The1User

Hello everyone,

I have been flying for about 5 or 6 years and over that time I have always owned used planes and never had to do an "Engine Break-in"

I bought a Pulse XT 125 and after all the parts I could only afford the cheap Evolution 120NX
(everyone says it's an ok engine and pulls the Pulse 125 around nicely)

I spent 2 hours reading all the posts (back to like 2006) about Ringed Engine Break-in, There were a lot of fights and arguing

The manual is seems kind of vague (and goes against what some people here say)

I don't want to start another argument, can someone look at the text from the manual below and tell me if I should do the Engine Break-in the way stated in the manual?

THANKS !

Joe

TEXT FROM MANUAL:

Engine Break-in
Ringed engines need a different break-in procedure than a typical ABC-style piston and liner construction. The component that provides the compression seal is a spring steel ring that needs to fit itself to the minute scratches on the interior surface of the cylinder liner. With care in this process your ringed engine will last a very long time. If you ever notice that the power seems to have dropped on your EVO 1.20, a quick installation of a new ring and a new break-in period will restore your engine’s health to near-new condition.

1. Mount the engine on a test stand or in the airplane you intend to use the engine in. If there is cowling around the engine, it would be a good idea to do the break-in process with the cowl removed to allow adequate access to and cooling of the engine.

2. Fill the fuel tank with the fuel you intend to use (10–15% nitro).

3. Start the engine and leave it running rich, with the glow igniter attached if necessary.

4. Open the throttle wide open, and let the engine run at a rich ‘4-cycle’ (where the engine actually doesn’t fire each and every time. With experience you will be able judge this easily. For those new to nitro engines, you will hear a sharp increase in rpm and sound when the engine transitions from a ‘rich 4-cycle’ to a 2-cycle run). Let the engine run through the tank at this setting, or at least 10 minutes, then shut it down and let it cool completely.

5. Restart the engine, but this time to vary the needle settings, with brief periods of 2-cycle running alternated with longer periods of 4-cycle running, through the next tank of fuel for at least 10 minutes.

Note: A good way to judge the time limits for the 2-cycle and 4-cycle running periods is to touch the cylinder head with a free finger while adjusting the needle valve. When the engine is at a 2-cycle, you want to richen the mixture when you can no longer touch the side of the cylinder with your finger. Conversely, the engine has cooled enough when you can touch the cylinder comfortably.

6. Repeat Step 5 one more time and then the rest of the break-in can be accomplished in the air. Set your engine’s needle valves per the instruction manual. If anything, continue to err slightly on the rich side and your engine’s performance will continue to improve over the next gallon of fuel or so.

chocorrol

I would do what the manual says... if they made the engine, I bet they know what they are talking about, don't you think so?

Lnewqban

I see nothing wrong with the method.

Ringed engines require more time for proper break-in.

Check this link out:

http://www.mecoa.com/faq/breakin/breakin_ringed.htm

Gray Beard

My Feedback: (-1)

Each manufacture has a bit different way to break in an engine, they went to all the time and trouble to design the engine so they have broken in a few and know how they want it done. For two stroke engines I use SK designed by the engineers at Super Craft and made in China for them. The engineers came up with there way to break in the engine and what props to use. This is one of the only engines I know that have a different break in then the instructions that come with the engine.

Ed_Moorman

My Feedback: (1)

Your method sounds good to me.

SK ringed engines, like the 90, unlike virtually every other brand of ringed RC engines, have a tapered bore like an ABC engine. As such, they should never be run in a rich 4-cycle for extended periods of time. You need to alternate between lean and rich for cooling, but don't stay in a 4-cycle more than 10-15 seconds. My 2 SK 90s have been great engines, very reliable and easy to start. 15-6 prop is best.

dredhea

My Feedback: (13)

The published method sounds good. Be sure that you never let it get so hot that you can't touch it. At its hottest, you should still be able to hold your finger on it for several seconds (5-6), though it should be very uncomfortable to do so. You should NOT get blisters

cutaway

Treat it gently as directed. My little ringed ST G.34's performance kept improving visibly over the first two hours or so. I kept the first 20 minutes of running down to about 2 minute runs though, and ran a very oily 75/25 FAI mix for the first couple of hours. Now its very happy on 80/20 FAI and screams. At about 7 hours running time, I'm still on the factory ST plug.

Unless that Evo's compression ratio is very low, it should run fine on a cheap zero-nitro FAI mix.

downunder

The method in the manual sounds fairly good although it only totals to 30 minutes before flying. I like to give ringed engines an hour or so on the bench with a bit of just barely 2 stroking near the end of the hour. I've never found it necessary to keep the glow igniter on because they'll all run very rich, slow and cool without it. Ringed engines do take a long time to get fully run in as your manual suggests in the last sentence. I noticed a very gradual increase in performance with my ST G51 over a 15 hour period which is exactly what ST used to advertise with their ringed engines. I've just finished 75 minutes of bench running a ringed Enya 61 before starting to fly it but the ring itself has just begun to run in. The ring will be fully run in when all the machining marks have disappeared but it's more than capable of being flown before then. The seal just gets better and better. The Enya BTW uses a brass liner plated with Nikasil .

One thing I'd disagree about with the manual is their recommendation on fuel. You don't have to use whatever you're going to fly with, even zero nitro is perfectly OK, but I'd use a fuel with a fair bit of castor.

chocorrol

maybe they only mean that you don't have to use any special fuel to the break in process and they talk about 10 to 15% because that's what they recommend for normal usage.

ameyam

I have discovered during my experiments with a 75ax trying put various props (from 13x6 to 14x8) to keep it cool that you dont necessarily need nitro. I found that this engine ran the coolest at 0% nitro. That may be geographic though. They recommend to add nitro for colder countries to help retain operating heat and to keep the engine from deadsticking at idle and hence to get the engine to idle better

Ameyam

Gray Beard

My Feedback: (-1)

This is a file I sent Ameyam to help him understand what Nitro is doing during the burn. It's from a how to tune article. The use of nitro has been gone over a hundred times on RCU if anyone wants to do a search.

The1User

Thanks for all the info everyone,

So #3 "Start the engine and leave it running rich, with the glow igniter attached if necessary"

The motor comes from the factory with the high-speed needle adjustment closed all the way, any guess about how many turns out will do for starters?

Then run "sloppy" rich (what they call "4-cycle" rich) with the throttle at full for at least 10 minutes?

I know for you guys that have done this before this must seem easy but I want to do the best break-in I can

Thanks

Joe

Gray Beard

My Feedback: (-1)

Two turns out will usually start the engine rich but then you have to twist the needle where you want it. Everyone started out new so you aren't the first one to have these questions. There is also a glow engine forum you can go to and look things up.

CGRetired

My Feedback: (1)

When I started out, my instructor was the first one to start my engine. He started it, broke it in, and then we flew.

A short time after my solo, I had an OS 52 Surpass four stroke. Not a good engine for a beginner, however, I was game and decided to give it a try.

Well, the two turn trick got it started, and I followed the general rule of running it "blubberingly rich" for a minute or so, then richen it for a few seconds, then back to blubberingly rich. After a few tanks like that, it ran like a charm.

My point is that we all start somewhere.. and following the general "rules" concerning breaking in engines, will get you up and running in short order. Just listen to what the forum pro's, like Graybeard, Opjose, JohnBuckner, and others (I don't mean to exclude anyone, but those are the names that come to mind at 9:00PM EST and after a long tiring day) are telling you and you just can't go wrong.



CGr.

Gray Beard

My Feedback: (-1)

I'm sure Bax will have something to say about people like myself but I am one of the really bad ones when it comes to breaking in an engine. I do it with the SK line of engines but I'm a bit hit and miss with the other brands I use, OS and YS. Sometimes I do and sometimes I don't. When I first started flying RC I didn't bother at all and over time I sometimes do. I don't spend a lot of time worrying about it when I buy a new car, I just fire it up and drive. I do keep a close eye on my oil and water the first few thousand miles. I used to build VW engines for both street and sand drags. Street engines I did give the owner instructions for the first 500 miles but for off road use?? For a cheap {not so cheap} thrill go take a new engine to the dyno shop!! Be ready to throw away the pants you are wearing. Brand new engine, never fired up and put through a test that will scare the peewaddle out of you. When it's over you know everything there is to know about the engine but it's not for the faint of hart. I would rather be breaking in my glow engines while in the air then burning fuel on the ground. I do a lot of loops and stall turns the first few flights, gets them hot on the way up and cools them on the way down. I just haven't ever noticed a nickles worth of difference between an engine I have broken in on the graound or one I broke in while flying. I do run new engines a bit on the fat side but not for long. I used to work in a small engine repair shop and sold brush cutters and chain saws, no one ever wastes time breaking in one of those, just fire it up and go cut a couple of cords. Perhaps someone like Bax could give a more detailed reason for the break in that the instructions say to do. Is it really something that has to be done?? I have built engines that were on the stand one day and in a car and on a race track the next day so I do question it.

CGRetired

My Feedback: (1)

I was at the field one day and one guy was "breaking in" his engine.

He babied it to the point where he would not allow the engine RPM to go above about 4000 RPM (using a Tach) for at least two tanks. He was watching the RPM and the throttle setting to the point where it was really difficult to watch him do it. My reasoning there was that I had recently ran an engine in on my front lawn (the plane was tethered to the ground and I ran the engine up through at least two tanks of fuel.. maybe three). My technique was full throttle with blubbering rich HS needle setting, with occasional excursions to lean for about 10 to 20 seconds, followed by blubbering rich settings.

So far, I've not had an engine that gave me any problems at all. That included both an OS four stroke and numerous OS two strokes.

The guy that babied his engine had lots of problems getting it tuned properly and getting it to perform. His excuse was that it took several gallons of fuel to get it to run right. Mine ran right from the very beginning.. in fact, I would feel comfortable flying it right out of the box with the needle set somewhat rich.... quite a bit rich, but flyable...I'm sure you know what I mean.

Now, these were mainly OS AX series engines, with a couple of FX and one or two SF engines, and one Super Tigre 75's that always ran just fine, but leaked fuel all the time. I did have a few Evolutions, but those were a disaster and I gave them away. I could not get them to run well enough to fly no matter what I did.

CGr.

Gray Beard

My Feedback: (-1)

Ed Moorman wrote an article on the SK and due to it's design I follow Ed's break in to the letter. If you didn't know I'm a big fan of Ed and use his how to stunt flying lessons he wrote in RCR. Other then the SK I'm pretty bad about breaking in. When I first started RC I was using the OS LA, SF and FX engines. Breaking in was never a big deal with the guys at the field either, just start them up, run them until they would hold a tune and go fly. By the end of the day all was good. These are not ringed engines though. I never saw anyone giving a lot of thought to break in until the AX model came out?? Other then the ring seating and a little bit of valve and bearing wear in I just can't understand all the worry about breaking in a four stroke or ringed engine. Some engines like Moki can suck up a lot of fuel before the ring seats and the engine comes alive. That's a lot of ground work. That's why I say, maybe Bax can enlighten us all on break in. Bill sees these engines day in and day out, understands everything about them so I figure he is the person to be asking why. When I have an OS problem he is my go to guy.

CGRetired

My Feedback: (1)

That's good advice, Gene. As I said, I fly mainly OS AX's so I havn't really had a problem like that. I buy what the LHS had in stock, which was OS. Now that they have gone the way of the economy, I am an internet ordering type person so I get what I need regardless of the manufacturer.. with some guidelines... I take advice posted here by such experienced folks like you, Gene, to get me into what I need, so I thank you for that.

CGr.

ameyam

CGR, thanks for getting that out of my head. I have 2 engines -a 55ax and a 75ax, from my trainee days that have recently given me a lot of problems. I was told that this was becuase, like you, my instructor didnt run these in properly on the ground but rather, he set them rich and flew with them directly (no nose up flights though). Now that you have mentioned that this is also as less desibrble but acceptable practice for 2c engines, it will put mind to rest that I did not do wrong in not objecting to his impatience with the engines.

For the record, we too run the engines very rich and full throttle with intermediate leaning for 10-20 seconds like you said and I will ensure we do this with all further 2c engines

Ameyam

RC_Air

Running a new engine rich only has one purpose, to ensure there is lubrication, In a ringed engine the edges of the rings must wear down and at the same time the edges of the rings bite into peaks of the honed cylinder walls.

An engine doesn't have to be run to be broken in! The only thing that's going on in the break in process is bearing surfaces are getting worn so they have less friction - and cylinder walls which need microscopic peaks and valleys for the entire LIFE of the engine need to have a place for oil to stay on the side of the cylinder wall to lubricate the ring going up and down.

And yeah, its the same on a VW lol get a clue, F1 race car or our model engines, Don't think you have to fire and run an engine to "break it in" - that's just how we do it - but the "breaking in" process has always been about "seating" rings - and seating rings is NOTHINGMOREthan the edges of the rings cutting into the peaks of the honed surface of the cylinder wall, leaving the valleys to hold the oil. There's nothing magical about it - and these days with machining advancements an engine is virtually broken in from the factory.

Just keep the engine blubbering rich allows the edges of the ring to wear down the microscopic peaks of the honed cylinders.

And by the way, in my investigation OS engines over the past 20 years have the worst tolerences for sloppy piston / cylinder tolerences. It would be interesting to hear if other people have found this to be true.

CGRetired

My Feedback: (1)

I also run them slightly rich even after break-in. I was taught to use the "pinch test" to set the high speed fuel mixture, and to leave it at that slightly rich setting. Some claim that if you can't see smoke when flying it's not rich enough. That may be, I don't know because I always set it rich enough that I will see smoke when flying. I've not set it to lean, at least not that I can recall.

The most difficult time in a flight is when headed straight up. The fuel has to travel up into the engine and tends to be somewhat lean because of that. So, that's one main reason to run them somewhat rich.

CGr.

ameyam

Since I do a bit of 3D, I have the maximum problems with the vertical thing. Couple of weeks back, with the engine set rich (quarter turn), I kept losing power in the vertical and finally deadsticked. After I landed I noticed that the 75ax I was using was overheating. I tried various props from 13x6 to 14x8 and it overheated in all of them to the extent that there was no compression when hot and there was black oil in the exhaust. Finally I shifted from 10% nitro fuel to plain synthetic and since then it has stopped overheating. Today, I tried hovering again, this time with a 15x4 prop. Now I I need to resolve is the amount of throws, because the engine performs quite well.

For the vertical, I get someone to hold the airplane vertical to set the HSN and then set it. This setting is almost always richer in the horizontal than the horizontal tuning and ensures I dont deadstick in the hover.

Anyway, we are digressing from the OP's question

Ameyam

Gray Beard

My Feedback: (-1)

I have heard that smoke trail crap for years, you tune the engine, not the smoke trail. With some of the fuels we have today if you tune the engine correctly there is almost no smoke trail to be seen. Example: I have an Extra with a YS 1.20, I was using brand XXX fuel and it only contained 16% blended oil, no smoke trail. One fellow at out field was telling me how lean I was running because I had almost no smoke trail. I decided 16% blended oil wasn't enough so I added two ounces of Klotz blended oil. Never touched the engine needles but now it has so much smoke it looks like it is on fire. No RPM changes at all, that Klotz blend has 20% castor in the mix, wonder where the smoke trail came from?? Other then the couple of two stroke SKs all I use are YS and a couple of OS four strokes. I was running 300 RPM rich and discovered my engines wanted to be run at 500 rpm rich this time of year. 200 rpm difference is all it took to smooth things out.

CGRetired

My Feedback: (1)

Yeah, Gene.. I was sort of hinting at that, meaning it didn't matter what the smoke trail looks like as long as the mixture is set right.. I should have explained my reasoning.

It varies from day to day how the engine tunes up, and, as you said, there are times when I can't see the smoke, but the engine is running just fine.

CGr.

Gray Beard

My Feedback: (-1)

I saw the hint but felt it should be hammered home. Not too many years ago our fuel was pretty much just Castor oil and the smoke trail thing was true. It's a hold over from bygone days. Bygone, hope that's a word!! Another thing that has changed and some of the peanut gallery hasn't grasped is the anti foaming agents put in the fuel, it really works well and we no longer have to pack our fuel tanks in 6 inches of foam to keep the fuel from foaming up with vibration. The best video I have seen showing this was one from Germany. They were showing how fuel moved around during flight. A clear fuel tank was mounted on the outside of the plane with a wing mounted camera, the plane was flown through a complete series of stunts, it was a split screen so you could see what the plane was doing. Not only was it an eye opener as to how the fuel moved around, it showed how fuel no longer foams up. The tank was hard mounted. I had the thread in my favorites but it is no longer active. I showed it to people just so they could see the fuel moving to different locations through out the flight. Wish the site was still working!!