new engine

[scopiton]

what are the damages a new 200hp injection lycoming can have if not operated with moderation during the very first 5 hrs ?
when i say not moderation it is above the 35% BHP recomended
thx

[cgzro]

I've not seen 35% BHP as recommended limit during break-in, infact thats not enough to stay airborne for most A/C!!

Most break-in info I've seen recommends flying relatively high power settings so that the rings will seat properly, i.e. high cylinder pressures. Go to the Lycoming website and lookup break-in.
I think you have it backwards.

[scopiton]

yeah thats what i thought 35% is quiet weack
I'll have a look on the lyco site

[cgzro]

Was just googling lycoming for other stuff and found the reference.

http://www.lycoming.textron.com/support ... ations.pdf

And here is the relevant text:

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.

[iflyforpie]

In addition to what cgrzo posted there are sometimes specific break in instructions depending on what kind of cylinders you have. A Cermi-Nil cylinder for example requires you to steadily increase power over a certain period of time.

Basic break in methods involves using high power settings (while monitoring CHT/Oil temp to ensure they don't get too high) and not running at a constant power setting for the first few hours. I change oil after a 2 hr break in flight and then switch to ashless at the 25 hour mark after checking leak downs.

A guy I knew had an Acro Sport with an O-290 he just got overhauled to put in the plane after he built it. Unfortunately it wasn't a plane you could get dual on so he spent a ton of time taxiing around before he flew it. He was wondering about excessive oil consumption and I did a leak down on it and every cylinder was below 50/80.

[scopiton]

great for those infos
owner was freaking out but all your saying is rassuring
cgzro, I also checked lyco site and there is a ton of good infos there
the ops pdf and maintenance are very usefull

thanks again

[Hedley]

he spent a ton of time taxiing around before he flew it ...
excessive oil consumption ... every cylinder was below 50/80

It's amazing how many people think that "babying"
an engine is good for it

Breaking in an engine is all about seating the rings,
and that is accomplished with cylinder pressure -
lots of it.

Of course, you want to make sure that your oil
temp and CHT don't climb too high, but if everything
is set up properly, that shouldn't happen.

Run it hard, and you will be rewarded with an
engine with 79/80 on every cylinder, which means
more power, and less blow-by to contaminate
the oil.

You simply wouldn't believe how I run my
engines, and they always have the best
compression numbers at the airport.

It doesn't hurt an engine to create torque
at rated RPM The important thing
is to keep the oil and CHT temps down. If
the metal gets hot, it's not going to last as
long. This is not rocket science.

N.B. I run the best oil I can buy - Aeroshell
100Wplus (sae 50) in the summer, and
Aeroshell 15w50 in the winter. I change it
frequently, and always run it at full. Most
owners don't bother with any of the above.

[scopiton]

and what about circuits with frequent changes in temp and power ?
if i believe what you say Hedley it should be OK

[Hedley]

Don't fly circuits when you're breaking in an engine!!

For Christ's sake, for what an engine overhaul costs,
you can afford to fill the tanks and push all the knobs
all into the dash and leave them there until you're
down to a half-hour of fuel remaining. Just drive
around in circles around the airport below 2,000
feet to keep the manifold pressure up, and in case
you have to land in a hurry.

If you just do the above, the rings will be seated
and the engine will be broken in, when you touch
down after the first flight. Watch the oil temp - it
will suddenly drop - the rings have seated.

This procedure is applicable to a jug change, as
well as a complete overhaul.

[cgzro]

great for those infos
owner was freaking out but all your saying is rassuring
cgzro, I also checked lyco site and there is a ton of good infos there
the ops pdf and maintenance are very usefull
thanks again

The only thing likely to suffer if the break in is not done properly is compression. That will result in more blow-by so more frequent oil changes, also an increased tendency to foul the lower plugs.

So even if it were screwed up, you could live with it for many years, just change oil more frequently, lean aggressivly on the ground to avoid fouled plugs, etc. would not be the end of the world although would probably lead to an earlier top overhaul.

Dont' sweat it. Just fly the crap out of it. Lycomings like to be used used used and frankly the weakest part of that engine is the camshaft and lifters. If they are not flown every week they will rust and lead to a premature rebuild.

Fly fly fly, and enjoy the upcomming but temproary drop in fuel prices

[scopiton]

thanks hedley for those infos

cgzro yes we actually fly I do the xxhrs insurance requested to survey a private who just bought an aircraft, so i don't really freak but woul like to informe him correctly

that's a new knowledge, thank you