OK guys.....

What is the deal with breaking in a 46AX? I am getting ready to get mine going, and I remember seeing all these posts indicating that the instructions for breaking in the engine, that were included by OS are "wrong" and that I dont want to do any "four cycling", and that OS itself has corrected its stance on this issue.

I cant find the original conversation on this, in RCUniverse.... Who can point me in the right direction?


-Tom

I'm sure other will have a rather differant view from me, but i've never been big on spending hours mucking about running an engine in [:'(]

I Run the engine nice and rich, normally 4 stroking for a while (something like 5 mins) at idle, carefully lean it off a little so it's sounds a little crisper and finish a tank

Tank 2, still very rich and take flight, just being careful not to load up the engine a whole lot

Tank 3 lean it off some more

Tank 4, power tune


Never failed yet, do note however, this only really applies to non ringed engines

Thats what I need....simplicity.

I break my 2 strokes in by the "2 minute plan".

Start the engine, peak it out and then back off 1/8 turn.

Let run wide open for 2 minutes, then shut down and let the engine completely cool off.

Run out your first tank this way.

If the engine was very tight to begin with, I would run a second tank this way also, other wise go fly it.

Back off on the needle valve 3/16 - 1/4 turn for the first 30 minutes of flying time, then run it as you usually would.

This works very well with ABC, ABN, etc. DO NOT USE THIS PLAN IF IT IS A RINGED ENGINE, it will damage the engine.

I just rev it up to full on the ground and go rich, lean, rich, lean for about 1/4 of a tank...then I run 'er rich in flight and fly in the pattern at 1/2 throttle...works good. (BTW, I have the OS 46 AX as well)

You may want to check the OS website under the FAQ section. You do not want to run this engine 4 cycling rich, I broke mine in always in two cycle for 1 tank at a rich setting. Put it on the plane and fly, just keep it on the slightly rich side for a couple flights then start to peak it out. These run well out of the box and an elaborate break in is not really required. I've got a gallon through it now with no problems.

Listen to Camss69 & Campy. Rich is for ringed engines & steel-sleeved engines. The "pinch" fit at the top of the cyl in an ABC/ABN engine will be degraded by running the engine too rich during break-in. Run it just into 2-stroke mode, at full throttle in ~ 3 min bursts. Then cool & repeat until you have gone through a couple of tankfulls

Follow the OS directions:

1. One minute at full throttles with needle valve 1.5 to 2 turns from seated position.

2. 2-cycle for 10 seconds

3. 4-cycle for 10 seconds

4. Continue alternating 2 & 3 until you empty the tank.

5. Start flying on 2-cycle setting.

6. After each flight, lean engine a couple of clicks.

7. The final position is the needle valve set rich from maximum RPM. This is called the optimum setting and is around 15-30 degrees from maximum RPM (leanest setting).

Your engine will now last forever! And finally, how can the OS instructions be wrong? What are you people smoking? No wonder human progress has been so slow!

Ciao,

Eagle Al[&o]

how come my engine is running backwards? I started it and is going in the wrong direction and the prop is on right..... i tried switching the starter around and then it wont start. It is a bran new O.S 46

This is not what the OS webpage says to do, and also not what is recommended by the OS rep on RCU....

Your starter should spin clockwise if you look at the rubber drive end and the engine should to anti-clockwise if you look at it from the spinner end

just incase

You're starting it by hand, or with a chicken stick, aren't you? This happens sometimes. Most of the times if you open the throttle up a bit and then close it, the engine will magically reverse itself. If this doesn't work, try some reverse psychology, flip it the opposite way. No, I'm not crazy (at least on this topic ), this really works.

[Your engine will now last forever!]


And whoever may still be around at the end of time will be responsable for placing a post to that effect. I will be waiting.

jess

I have just recently bought two OS 46 AX engines. I broke the one in as per the instructions and it seems just fine. I must admit that I am new at this , have much to learn, and this engine has not been in the air much, and with an instructor with me at that. I am working at breaking in the second engine now. The posts here have me some what confussed. I have tryed to understand these terms I hear about. ABC, ABN, ABL, etc. Someone has said that the instructions for breaking in the OS 46AX are not correct and OS has corrected that as per their web page. I went to the web page and what I find is instructions on breaking in the OS 40FX which is suppose to be an ABN engine. The OS 46AX engine is decribed as an ABL engine (advanced bimetric liner) and I could not find where it said to break in the OS 46AX any different that what the instruction manual says. Can anyone clear this up for me. Learning how to fly is stressful enough for me. Adding on that I might be breaking the engine in wrong is stress on top of stress. I appreciate any help you might have.

Poppy2

In the case of the OS Max .46 AX, ABL is ABN. The difference is that a copper layer has been laid down on the brass liner before the nickel finish coat. That copper layer assists the nickel in bonding to the brass liner core & is intended to eliminate the peeling liner syndrome common to the SF (ABN, not ringed), FP, FX & LA series of OS engines. Break-in should be the same as for the FX ABN engines (& the same for ABC/ABN engines from any manufacturer).

Numerous well-regarded model engine engineers & experts determined quite a few years ago that a rich break-in actually damages the tight upper cylinder fit of modern ABC/ABN engines (and ABL). You may follow the OS directions if you wish -- it is your engine, but many well experienced ABC engine users no longer use that rich mixture method.

Currently, the best break-in results are considered to come from using fuel with a nitro content similar to that of the intended end use, & with at least some of the lubricant being castor oil, & with total lubricant content not less than 18%. The engines are run at full throttle, at a rich 2-stroke (just barely past the 2/4 transition) for a period of 2-3 min, then they are shut down and cooled off completely. The cycle is repeated until total run time is about 30 min. The engines are then leaned out to peak rpm & observed for an rpm-drop. If they won't hold peak RPM, then additional break-in running is added.

Following break-in, for regular use the engines should be adjusted for peak RPM, then richened up until full-throttle engine speed drops by 300-400 revs. You can do this by ear -- peak the engine then richen the mixture until the revs just start to drop.

The proper method of breaking in this kind of engine is still the subject of great debate (and experimentation by some to see if the method really matters). The consensus of most experts is that they should be broken in rich, but not sloppy rich. Here's a thread that has lengthy information on breaking in this kind of engine: http://www.rcuniverse.com/forum/fb.asp?m=1850473

Chuck, I must say that you did an absolutely wonderful job of condensing volumes of information into your reply. Nothing more need be said. Perhaps your reply will, as it should suffice

jess

I want to thank both Britbrat and Piper Chuch for taking the time to reply to my question. You have made it as clear as it can be. As Jessiej said in his reply, you have put volumes of information in a nut shell. Your help is deeply appreciated.

Poppy2

Awwww, shucks, twas nothing.

Thanks & have fun.

OK guys. I have some concise feelings, being the guy who started this whole thread of conversation:

1) Using OS's recommendations, is no different than using one of the many possible opinions that have been posed on this thread. I had thought that maybe there was a corrective statement out there made by OS on their website about breaking the engine in....or maybe somebody could tell me..."Everyone in the hobby does it this way.". I found that really, there are just alot of competing opinions.

2) If I use OS's recommendations, at least I can tell OS that I broke it in, per spec, if I have a warranty issue

I am sure everyone could agree with both my points.

-Tom

Tom,

I have done quite a few of the OS46AX engines. I have always done them per the manual for the exact same reason you mentioned in regards to the warranty claim if needed.

Now, I personally have never had a problem with the engines and even though I no longer have any of them, I do get to see them run on a weekly basis as I sold everyone of them along with the plane that they were mounted in to other club members.

Most all of them are now over 200 flights using the exact same fuel I broke them in on (Byron 15/20 Castor/Syn blend) and all of them are on the same glow plug as they started life with as far as I know.

The only adjustments they ever needed after getting then properly tuned on both the low speed and high speed needles was the odd click here and there for the high speed which was more weather dependent than anything else.

I every case, if the engine was cold, open the throttle, 3 or 4 flips of the prop with my finger over the carb to get fuel up, close the throttle to normal idle attach the glow driver and bump it with the starter and off she went. If the engine was recently run, no priming, just attach the glow driver, hit it will the starter.

I have now used the same breakin method for my OS160FX's and they have all responded the same way with the big difference being I do not use a starter. I prime it, attach the glow driver and bump the spinner clockwise against compression which then kicks the engine the other way (counterclockwise) and off we go. On occasion I bump it too hard and it runs backwards but I just close the throttle completely and try again.

Maybe I was just really lucky on all of them.

I will probably cut over to the pure synthetic fuel, but am thinking I will run the castor for awhile, during break in...and maybe the first 10 flights or so. I have heard the green stuff is "too good" for break-in, and doesnt allow the engine to properly run-in.

Oh well..gotta keep perspective. this is a model airplane engine, not the space shuttle. LOL

[I am sure everyone could agree with both my points.]

The only thing I am absolutely sure of is that everyone on this forum can agree on nothing.

jess

I am by no means an expert, but I do have a lot of high performance engines around the house (my snowmobile is over 165hp now) a am quite a motor head and study this stuff. I see a lot of people using the factory recommended method for breaking in this engine, and others saying that it's not a good idea, but I didn't see anyone say why. The reason is because the cylinder is tapered at the top. As the engine builds heat it expands so the cylinder is nearly cylindrical when it's running, but binds up to some degree when it's cold. If you don't get enough heat in this engine then the tolerances are tight and you run the risk of running the engine at high rpms with out proper piston bore clearances.

Because of these reasons if you run it so rich that is sounds like a 4 cycle, then you are really cooling down the piston which causes it to get pretty tight.

What others posted about running on the rich side, with a 2 cycle sound for 2-3 minutes heat cycling will cause the machined surfaces to mate while keeping good tolerances.

Just my $.02.....