Lycoming Break-in Ritual

[David-aviator]

There is a post today about when it may be safe to leave the traffic pattern, the concern being whether or not the engine is OK after 5 hours of boring holes doing the break-in procedure.

As I understand it, the break-in period is running the engine hard to properly seat the rings. If oil blows by the rings before they are seated, the cylinders could glaze with burned oil and the only cure is to disassemble the engine and hone the cylinders to remove the glaze.

My last Lycoming was a 0360-A4M on first run. It was flown about 60 hours on a newly certified aircraft and then overhauled when it hit 2000 hours by Blueprint Aircraft Engines . Blueprint is the company founded by Ed Rachanski Sr., the guy who also caused AvBlend to be certified.

At the time Blueprint had a policy of inviting customers to observe the tear down, which I did. In the process, I asked about the break-in procedure for the new cylinders. They showed me the new Millenium cylinders and said, feel the inside of the cylinder with your finger nails, you can feel the ridges. We hone them before assembly, there is no break-in procedure, just go fly the airplane. And that I did with no problems whatever. The aircraft and engine have since been sold to a friend who flies it very much, also with no problems.

I do not understand why owners of new Lycoming engines, and the clones, have to go through the ritual of seating the rings when it is so easy to not have to do that. What these guys at Blueprint did is very simple and not at all time consuming. I really appreciated it.

David Domeier
Troy, Mo
RV-7A
Currently flying with a Subaru H6
But still in the Lycoming loop

[yakdriver]

When the flying club had a Millenium OH done there is a very specific break in procedure that they want you to follow. The first couple hours were pretty much full throttle then a few more hours at various power settings. Almost every engine rebuilder recomends the high power settings for the first couple of hours. I would follow thier recomendations. Don

[Ironflight]

Check out the web sites for Mattituck and I think ECI - they both have write-ups on break-in procedures, and not only tell you WHAT to do, but WHY you're doing it, along with a good explaination of what is going on, and what you're trying to do.

[David-aviator]

Originally Posted by Ironflight

Check out the web sites for Mattituck and I think ECI - they both have write-ups on break-in procedures, and not only tell you WHAT to do, but WHY you're doing it, along with a good explaination of what is going on, and what you're trying to do.

OK, perhaps I should be a bit more direct in what I was thinking. The notion that it is OK and good to take off first time with a new airplane and a new engine that must be run at very high power for umpteen hours is not good and in this day and age, not necessary. The technology is at least 75 years old, but it does not have to stay that way.

The break-in procedure is with us because the manufacturers do not wish to spend the time or money to build a finished product. Overhaul shops and vendors have no choice but to recommend what they recommend.

When's the last time anyone has had to run at max power to seat rings on an auto, boat, truck, or motor cycle engine. Even my lawn mower engine does not have a break-in procedure.

dd

[vmirv8bldr]

I have no knowledge in this area.

That said, many manufacturers who provide a warranty of any type will require that you do not deviate from their recommended procedures. This would typically include a break-in procedure. Like I said, I don't know if this holds true for aircraft engines, but on a $20k - $30k engine, I'd be willing to humor them for a few hours if it meant keeping the warranty.

My lawn mower did have one. It was to always (ALWAYS, not just to break-in) run on max throttle except for a short cool down just prior to shutoff and a ten-hour oil change. After that first oil change, every 25 hours.

My $0.02