Hello fellow Comanche owners,
My engine has been overhauled by Central Cylinder Services (CCS) in Omaha. I had them install original Lycoming cylinders. In anticipation of having to break in the freshly overhailed engine, I've read quite a few articles on the break-in process, including Lycoming SI 1014M ()

CCS gave very simple break-in instructions such as not to use detergent oils, first running the engine for a few minutes, letting it cool, checking for leaks, and repeating the process 3-4 times, frequently changing power settings between 100% and 75%, etc.

The mechanic, installing the engine, was recommending that I use Phillips X/C oil from the start. However, Phillips X/C is an ashless oil with dispersant additives. Nearly every article I've read (as does the SI 1014M) advise NOT to use ashless oils or oils with additives during break-in (except for turbos). Phillips, though, specifically claims that its X/C oil can be used for break-in. I'm skeptical, and have asked the mechanic to use Aeroshell 100 SAE50 for the break-in period instead. I figure that it can't hurt to use a straight mineral oil since this method seems to be true and tried for non-turbo engines.

Am I over-reacting? Is Phillips X/C OK to break in non-turbo engines?

Not at all how I was instructed to break in IO320s by Zephyr engines , rated tops by Aviation Consumer. Rings seated within a few hours and still get Great oil sample reports from Blackstone.

 

Thanks for your replies.
I just got off the phone with Dan at CCS. He told me that they test ran the engine for about 45 min in the shop with Aeroshell 100 in it. Then they drained it (and all the ring filings) prior to shipping. As to the Phillips oil, he said that he'd be fine with Phillips M type oil. The "M" is important. I assume that since X/C is also mineral based, it would be OK; but since they already used Aeroshell 100 initially during their test run, I'm just going to stick with Aeroshell 100 SAE50 for the first 50 hrs or so. I won't be flying the plane until July, so I'm not too worried about low ambient temperatures.

If you are not flying the plane until July, you better pickle it or you will have corrosion issues. Without a good varnish on the internal parts (gained after about 100 hrs of use) your engine can and will rust overnight if the conditions are correct!
Also, you may want to verify the breakin proceedures. The short run instructions are for an engine that has not been run on a test stand. You should be taxiing out and taking off with little delay and flying around the airport at high power (75% or more) until the CHTs stabilize and then land and check things. Let everything cool, then do it again and from then on operate for the next 10 hrs or until oil consumption stabilizes at high power. From there you can change oil to whatever you want and operat normally. If you don't run high power, you will not get a good cyl run in and you will have to pull and hone and start over.
Zach

Zach,
Thanks for the pickling recommendation. I'll ask the local mechanic to do that (I wonder if the engine has been pickled for shipping). After having spoken to CCS, I figured that the "break-in" instructions I received from the front desk person were most likely the protocol used by the technicians at the shop and not the instructions for the pilot. Dan, at CCS basically told me to do what you're saying: High power settings (75% or higher frequently varying power within that range), running a bit on the rich side, minimal time at low power. Land and check things after an hour.

Several overhaul and cylinder shops now recommend Phillips XC from day one on. My personal opinion is to go with straight, non-detergent oil for at the very least 10 hours. Do the break in schedule as Zach stated. You should be able to tell when the rings seat by the CHT variation. By 25 hours the oil consumption should be stable and you can then switch to whatever oil you plan on running full time.

As far a pickling the engine, I would either pickle it or get someone to fly it at least weekly to try to get the 25 hours as quickly as possible.

After the overhaul of my IO-540 in my Cherokee Six a couple of years ago I pondered the right oil to use for break-in. My mechanic said use the Phillips XC oil. I read up on it and then followed his recommendation.

After engine install we did a ground run up, shut down and checked for leaks. Then it was taxi out and take off, staying in the pattern using high power settings. For the next few days I repeated that process with high power settings and staying close, just in case.

At 10 hours we changed oil. At 25 hours we changed oil. After that it was normal flying with oil changes at about 50 hours. At 100 hours the shop that did the overhaul did a bore-scope inspection of each cylinder. They were impressed by how good everything looked.

From then on the engine ran like a top, low oil consumption and smooth power with even CHT's across all six cylinders.

The XC oil worked great for breaking in the engine and as the regular day to day oil, as Phillips claims.

- Bill

In conclusion, it sounds like both, X/C and straight mineral oil can be, and have been, used successfully for break in. So, it ends up boiling down to what oil the overhaul shop feels comfortable with and won't void their warranty. If the shop is fine with either, X/C sounds like a good option. Based on what my O/H shop has said, and used for the test run, I'm going the traditional route (straight mineral).

20 years ago a Lycoming rep told me that new engines were being shipped to the OEM's with Phillips 20/50 XC in them. They worked with Phillips to develop a multi-weight break in oil since they did not know where or what time of year an engine might start its life. I have used 29/50 XC ever since.

As an aside, the guys at Central Cylinders have a lot of experience maintaining the Rolls Royce Merlin V-12 and spend a lot of time helping maintain the Merlin in ! They are a great group!