Aside from Melting the piston to the sleeve, what are some of the other damages you can do to an engine from improper running(breaking) inaNEW engine?

As long as you have a good fuel, it is hard to foulup the modern day ABC (N) engines

The biggest problem is heat from running too lean especially with all synthetic oils. The temperature of the liner surface (in particular) can get high enough to boil off the oil film which leaves no lubrication for the piston. Also a very lean run sends the temperature of the wrist pin above the boiling point of synthetics so the rod runs dry on the wrist pin. Some castor can help for a short time.

Or you can run them slobbering rich like some folks, the engine never reaches operating temp, and the pinch at the top of an ABx engine hammers the rod down on the crank pin every stroke.

That's an hearsay only and you don't want to go there....

Not sure whats hearsay. They are designed to expand when they get hot, if the top doesn't expand then the piston gets pinched on every stroke.

People come out to the field with a never run engine and if the engine runs pretty good, it goes in the air. That was the break-in, did you miss it?

That's the way.
I just ground run a couple of rich tanks, then fly a slightly rich.
If it starts leaning out, land adjust and take off straight away.

Just listen, if you're not experienced enough to hear the difference, fly with someone that is and ask their advice.
The worse thing that people fear is a dead stick. If the sound of that frightens you, you need to practice.
If you have a decent flight plan/routine work out, a dead stick anywhere won't be a problem... only an annoyance!




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To run the engine rich are not a good idea to running in the engine, the engine need temperature to expand the sleeve from taper to parallel. The modern engine with ABC/ABN piston/sleeve do not need a couple of rich tanks as in older iron engines in old days.

The engine get drops of oil out of exhaust (a little of smoke) + hot enough to touch the cylinder head means the engine are in good working temperature + enough oil to lube the engine parts.

The engine need tapered sleeve to keep compression when the engine are cold and will improve starting and do not need tapered sleeve when the engine are allready in use since there are enough to keep compression in a short time between each turn of crank rotation while the sleeve are in parallel.

Very few engines are so tight that they'll pinch when flipped over quickly with a glow plug installed. A running engine will not have the cylinder at ambient temperature even when running rich.
"Downunder" has already tested, and disproved, the danger of running an ABC rich in a another long thread on this forum....

So,  you really can't do any damage except seize the engine by improper running in?
Improper running procedure's will not make an engine hard to fine tune?
As long as you don't melt the piston and sleeve together the break in procedure is correct?
 

I appreciate the guys who buy a good engine, mount it on a plane, bring it to the field and try to fly it on the first tank. Never really works out for many. If they do get in some flights they complain about the lack of power from that piece of @#!%%^[:@]. I have bought some of those and ran them long enough to become good strong engines.

You can not damage the engine if the engine are not leaned out to oil are bursted by heat of friction cause not enough oil are entered into the engine.

You can not melt the piston, the aluminium will melt about 550-650 C degree (1022-1202 F) and oil are limited to 300 C degree (572 F) for castor oil and lower if syntetic oil are used as lube. But the surface will be damaged by abration and friction in case there are no oil there.

Reading all these posts and back the the OP's question.....the conclusion is to run it normally. Get the engine to were it is not to rich, and not to lean. Modern engines will break in naturally if you adjust the needles correctly. Do I add not giving it WOT for the first few tanks?

You should consider this also, with a little care at break in, you will have a engine that makes more power and lasts longer than one that was neglected during the break in period.


Do you suspect that you have damaged your new engine? Is that why you ask this question?

Rotten,


If that new engine you have has a tapered-bore sleeve (ABN/ABC/AAC) and a ring-less piston; just follow the procedure outlined [link=http://www.rcuniverse.com/forum/m_1850473/tm.htm]here[/link].

A while ago I did an impromptu test on this. I had a new engine which had the tightest pinch I've ever felt, so tight I found it impossible to flick through TDC, it simply locked up. I considered lapping in the piston but in the end I decided to just try running it and see what happened to the rod. The thing is, this wan't an ABx but had a cast iron piston and steel sleeve so not only had to be run very rich but there was no possibility of heat expanding the liner. Because I couldn't hand start it I had to use an electric starter which had great difficulty getting the piston through the pinch but eventually it managed it just enough for the engine to fire and run slobbering rich at 6000 revs. For about the first 40 minutes, every time it stopped the piston would lock into the pinch and at about 60 minutes I could finally hand start it. It's now got around 90 minutes of 4 stroking and feeling very nice indeed with no detectable play in the conrod and the piston/liner look perfect. Just for interest's sake, at those low revs the head temp was 125F which is the coolest I've ever seen .