

1. Verify the engine meets rated power specification​

2. Correct any oil, fuel, or induction leaks​

3. Check and adjust engine fuel system​

4. Check and adjust engine oil pressure​

After run-in, the engine is released to the installer who provides the airframe, baffling, fuel settings, and all aircraft interface considerations. Break-in is not complete until the engine oil consumption has stabilized and many hours of operation have elapsed."​

​

Mahlon (Russell) has published engine Run-In and Break-In instructions in various places on the 'net, including VAF. Here is one:

http://rvplane.com/pdf/EngineRunin.pdf​

And Mike Busch's presentation on engine Break-In:

https://resources.savvyaviation.com/wp-content/uploads/slides_airventure2021/2021-07-28 0830 F7 Cylinder Break-In Do it Right.pdf​

And article:​

https://www.aopa.org/news-and-media/all-news/2019/january/pilot/savvy-maintenance-breaking-good​

 

[DavidP2020]

Run-In vs Break-In

Here is some info that may be helpful. A new engine from the factory would have already been run-in, but a newly O/H engine from a shop may not have been.

Run-In vs Break-In:

Ref: https://www.continental.aero/xPublications/xService Bulletins/Experimental PMA/SIL012/

"III. RUN-IN vs. BREAK-IN​

Engine overhaul shops (and new engine manufacturers) typically run-in all engines for a period of one to two hours prior to release for installation in the airframe. However, run-in was never intended to be a complete break-in. The objective of the run-in is to:​

1. Verify the engine meets rated power specification​

2. Correct any oil, fuel, or induction leaks​

3. Check and adjust engine fuel system​

4. Check and adjust engine oil pressure​

After run-in, the engine is released to the installer who provides the airframe, baffling, fuel settings, and all aircraft interface considerations. Break-in is not complete until the engine oil consumption has stabilized and many hours of operation have elapsed."​

​

Mahlon (Russell) has published engine Run-In and Break-In instructions in various places on the 'net, including VAF. Here is one:

http://rvplane.com/pdf/EngineRunin.pdf​

And Mike Busch's presentation on engine Break-In:

https://resources.savvyaviation.com/wp-content/uploads/slides_airventure2021/2021-07-28 0830 F7 Cylinder Break-In Do it Right.pdf​

And article:​

https://www.aopa.org/news-and-media/all-news/2019/january/pilot/savvy-maintenance-breaking-good​

Thanks Carl! I've watched Mike Busch's videos, but not seen the Russell article. Very informative.

 

[lr172]

Paul,

Are you saying that with a factory Lycoming, with their 1-1/2 hour "run-in", additional dyno "break-in" would be superfluous? That, in this case, doing the break-in on the first (or additional flights, if necessary) flight would be adequate?

The challenging part of a break in is managing the heat produced from the initial ring seating. This process is mostly done in the first hour or two of high power use. Everything is still breaking in after this period, but the majority of the high heat portion is done (moved on to polishing phase), so less for the pilot to worry about. The time is also dependant upon how the cyl walls were finished. Honing with 220 grit will produce more heat for a longer period. With 400 grit stones, you probably will see only a few minutes of high heat. Problem is, no one is telling use what they are using. Auto engines moved away from 220 grit decades ago, but believe that most of the aviation companies still use it.

Larry

 

[Ironflight]

Paul,

Are you saying that with a factory Lycoming, with their 1-1/2 hour "run-in", additional dyno "break-in" would be superfluous? That, in this case, doing the break-in on the first (or additional flights, if necessary) flight would be adequate?

I certainly wont go out on a limb and say is superfluous - I’d suggest that you talk to Lycoming and see what they suggest. At one time, you could pay them for extra time on the Dyno (since it was already mounted, the “per-hour” cost was, as I recall, considerably cheaper. What I will say is that in my statistically limited experience (a dozen engines?), I have found that with factory steel cylinders, a considerable portion of the break-in occurred during the run-in.

But definitely check with YOUR builder!

 

[DavidP2020]

I certainly wont go out on a limb and say is superfluous - I’d suggest that you talk to Lycoming and see what they suggest. At one time, you could pay them for extra time on the Dyno (since it was already mounted, the “per-hour” cost was, as I recall, considerably cheaper. What I will say is that in my statistically limited experience (a dozen engines?), I have found that with factory steel cylinders, a considerable portion of the break-in occurred during the run-in.

But definitely check with YOUR builder!

Thanks Paul. Personal experience with a dozen engines is a fairly good background! I certainly will talk to Lycoming on the topic of their recommendations and cost/value of additional time on Lycoming's dyno. I appreciate your thoughts!