Thorp Air Command - T18.net

A new Lycoming cylinder was just bolted on last Friday in the number 3 (odd, like me) position. I have followed the Lyc break in procedures to the letter so far with 2 flights totaling 1.5 hours at full throttle as low as I can go. For those outside the know, the short version is...Lyc wants you to load the piston/cylinder in order to get the rings to seat properly and without glazing the cylinder walls. Home field elevation is 4600 with DAs of 5500-6500 this time of year during the day. Lyc wants their engines/cylinders broken in at 75% power thereabouts - at full throttle 1000 AGL with a DA of 6500 at the field elevation, I am barely pushing 75%, and Lyc wants you running at 100 ROP to keep it a little cool. The (majority of) articles I have read state that one should run the aircraft down low (5000 MSL) at 65% to 75% for anywhere from 10-50 or better hours to properly break in this cylinder.

So here is my dilemma - I'm high........that too....ahem....I live at 5000 tootsies MSL and routinely fly at 8000-11000 MSL and will usually fly up at FL13 and change on the way to KVIS for 10 minutes this weekend over the Sierras.

Do you engine wiz bangs out there (strongly) recommend I stay low IFRoads long way around the Nevada mountains on my way to KVIS? (means a mean alt of around 7500 MSL at 1000-1500 AGL)...and all the while cranking out 65-75% power.

Or do you folks think it is OK to take it to the cool air and save a ton of gas?

All advice welcome, as there seems to be some conflicting stuff out there from minds far brighter than mine.

_________________
Fraser MacPhee
N926WM
Serial #279-1
Angel Fire, NM (KAXX)

Frase,
My understanding is that the first hour is critical after that they just want you to keep running it at a consistent high power setting (no formation for a while buddy). Really the rings should seat after that first hard hour, the rest is just getting the oil consumption down, which yes, does mean more "seating" but as long as you're running it at the best % you can consistently you should be fine.

_________________
Lee Walton
Houston, TX
N51863,N118LW
KEFD

Fraser...I suggest you drive .

RB

Well, after a little more research, it appears that per the Lyc manual, with the power up and the RPMs up at 2600, I'm good to "pressure" altitudes of 11K while pushing 68% power - that won't keep me completely on top of the line of flight insitsu cummulo granite, but it sure shortens the distance and improves the fuel economy making it a one stop hop vs a two stopper.

Thanks Lee - if anyone else has sage advice or experience breaking in an engine, bring it on.

_________________
Fraser MacPhee
N926WM
Serial #279-1
Angel Fire, NM (KAXX)

Put the Throttle to it Frase, by the time you get here she auta be good......Dan

When I bought my engine, close to 30 years ago, it was brand-new from Lycoming (via Wag-Aero, for somewhere around $5140.00, I believe). I would have a hard time believing they ran it for more than an hour on a test stand at the factory. You know the altitude here in Denver. I didn't do anything special... just ran it, including plenty of 10 to 12 k flights during the first 40 hours. That engine still uses only a quart of oil in 25 hours, with about 1300 hours on it. If your cylinder doesn't break in properly, I don't think it would be for that reason, but what do I know. Just my 2 cents worth.

_________________
John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE

I will never forget a story that one of our instructors told us in A&P school many years ago. He got a new engine in for one of the fleet aircraft and for some reason it had never seen the test stand. They broke that engine in in the air, and it turned out to be the most trouble-free engine they ever had.

FWIW

D

This might provide some useful info . It came with my zero time Aero Sport Power 0-360 .

RB