os 46fx break-in, being a newbie I read the manual on engine break-in......I was kinda confused that the instructions said to run it at full throttle on rich mix (four cycle sound), for ten seconds, then lean it out to two-cycle sound for ten seconds and repeat this procedure until you run a tank of fuel----back and forth every ten seconds.........I hear there are different methods of running-in a new engine.........I just want to know is this the preferred method....











flying is like breathing, everybody should do it........

My preferred method is to put the engine on a plane, fire it up and at the high end, make sure it is running rich and fly it. I leave it this way for about 4 flights and then do some high end fine tuning. I also use a fuel that has castor oil as a partial lubricant in it and this is the way that I have broken in engines for over 30 years. Good Luck, Dave

My preferred method is to put the engine on a plane, fire it up and at the high end, make sure it is running rich and fly it. I leave it this way for about 4 flights and then do some high end fine tuning. I also use a fuel that has castor oil as a partial lubricant in it and this is the way that I have broken in engines for over 30 years. Good Luck, Dave

Dave's method will work fine.
Now as to WHY OS recommends theirs. When you lean the engine it runs hotter than when it is rich. By doing it the OS way you do a number of temp cycles on the engine which aids in seating the piston to the sleeve.

OS did not take the time to write their manual just because some writer had nothing better to do one day. OS must believe THIS is the BEST way to break in their engine. They've probably only built a couple million engines, but I'm betting on them.

The preferred method for breaking in an engine is to follow what the instruction manual says. I know that's not the answer you're looking for, but that's the best advice.

Ken

thanks guys, also I would like to know if a muffler deflector will make a difference in the break- in, see-as-how I don't want to get my good looking "stik" too oily before her maiden flight. I had one on my .40 LA, on my trainer, and I was told that the engine would have to be tuned differently with the deflector..........if it is best left off, I would not have a problem with it.......














flying is like breathing, everybody should do it........

One of those short angled ones (about 2-3 inch long) won't hurt anything. A long pipe would change the backpressure. Deflector may cause you to change tuning by a click or 2, nothing worse.

I "broke in" my engine the OS way, acording to instructs. runs great no problems the only thing I changed after break in was the glow plug,I went from the #3 to a #8 seems to run a bit smoother, other than that haven't touched it.
follow the book you will have a solid reliable engine.and yes I did do the break in with the deflector its a non issue other than help to keep the slime off your plane. I have 2 of these 46's, a FX and a AX both run great and always start.

As you gain experience, you'll learn that OILY is good when it comes to glow engines. You'll also discover that the more oil you get on your plane in flight, the better pilot you become !

Seriously, don't worry about the oil. The deflectors are pretty much worthless on trainers. Just means the oil slick starts an inch or two further back.

Brad

I have two 46's, one 50, one 61, one 90, and three 1.20 OS's. I've followed the book method of break in and find that each and every one runs reliably and efficiently. The oldest engine is the OS 50, about 4 years old now, and it still runs just great.

As Bruce said, the main purpose of the changes in mixture is to allow the piston to seat in the sleve and to get a good match for the piston to the sleve in side the cylinder. The "large" amount of oil passing through the engine during the rich sessions will also help to flush out any flake metal that may exist or may form during the break in process. The oil may be slightly dark or almost black in color for the first tank but will eventually change to the color of the fuel you are using. I use S&W 15% which is a rose color. The oil the engine spits out is red in color.

As far as deflectors are concerned, well, I use them, but as someone said, they deflect the oil perhaps a couple inches back. It still will get all over the fuselage behind the wing and all over the tail feathers. The only exception is on my Venus II with the muffler pointing straight down (engine is mounted on an angle). With a deflector, I get a minimum of oil on the tail. It tends to deflect the oil enough away from the underside of the aircraft that I don't get much accumulation at all.

Stick with the manual and break it in right. It's worth the effort and, after three tanks or so, it will run just great and consistent, and keep running that way for a long time.

Don't over or under prop the engine either. Prop it to keep the RPM around 12000 at full throttle on that OS 46 and you will be a happy camper as to it's performance.

Sure do it the OS way if you want to be playing around with your needle valve every 10 seconds. Its much easier to run 2 tanks of fuel through it at around 1.75 to 2 turns on the needle valve, tune then fly. It may be the "best" way but it certainly isn't the smartest way.

You can do it however you like. I got good results following the OS instructions. Turning the needle valve a half turn every 20 seconds or so does not seem like that much of an effort to get good results, and I've had great results following the instructions. But, there is a seat for every butt. Everyone has an opinion and everyone's opinion is the best one. I don't see it as a waste of time for the length of time it takes to run two tanks of fuel through an engine, though.

DS.

Same for me--Also have a clear cut understanding of how the low end needle works will be a trememdous help. I personally feel the low end is the cause of most all engine problems

The original poster self states he is a newbe. I'm sure he/she has no idea about the interaction between the low end and high speed needles. If he is doing this himself, then he is best to follow the manual and do as OS states it should be done. Perhaps once he has learned a bit about the proper settings of both needles, then maybe he can do what you guys are suggesting. But, I am not a newbe and still follow the directions. 30 minutes of my time to properly break in an engine doesn't seem all that terrible a waste of time.

No.

What he shold be doing is reading this thread and following the directions there:
http://www.rcuniverse.com/forum/m_1850473/tm.htm

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Thats how you break in a new OS 46FX.

You DON'T break in a brand new ABC, ABN engine by running it sloppy rich on the ground for a couple tanks. Thats the worse thing you can do to it. It's a tapered bore engine and it needs to heat up to operating temps as quickly as possible. 4-stroking it for tank after tank when it's brand new is going to wear the pinch right out of it and put 3yrs worth of flying on it in the first 10 minutes of operation. It can't get warm enough for the cylinder to expand at the top. There's too much fuel in the engine and it cools the engine too much. If that tapered cylinder doesn't expand at operating temps--then all your doing is squeezing the piston up into the cylinder--thats too tight because it won't expand at cold temps. You going to knock the tops of the piston sides off and ruin the compression. Your risking unnessecary wear on the connecting rod because your squeezing the piston up and down in a cylinder thats too tight. Thats a good way to whaller out a rod end and ruin your engine real quick.

The days of 4-stroking engines for tank after tank on the bench are over. Thats an acceptable method for breaking in the old steel liner engines with ringed pistons or the old lapped cylinders.

But, all it does to a brand new ABC, ABN engine is ruin it.

FlyByMe:
Read that thread that I linked. THAT is how you break in your brand new engine properly. Don't run it sloppy rich and burbling raw fuel out the muffler. Thats a recipe for disaster.

Look;
OS has NO interest in your engine making maximum power. OS has no interest in your engine lasting 10yrs.

OS DOES have an interest in your engine NOT coming back to them for warranty repairs.

They reason WHY they tell you to break in your engine all stupid rich is because they KNOW your chances of ruining the connecting rod by running it overly rich are less than if you were to just start it and run it only 1/2 turn rich for the first couple tanks. They don't want it coming back in for warranty and having to replace your rod for free. So, they tell you to break it in rich because thats "safer" for the rod.

BUT, that overly rich setting might be super safe for the rod--it ain't no good for the cylinder and the piston. It actually ain't no good for the rod either. I already explained that earleir in this post, but I'll go over it again incase it didn't quite make sense.

The rod is taking a LOT of load when that engine is cold. That cylinder is smaller at the top than it is at the bottom. It's TAPERED. It's SUPPOSED to be that way. All the heat in the engine is right up at the top where the explosions from the combustion are happening. That heat from the explosions is what makes the metal at the top of the cylinder expand. It expands out and makes a precision fit with the piston. There is no ring on the piston. It gets the seal from the precision fit between the cylinder liner and the piston. The liner expands with the heat from running the engine at PROPER OPERATING TEMPS and then the piston fits up into the cylinder very tightly and thats where the compression comes from.

If you run the engine sloppy rich--then the cylinder liner can't get hot on the top. If it doesn't get hot, then it won't expand. If it doesn't expand--then your squeezing the piston up into the cylinder when the cylinder is too small.

Whats that do?

If REALLY puts one heckuva load on the connecting rod. Your squeezing that piston up into the cylinder thats too small. Then the rod has to YANK the piston back out of that cylinder when the piston goes back down. Squeeze it in--Yank it out. Squeeze it in--Yank it out. Thats a perfectly good way to absolutely RUIN the connecting rod. That little aluminum rod and bronze bushing can only take so much load for so much time before the hole in the rod starts to look more egg-shaped instead of round like it should be. Egg-shaped connecting rods don't last long.

The cylinder and piston is where the engine gets it's power from. You want all the compression you can get out of a stock engine. There's a way to break it in and get the best results. Get the best compression out of it when your done breaking it in.

Running the engine stupid rich doesn't allow the cylinder to heat up. When the connecting rod forces the piston up into the cylinder--it WEARS on the piston. Squeeze a 1" piston into a .990" hole and somethings gotta give. The aluminuim on the piston is softer than the nickel plating on the cylinder. It wears down. Now yank that piston back out of that hole that was too small to begin with. More wear on the piston.

It's NOT in your best interest to run that engine overly rich. It can cause all kinds of problems.

I buy a brand new gallon of OMEGA fuel with only 5% nitro in it. This fuel has 70% synthetic oil and 30% castor oil. Castor oil is GOOD for break in.

Buy a gallon of fresh fuel. Split it in half. Now add about 2--3oz of Klotz castor oil to each 1/2 gallon jug of fuel.

Break your engine in on that. The extra castor in the oil will provide a very large safety margin. You don't need to run the engine stupid rich to protect it. You've got a lot of oil in your fuel already. So, start it and run it up to max throttle.

Read that Tapered Bore thread. Break it in following the advice set forth in that thread. You'll be a lot better off in the long run.

Just exactly WHO in this entire thread said a single word about "sloppy" rich? Nobody that I saw. There is a big difference between varying from just into 4c and back into 2c operation. Not one single word was said about "sloppy" rich. I fully agree that would be detrimental. Nor did anyone say to do this for "tank after tank". Are you reading the same thread?

4-stroking a brand new ABC engine IS sloppy rich. Thats the worse thing you can do to it. Might as well just take it out of the box and smack it with a sledgehammer. Save yourself the trip to the field because the end result is goint to be the same. Ruined engine.

Well, we're just going to have to disagree then. IMO an engine that has JUST broken out of 2c is NOT sloppy rich. I've got many engines that have been broken in this way that operate just fine.

Fine.

I disagree with running engines overly rich during break in.

Agreed

Then he needs to learn and there is no better time than now. The manuals are designed to prevent lawsuits and full of confusing crap. If you break in an engine for 5 hours, it's not going to be anymore ready to go than if you do it for 5 minutres on the plane and fly it if you don't know how to tune it properly.

I guess my OS 61 SF that is at least 10 years old must not run.. but it makes noise as though it is. And it has plenty of power to pull along my Tiger 60 just fine. It was broken in as the directions stipulated and as we've been talking about in this thread.

Sorry, but I must agree with Bruce on this one.. and agree to disagree I guess. I will continue breaking in my OS engines the way I've been doing it since I started out in this hobby and as I have been taught by someone that has been flying RC continuously for over 33 years now, and run it through two or three tanks switching back and forth from 4C to 2C.

I have a feeling that you are in the minority on this one, RC Pilet.

DS.

Well, I may go along with part of this.. running it in the air is not operating it at full throttle running somewhat lean. Flying it that way, with some throttle management, does go through the RPM range and does give it some stress at full throttle and will probably seat the piston to the sleeve just fine. But, as said previously, I will continue to break in my engines the way I've been doing it in the past. They all run just fine and I assume they will run just fine as long as I own them. I was taught how to break in, and set the needles by the club pro. He and his son are pretty much up there in the Pattern arena and seem to know what they are talking about.

I think it all boils down to personal choice and training. If that's the way you were trained and it works for you, well, that's just fine. I won't argue with that, and again, agree to disagree. Easy enough, right?

Nope. Anyone who knows what they're doing will agree with me. Your in the moniority and it's because your still doing it the way you did it 10yrs ago. The rest of us have adopted the newer methods and it works better.

These modern ABC engines are totally different and that requires a different break in procedure than what you were doing 10yrs ago or your friend was doing 30yrs ago.

All this bickering does nothing to help FlyByMe. I just want to HELP the guy. He needs to just read the Tapered Bore thread before he runs the engine. All this 4-stroking and whacking the needle up and down is BS and he needs to KNOW that.

You can disagree with me all you want. I don't care. I know how a tapered bore engine works and I'll continue to point the newbies to that Tapered Bore thread. I'll continue to contradict people who tell the newbies to 4-stroke their brand new ABC engines and run them overly rich during break in.

Not one of you can give me a reason why you shouldn't be doing your break in per the method described in the Tapered Bore thread. Can any of you tell me where or why that method is screwed up?

I can tell you why 4-stroking a new engine is screwed up. I gave you a VERY good explanation of how thew engine works and why it needs to heat up and why it's no good to run it overly rich.

Can any of you tell me why this is wrong: ?
Start it.
Rev it to full throttle immediately.
Remove the glow igniter.
Lean it to peak for split second.
Now immediately back it down (richen) about 1/2 --3/4 turn.
Let it run out a tank at wide open.

Now let it cool for about 15 minutes. Fuel it. Adjust the high speed needle to about 1/2 turn rich. It should be a little rich, but NOT 4-stroking. Check the low end needle and adjust it to idle for about 10--15 seconds before it loads up and needs to be revved to clean it out.

Now go fly it and lean it 1 click every 2nd or 3rd flight.

When you get through about a gallon of fuel, you'll be ready to tweak the low end perfectly and you should now have the high speed needle leaned out to within about 1/4 turn of peak RPM. It's broke in. Go fly it.

Rcpilet - your method will work just fine. May I suggest that you learn Japanese and convince the engineers at OS of their ignorance. I'm sure they will love to hear from you. You have such a soothing way of calling people idiots that don't agree with YOUR line of thinking. It will carry you far in life I'm sure.

Good day.