aec12

I just bought a new TT Pro 46 to put on my new Goldberg Tiger 2 airplane. I was wondering if someone could tell me the best break in procedure for this engine. The manual doesn't really give much detail on the break in. I am fairly new in the hobby and I don't want to ruin my new engine because of lack of experience.

Thanks for the help,
Allen

Sport_Pilot

As I recall I broke mine exactly as the manual stated. It's not much detail, but really all you need.

aec12

Thanks for the reply Sport Pilot.

Allen

elmshoot

My Feedback: (6)

A few tanks through the engine on the ground then fat 2 cycle and do cuban eights since it cycles the engine load and you don't spend a lot of time making noise in the pits. About 3-5 minutes of flying then land and let the engine cool to ambiant temp about 15 minutes fuel up and do that again. slowly start leaning the NV after about 10 flights like that you should have a good running well broken in engine. Dirt and lean runs are the way to wear out you engine early.
Sparky

aec12

Thanks for the info Sparky. So you are saying I need to run about 10 tanks of fuel at a very rich setting before leaning it out to optimal setting?

Allen

Sport_Pilot

aec12,
You will find that people tend to come up with some unnecessarily complicated break in schemes. Just don't get it too lean run a couple or three tanks on the ground then fly it slightly richer than normal.

aec12

Thanks Sport Pilot,

One reason I posted this question is that I wondered if the break in procedure wasn't being made more complicated than was really necessary. Maybe that is why the manual for this particular engine isn't very detailed concerning break in.

I am going to try your method. Does this sound right? A couple of tanks on the ground at a very rich setting. Lean it out a bit and put it in the air. Then, lean it out a click at a time after each flight until optimal setting is reached. Please let me know.

Thanks,
Allen

Sport_Pilot

Without looking at the manual in a few years, I'd say that sounds about right. Some say the short runs are to heat cycle the engine. The only use I can see is that it helps to prevent from overheating the engine. Which could be helpfull if you are not sure it is rich or lean.

LearjetMech

I took mine out of the box, put it on ran it through a couple of heat cycles on the ground over a couple of days (maybe a tank of gas). Put it in the air after that. Haven't had any problems with it at all since. Plan on doing the same with my Pro .61 I have in the box right now. Just keep it a hair fat and vary the load.

Gene Chernosky

My Feedback: (182)

This break-in method will make them run correctly and last a LONG time. This was given to me by the late, great, George Aldrich...he forgot more about engines than most of us will ever know!

Set-up the engine on test bench with a 10x6 prop* on it. Get it running and bring it to a lean run ASAP and then shut it down...make this run as short as possible! Let it completely cool down and install a 9x6 prop* on it. Start it and set the top speed to 16.5K RPM and hold it there for 2-3 minutes...use a tach to do this! Shut it down and let it cool a LONG time. Then install a 11x5 prop* on it and run it through three 8 oz tankfuls at full throttle set just leaner than the rich/lean break letting it completely cool in between tankfuls. Then put it on a plane and go have some fun. *APC

I have done this on MANY TT PRO .46's and have ALWAYS had them end up running perfectly. This method applies to most any .46 sized ABC engine, too...and would apply to any size ABC engine after adjusting prop sizes accordingly.

If you deem this method complicated...hmmm...you're pretty ignorant.

piper_chuck

My Feedback: (12)

I thought I read something recently warning against running ABC engines at a very rich setting. Something about not allowing the liner to expand enough, resulting in excessive wear between the piston and liner. The method Gene just posted sounds like it makes alot of sense for ABC engines.

aec12

Thanks for the info, Gene and Learjet,

Very, very helpful information for me. I think I am getting the idea on what a proper break in consists of.

Thanks,
Allen

Sport_Pilot

Genes method is faster, but not necessarily better. Depends if you intend to watch it, time it, and are experienced enough to know if it is overheating before it is too late. The warning you are thinking of is running in a rich four cycle, the theory is that the cylinder will not heat up enough and the piston can seize and throw a rod. I have even seen engines broken in running in a rich four cycle. You still have to remove material from the piston, as long as you lean it up enough before too much material is taken off you will be fine.

AdrianM

I like the way Dub Jett recommends:

For break in pick a prop 1" smaller in diameter than what you intend to use. I love the APC 11x5 on my 46 engines so I run a 10x5 for break in. Most 46's max out at ~13,000 with the 11x5 so start really rich, run the engine wide open with the 10x5 and lean the needle so it maxes out at 13,000. This ensures a rich, hot, high RPM, low load break in which is what ABC engines need.

Run the engine like this for 5 minutes. Let it cool to ambient temp then do 4-10 minute runs with time to let the engine cool to ambient temp between runs. The cooling lets the engine heat cycle.

Now you can put on the 11x5 and lean out the high needle. I lean it up to max then richen down 500 rpm on a new engine. After a gallon of fuel I set it to 200 below max unless its a fast plane with a small prop that unloads a lot.

Now you can set the low needle.

Close the carb to the lowest reliable idle. Count to 10 slowly then rip it wide open. Does it bog? If so its too rich on the low end. Close the low needle 1/8th of a turn. Run the engine wide open to clear out the crank case (thats important). Set the carb for tho lowest steady idle count to 10 and rip it open again. Repeat the process and keep leaning until the engine quits when you snap the throttle open. Richen the low needle 1/4 turn and repeat the process. It should be perfect.

All my 2 strokes last forever, run VERY strong and I will put the throttle response of my engines against any 4 stroke anytime!

Gene Chernosky

My Feedback: (182)

Excuse me...but it is not MY method. This method was passed on to me by en engine guru. Mr. Aldrich was an EXPERT with model engines. He was more knowledgable than virtually anyone when he was alive.

A VERY close second IMO would be Dubb Jett. The method AdrianM describes that is Dubb's is yet another way to 'skin the cat' when it comes to breaking in an ABC engine.

The most basic principle of either is to NOT run the engine rich enough so as to not let the sleeve expand. There MUST be some heat developed during break-in of an ABC engine or the 'pinch' can easily be damaged leaving the piston/sleeve to wear out FAR before it would if it was broke in properly.

Cyclic Hardover

My Feedback: (3)

Just run it a tad rich and fly it, Everything else is a waste of time. The engine does not know if it's attach to a bench or on a plane. Run a tank or so through it, dial it in and fly it.

Hey "MEAN GENE," How 've you been?

AdrianM

I just like the peace of mind that its perfect when I put it in the plane. It will idle all day from the first flight on and I only have dead sticks when I have too much fun and run out of fuel.

GRANT ED

Everytime someone ask's how do I run in engine brand abc model xyz. There are always a bunch of different techniques on how to do it. Some are long and al ot are not necessary. Now before anyone says who am I to say what is necessary and what is not, I am not the one's saying this, the engine manufactures are. I have 2 TT 46's and have run them in as close as I can to what the manual says. That is run it a bit rich for the first few tanks and then tune normally. Easy as that. Both my engines run perfectly.
I think a lot of these long winded run in techniques are based on older engine designs. Even in my OS 50 heli engine manual it states that 'due to modern machining techniques long run in procedures are not needed and that all that is required is to run your engine slightly rich for the first few tanks'. This is a ringed engine also. When I bought this engine I was told a hundred different ways to run it in. I eventually decided to follow the engine manufactures instruction. So far its another perfect engine.
I think these techniques had their time and were valid, but with modern engines are not needed. People will say I'm wrong but Thundertiger, OS and Supertiger (probably more but these are the only engines I own) say I'm right and I'm pretty sure these guys know a thing or two about model engines.

Sport_Pilot

Then you should know that Mr. Aldrich did not tout this as a better way. Rather a way to get into the air faster. In fact he promoted a similar method while flying a control line plane. After this was done the engine may be run in a full four stroke.

Are the engineers at OS and TT more or less an expert? I submit they are the same or perhaps more. Not only that they know how their engine's are built. Jett engines are built for racing, but may be used for sport, because of that they are built with a lot of taper and a large interference fit, thus a lot of pinch at the top. Most OS engines are built for sport and quick break in, because of that they do not have as large of an interference fit, thus not as much pinch. With a large pinch you can possibly seize the piston with a full four cycle break in , without a large pinch it is not likely. Because of this Jett recommends that you avoid a four cycle run during break in, OS recommends to break it in a full four cycle. Well after break in both engines will have little or no pinch and run just fine.

AdrianM

I work with and know a lot of engineers. They are people just like you and me. Some are brilliant and some do an adequate job but flat out have no hands on understanding of what they are designing.

If anyone tells you to break in an ABC engine buy letting it 4 cycle they are stupid (even if they have a Masters in ME from MIT). The fact that a sport engine like a TT or OS has less pinch than a Nelson or Jett when new tells me I have to be twice as careful when breaking it in as I have a lot less margin for error before the piston and sleeve are ruined and I lose compression seal.

There are 4 keys to breaking in an ABC engine;

1. Heat - You need heat to establish the proper running tolerance between the piston and sleeve. Too cold and both items wear prematurely so that when you do lean it out and the parts expand you get a reduction in compression seal and a reduction in performance.

2. Oil - Run it rich but not 4 cycling. Jett's method of running a smaller prop as the same RPM as the correct prop by limiting RPM with the mixture ensures that there will be plenty of oil slinging around inside the engine

3. Low load - The small prop keeps the engine load low to reduce early wear and keeps the revs up.

4. High RPM - The engine will break in better if it is run at the operating RPM. High RPM ensures correct timing of combustion and inertial forces inside the engine