New (rebuilt) engine break in

N9657 · Post by **N9657** » Wed Jan 20, 2010 12:29 pm

I just got my factory limits rebuild back. Any suggestions re the breakin technique. Its a Lyc 0-360 c1F in a 1980 M5
Thanks

MauleWacko · Post by **MauleWacko** » Wed Jan 20, 2010 1:01 pm

N9657 · Post by **N9657** » Wed Jan 20, 2010 1:16 pm

The shop that did the install was very casual about it. Said to run at 70% power as much as possible, vary the power a little every 20 minutes, change the oil at 10 hours. Do not do much low power flying for the first 5-10 hours

a64pilot · Post by **a64pilot** » Wed Jan 20, 2010 2:29 pm

Lycomings recommendations are in here. http://www.lycoming.textron.com/support ... enance.pdf
I think you will find that they probably parallel your shops recommendations, but a whole lot more wordy.
Me, I run the snot out of them, but keep them rich and therefore cool, and shallow climb angles, high airspeed = cooling.
Worst thing you can do is baby it, if you do it will burn oil and not live as long.
Big key is don't let it get hot
I change the oil before I fly one, then at 5 hours, then 25, then 50. Oil is cheap and easy, and I want the metal out ASAP and I figure oil is cheap. Run it rich too for at least the first 25 hours, rich = cool

maules.com · Post by **maules.com** » Wed Jan 20, 2010 2:32 pm

Add to that, don't fly much above 5000msl or you cannot get optimum manifold pressure to help push the rings against the cylinder walls.
Open the oil filter with the oil change.
Rumour has it that it takes an hour of flight with oil temps at minimum of 165 degrees to gas off the contaminants produced in one startup and shut down.
It is difficult to get the O360 Lyc up to 165F in winter especially.
Make sure the baffling is sealing and that all side and front cylinder baffles are UP. Make sure you have the full coverage of bafflinf that hooks around the alternator and ring gear at right front. Many times I see it missing because the fiberglass breaks away. You can cover that area with baffle material if you don't want the awkward piece of cowling in the way of cowl removal.

Maulehigh · Post by **Maulehigh** » Wed Jan 20, 2010 2:32 pm

The Lycoming Flyer is available on the internet and the one titled 'Operations' details engine break-in as:

"A new, rebuilt or overhauled engine should receive the same start, warm-up and preflight checks as any other engine. There are some aircraft owners and pilots who would prefer to use low power settings for cruise during the break-in period. This is not recommended. A good break-in requires that the piston rings expand sufficiently to seat with the cylinder walls. This seating of the ring with the cylinder wall will only occur when pressures inside the cylinder are great enough to cause expansion of the piston rings. Pressures in the cylinder only become great enough for a good break-in when power settings above 65% are used.
Full power for takeoff and climb during the break-in period is not harmful; it is beneficial, although engine temperatures should be monitored closely to ensure that overheating does not occur. Cruise power settings above 65%, and preferably in the 70% to 75% of rated power range, should be used to achieve a good engine break-in.
Remember that if the new or rebuilt engine is normally aspirated (non-turbocharged), it will be necessary to cruise at lower altitudes to obtain the required cruise power levels. Density altitudes in excess of 8000 feet (5000 feet is recommended) will not allow the engine to develop sufficient cruise power for a good break-in.
For those who still think that running the engine hard during break-in falls into the category of cruel and unusual punishment, there is one more argument for high power settings during engine break-in. The use of low power settings does not expand the piston rings enough, and a film of oil is left on the cylinder walls. The high temperatures in the combustion chamber will oxidize this oil film so that it creates a condition commonly known as glazing of the cylinder walls. When this happens, the ring break-in process stops, and excessive oil consumption frequently occurs. The bad news is that extensive glazing can only be corrected by removing the cylinders and rehoning the walls. This is expensive, and it is an expense that can be avoided by proper break-in procedures.
To summarize, there are just a few items to remember about engine break-in:
1. If a preservative oil has been added by the aircraft manufacturer, drain it no later than the first 25 hours of operation;
2. Follow the engine manufacturer’s recommendation regarding the oil to be used for break-in and the period between changes;
3. Run the engine at high cruise power levels for best piston ring/cylinder wall mating;
4. Continue break-in operation for 50 hours or until oil consumption stabilizes. These simple procedures should eliminate the possibility of cylinder wall glazing and should prepare the engine for a long and satisfactory service life."

Hope this helps

Regards

aero101 · Post by **aero101** » Wed Jan 20, 2010 5:52 pm

Ditto, 70 - 75% power varying occasionally on long cruise, no extended ground runups as high temps not needed... No touch and goes. Once obstacles cleared on takeoff, put the nose down a little for cooling air speed. Try to get oil temps up to 180 - 190 range, in any case, keep them above 160... Should see drop in oil consumption, cyl head temps within 20 - 25 hrs at which time the rings will be seated, from there just keep temps within limits and don't baby it, 70 - 75% is what this engine likes!!! Just finished break in on mine, took about 18hr for oil consumption drop, runs like a champ!!

N9657 · Post by **N9657** » Wed Jan 20, 2010 6:39 pm

Seems like everyone's advice corosponds with what my mechanic said. Thanks for the input.

Skystrider · Post by **Skystrider** » Thu Jan 21, 2010 9:12 am

N9657, A couple of months ago I had my 360 in my 1980 M5 rebuilt also. Since then I have noticed a good 8-10 MPH increase in cruise. I would be interested in knowing if you see a speed increase.

Good luck with the "new" engine!

a64pilot · Post by **a64pilot** » Thu Jan 21, 2010 2:38 pm

I think your speed increase is a function of colder, denser air more than anything else. If I'm right, then this summer you will see a speed decrease.
If you calculate true airspeed, there difference should decrease, or at least mine does.

Skystrider · Post by **Skystrider** » Fri Jan 22, 2010 6:56 am

a64pilot wrote:I think your speed increase is a function of colder, denser air more than anything else. If I'm right, then this summer you will see a speed decrease.
If you calculate true airspeed, there difference should decrease, or at least mine does.

I agree with what you are saying A64 but I got my airplane back early last September. We weren't into the winter season yet. I just figured it was because I put on larger tires!

N9657 · Post by **N9657** » Fri Jan 22, 2010 12:05 pm

Skystrider wrote:N9657, A couple of months ago I had my 360 in my 1980 M5 rebuilt also. Since then I have noticed a good 8-10 MPH increase in cruise. I would be interested in knowing if you see a speed increase.

Good luck with the "new" engine!

I noticed the same thing the other day. I was amazed. I am going on a 1 hour trip with the NE Flyers tomorrow to KRDG and will pay more attention. At 24 squared I would do an indicated of 128 mph, yesterday I was doing 135. I have had this plane over 3 years and winter or summer never exceeded 128- 130 mph. If you can make it to KRDG on Saturday around 11:00 11:30 am it would be fun to meet.
Jerry

a64pilot · Post by **a64pilot** » Fri Jan 22, 2010 2:34 pm

Mine trues out between 132 and 136 KTS between 9 and 11 thousand.
I have not been able to figure out why some days there will be a 4 Kt. difference, there just is.

aero101 · Post by **aero101** » Sat Jan 23, 2010 10:03 am

Fresh engine, more HP, takes more pitch in prop to hold same RPM= faster cruz... If the old engine was really tired, you'll notice a good difference in cruz speeds under same conditions... Sounds like you got a good engine in there now!!!

Skystrider · Post by **Skystrider** » Mon Jan 25, 2010 6:55 am

Sorry Jerry, I didn't see your message about Reading until Monday morning! You probably flew just about over my airport! Saturday was a great day. I spent most of the time just flying around with friends.

So, you are up in Orange County. A couple times a year I go in there for the "Runway Cafe". Come on down to the fly-in we are having on June 25th thru 27th. A wild weekend of flying, camping, girls and booze! Well, the first two anyway!

Interesting that we both are seeing a good increase in speed after the engine rebuild. I sure am not complaining!

Rod

New (rebuilt) engine break in

New (rebuilt) engine break in

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