Is it broken in?

[Michael Henning]

I am running an ECI IO-360, Cerminil cylinders(group "A"), 9.5/1 pistons. 3.3 hours on engine so far. CHTs were in high 300s at beginning of first flight and were coming down to mid 300s by the end of that 30 minute flight. Running mineral oil for the first 5 hours, then switching to multi-weight oil.

The CHTs have stabilized at 325 degrees (cylinders 2-4 are all within 10 degrees of one another) and cylinder #1 is running at 285 degrees. The power setting is 25" MP/ 2500 RPM. I am planning on balancing the injector nozzles to bring up the #1 CHT.

Thoughts/ Comments? Is this engine broken in? It has burned less than 1/2 qt, and not burning any now.

[Jesse]

That sounds pretty good to me. If anything, maybe not hot enough. It's hard to judge oil usage in 3.3 hours. You want it to be using some. It should go through a quart every 20 hours or so.

[Michael Henning]

Thanks Jesse. I am now able to really start flying it, so I will have more data to make conclusions. I had the prop "balanced", from the factory it was .07 IPS, and the tech wasn't able to get it any lower than that. It is very smooth.

[RV10inOz]

The power setting is 25" MP/ 2500 RPM. I am planning on balancing the injector nozzles to bring up the #1 CHT.

Michael,

First of all, engine break in is usually over in the first few hours. 5-6 is enough and by the 10 it is most surely. I hate people using the old 25/2500 as being some kind of perfect setting, but in any case this will have given you about 80% power when ROP. I assume you left it full rich. You could have done in LOP but used 27"/2500 and achieved the same power but cleaner and slightly wider range of average pressures, but that is not the question here.

Please DO NOT do this: "I am planning on balancing the injector nozzles to bring up the #1 CHT" as this is a REALLY bad idea.

This is akin to saying three of my tyres are a bit more worn than the 4th one so I will let 20PSI out and wear it down to match the others.

Balancing your cylinders is all about matching the Fuel/Air ratios. That is getting a good GAMI spread, for you that is about 0.3 GPH between when the first EGT peaks and the last one peaks. 0.5GPH is the line in the sand but I find on the 4 cylinders you want to get more like 0.3.

This then gets the engine working right. The HEAT IN part of the equation is fixed. Now is the time to look at baffles and getting the CHT's at a reasonable level in climb and cruise. What is reasonable? A big rubbery zone, but if I use my RV10 as an example it would rarely get above 380 in the climb except on a very hot day and not by much, and once cruising around 355-370 if ROP and 325-350 LOP on a hot day and about 15 less on cool days.

If you get your CHT's within 25-30df of each other and they are all good. Life is good. Dan Horton has good posts on baffles etc.

If what I wrote above is not 100% clear, PM me so we can discuss it. Never ever monkey with injectors to fix a CHT.

[cajunwings]

You may be mostly broken in but 3.3 hrs is very early in the game. I would be leery about switching away from mineral oil too early. What I recommend to clients and on my own fresh OH IO320 is 10 hrs on mineral oil then change the oil & filter. Put mineral oil back in and fly another 20 to 40 hrs before changing to whatever oil you will run after break in. I consider the engine broken in when the cht's, oil consumption & wear metals all have stabilized. There is no downside to running mineral for 50-100 hrs but a possibility of jeopardizing the break in by switching too early.

Don B. A&P. IA

RV 9. Rebuild in Progress

[flyingriki]

Ly-Con says the same about oil. Keep mineral oil for a lot longer than 5 hours......

[Robert Anglin]

This is just me and not out of any book. I like to think two oil changes for break-in. The first at 10-15 hours the second 20 hours after that. If all the temps and oil consumption settles down by then and you don't see any thing in the filter after the second oil change then have at it and go on a regular bases by the book. I would not start adjusting fuel flows unless one was way out of line until at least 50 hours into the hobbs time on a new engine. It is your engine and your call, but old school has served us well in the recp. market for a long time. Yours most respectfully. R.E.A. III #80888

[Captain_John]

Michael, It has been pretty cold around here lately. I have been watching my CHT's pretty close lately too. I am interested in seeing what happens when things start to really warm up around New England. Maybe we can meet for breakfast or lunch and chat about it.

Shoot me a message.

CJ

[Michael Henning]

Thanks for all of the replies, I really do appreciate it. as I am not an engine guy. Dave- I spoke with Don at Airflow and he is going to work with me on balancing the injectors and I am reading DHs posts on baffling.

[Bill Dicus]

New Lycoming engines from the factory are broken in before shipping. Nevertheless, Lycoming says continue mineral until 50 hours of operation. Might be good to wait a bit before going to multigrade detergent. Let us know how it all works out. Wish mine broke in so rapidly!