Breaking in a new engine

nypilot88

nypilot88

New Member
Hey guys I know you would know a lot more then me:rawk:
I am currently breaking in a new Lycomings engine for the flight school I work at, It's a Cessna 152, Lycomings engine, carburetor, I've followed all the directions as far as keeping a shallow climb out for maximum cooling, 75% cruise power for an hour, alternating 65% and 75% cruise power for the last hour, flew it at it's recommended altitude of 5000ft and keep power in on the descents. Is there anything else I should be doing as far as ground run up or any other areas of flight or any tips at all. Thanks in advance guys.
 
I've broke in a few. The idea is to get max HP as much as possible during the break in. I wouldn't take it to 5000 unless I was in DEN. I'd keep it as low as possible and run it balls to the walls. The main thing is oil consumption. It's important to pay really close attention to how much oil it showed on the preflight and then how much it shows after each time you flight it. If it isn't burning any oil, then it's broke in. I once flew a 172 in circle over and airport for 10 hours. Later, I met a mechanic that said if the oil consumption stabilized in an hour, then it was done.
 
The manufacturers generally look for a stabilization in oil consumption. That being said, I wouldn't rush the subject. A few extra hours now may mean 100's later down the road.
 
Follow manufacturer's break in procedures and keep an eye on the engine gauges. Oil temp & pressure would be the main concerns but cyl head temp could be your first indication of a problem such as some baffling working loose after the inital test flight. Also do a good post flight inspection so any issues can be brought to the attention of maintenance as soon as possible. Keep your landing options and your eyes open, just in case.
 
I have the following tips for engine break ins.

- Eat a light breakfast, you think better when you're well fed, but don't eat too much.

- Ground run time is the enemy, do your run-up on the fly and get into the air as quick as possible. I don't really have the luxury of lots of landing spots here, so this is the only one that makes me pucker... But it is better to get into the air where the cooling is than try to keep a climb going with oil temp redlining because you spent too much time on the ground. I get the ATIS prior to engine start and pre-coordinate with the tower about what I want to do. In my case it's usually right hand circles just east of the airfield at 4000. This puts me in the perfect position to make an approach and landing dead-stick.

-Do a thorough pre-flight. Both the airplane and the books should be in order. Chances are an annual was done at the same time as the engine and the airplane may have been sitting for a while. I once showed up to break in an engine and found the left aileron disconnected... Your face will be red if you miss that.

- Review emergency procedures prior to flying.

- I write Vy and Vg for my weight on the back of my hand cuz I want em where I can find em.

- Limit the first flight to ONE HOUR ONLY, over the field and circling, I don't want them to have to come find me as a pilot. I don't want to have to come looking for you as a mechanic. The only time I was talked into a flight longer than one hour was the time the oil filter adapter cracked and I landed with 2 qts. left. Which brings me to my next point.

- PAY ATTENTION, was the oil pressure gauge at that spot 20 minutes ago? You don't know because you weren't watching. This isn't the time to bring a book to read. Yes, it'll be boring.

- Keep an eye out for the normal stuff too, I once had carb ice on a break-in flight... you can bet I wasn't thinking carb ice when the engine started to run rough, but carb heat cleared it right up.

- Go to the bathroom beforehand! It's hard to look like a hero with a stain ;) And besides, the more comfy you are the sharper you'll be.
 
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