Is My Engine Broken In?

macrafic · #1 11-27-2017, 09:54 AM

Background: Just completed RV-7A. IO-360 engine new. Started with 7 qts of oil, with the assumption that the better part of 1 qt would go to the oil filter. At 2.0 (tach)/3.5 (hobbs) hrs, I added a quart of oil. Probably could have waited another 2-3 hrs, as not quite a quart had been consumed. I now have 13.8 (tach)/16.8 (hobbs) hrs and am not needing to add additional oil yet. Maybe another couple of hours? So, in summary, I have 11.8 (tach)/13.3 (hobbs) hrs on this last quart of oil.

CHTs are behaving, but I did not unfortunately record the very initial CHTs at a particular power setting for a current comparison. As a result, I don't know if I have experienced the 50 degree drop in CHTs that I have heard about (as another indication that the engine has broken in).

In trying to summarize the various VAF posts on oil consumption, it seems to be the general opinion that 10 hrs per qt is a pretty decent consumption. Obviously, some are getting less and some more than that. So, I am definitely above that. I have read Lycomings documentation, but they only specify the max allowable oil consumption, not a desirable range. They also only specify a maximum schedule for mineral oil (25 and 50 hrs), with a stipulation that the key criteria is stabilized oil consumption.

So, the questions I am pondering. With so few hours, could the engine already be broken in? The oil has gotten much darker the last couple of flights, so I would like to change it. Should I again use mineral oil or go to standard oil?

Anybody have any other perspectives/thoughts/experiences that I should contemplate as I make these decisions? Any thoughts welcome.

flyinga · #2 11-27-2017, 11:05 AM

I just put rebuild Ram cylinders on my TCM IO550. Ram says cylinders will be broken in after 1st hour....and they were. CHTs down (not nearly 50 degrees!) and stable oil consumption. You do run it hard for that hour.

Raymo · #3 11-27-2017, 11:38 AM

Sounds like the cylinders (rings) are broken in but the rest of the engine may still be in progress. I would suggest (based on MFG recommendations) you stick with mineral oil for the first 25 hours. Change after the first 10 then after another 25 (total of 35).

I started sending samples to Blackstone after the 3rd change at around 85 hrs.

JonJay · #4 11-27-2017, 01:14 PM

Keep in mind that many of our engines will not hold 7, even 6, quartz without puking some out the breather. So, until you learn where your stable oil level is, oil consumption can be hard to judge.

Pat Stewart · #5 11-28-2017, 04:50 AM

There of different thoughts on this but here goes. On a New Lycoming I like to change the oil after the first five hours and the second oil change at 30 hrs total time. I am also a big advocate of doing a oil analysis. Every engine is different but it seems most will blow out oil over 6 1/2 Qts on the stick.

Berchmans · #6 11-28-2017, 11:57 AM

This can be like the debate between tail wheel v. nose wheel, but here goes. My YIO360M1B was purchased new from Lycoming and came "Broken In", it was run in the factory and ready for use on recept. Nothing in the way special treatment was require. I did change oil after 5 hours and now after 150 hours engine has no issues.

I have also had 4 engine overhauls done on various engines by the same local shop. A Continental O300, 470, and two Lycoming 320's. The overhaul mechanics break in recommendation was the same for all these engines. Minimal run up on the ground, full power climb to 10,000 feet, powered descent to landing. Change oil....break in complete. Some may agree or disagree but none of the engines have developed any problems in their service so far and the hours vary from 500 hours to 2,100 hours in service.

bkervaski · #7 11-28-2017, 11:57 AM

https://www.lycoming.com/content/har...t-engine-break

macrafic · #8 11-29-2017, 04:32 PM

Appreciate all the feedback guys. I really do.

However, several of you pointed to the Lycoming documentation, which I have read. The operative phrase in that documentation, after stating hours, is "or until oil consumption stabilizes". I am trying to figure out what to look at to determine that.

While each engine is different, maybe the key here is, how many hours have others taken to break their engine in? Is there a number or a range that seems to be the case, with exceptions of course?

sglynn · #9 11-29-2017, 04:41 PM

I installed new O-540 2 years ago. First hour was critical to run hard at low altitude to burn rings into cylinders. Next 10 hours still ran just straight mineral oil and considered it break in time. After 50 hours oil use is low but compression's were 76, 77, etc Switched to mineral oil with additive. And now 100 hours later it uses very little oil and compression's are 78, 80 etc. I think it kept breaking in for the first 100 hours and now it is tight.

Ironflight · #10 11-29-2017, 05:25 PM

Quote:

Originally Posted by macrafic

Appreciate all the feedback guys. I really do.

However, several of you pointed to the Lycoming documentation, which I have read. The operative phrase in that documentation, after stating hours, is "or until oil consumption stabilizes". I am trying to figure out what to look at to determine that.

While each engine is different, maybe the key here is, how many hours have others taken to break their engine in? Is there a number or a range that seems to be the case, with exceptions of course?

I've seen engines with an hour and half factory run-in that broke in within an hour of flight time, others took five, others took ten....and some just keep burning oil.

In reading your original post, I couldn't get a clear picture of how much you are burning NOW. If you keep tripping it to 7, as you stated you put in up front, then you're pumping oil out the breather, not burning it. So now if you start at 6, how long does it take to get to 5? If that's 10-12 hours or more, you're probably done.

This is assuming standard Nitrided cylinders. Other cylinder finishes can vary widely.