dhyde79

ok, the set of instructions I found over on RC Driver's site say to do 5 runs @ 3 minutes at temp, then letting it cool at BDC, then afterwards to do 3 runs @ 5 minutes letting it cool between....and then the directions are over......is it seriously telling me that 30 minutes of run time (minus cool down time) is adequate for break in? what's the rest of the break in that I'm missing.....

comparitively, the idle 2 run 2 took me almost 2 1/2-3 hrs, how can it be that break in using a method that (seems) to be more brutal to the motor and takes a fraction of the time?

Dave33

My Feedback: (2)

Use this tried and true method.
http://www.rbmods.net/enginetempering.php

MrSavage

^Agreed. The best method. It doesn't take long to break the motor in because if you use heat cycling, the motor gets up to much higher temps than using the sloppy rich idling method.

dhyde79

ok, so it's run it in cycles for the first couple rounds then run it gently through its first gallon?

Dave33

My Feedback: (2)

You need to read the instructions.
From the very 1st time you start your engine, plop the car on the ground & begin running it in a parking lot in 2-3 minute intervals, tuned only *slightly rich* getting the temps up in the 200F range on a normal day. Every 2-3 minutes, shut the engine down & let it cool completely with the piston at BDC, and then fire it back up; continue this cycle until you've run 15 min or so, and then bump up to 3-4 minute intervals. Vary the RPM and don't be afraid to get the temps in the 200's. What you want is heat cycling of the components without the incredible stress that comes with breaking an engine in when it's overly rich & cold. After cycling the engine in this manner for about 20-25 total minutes, it'll be ready for the track and race tuning.
3 minute run times for total of 15 minutes = running it 5 times
4 minute run times for another 10-15 mnutes = running it 4 times

rican25

I did the idle-in engine break in method slowly climbing the temps over 5-6 tanks and my Savage runs like a raped ape. However after reading the RB Mods method, that way just makes much more sense..... now I have run my Hyper in the same way and it seems ok but as for my next engine I will go the RB way. wish I knew about this sooner.

ShoestringRacer

Idling an engine, or letting it run slow during break-in, and 1/4, ½ throttle is all incorrect. You want WOT (wide open throttle) after it warms up. YES WOT, even when it is brand new. Although you want it on the rich side at this early stage. WOT is in order to bring it up to the temperature and fit that the sleeve was designed to run at. Anything less and you are just leading your engine’s piston and sleeve to an early death.

Yes, running at WOT slightly rich, but not 4 stroking rich is the proper way to do it. The following explains the proper way and WHY it is the proper way. Here is some further explanation I wrote a while ago for newbie nitro guys that were still doing that incorrect idling method:

As for break-in, there is a whole lot of misunderstanding about this and basic engine operation. I have read and studied a lot of information on this and also by Dave Gierke who writes in RCCA and Model Airplane News (also by AirAge) about RC airplane and buggy nitro engines and he's an expert. As well as Paris Racing, Stephen Bess, Clarance Lee, etc, in the research I have done over the last few years. It will take some time to convince yourself to bring a new engine to WOT but when you start to understand it and why it is correct, you will realize just how many people are completely breaking-in the engine totally incorrectly.


It’s important to learn the theory about how these engines run (2 stroke ABC, ABN, AAC - we are not talking about nitro ringed engines here which are different and therefore broken-in differently), and how to break-in, especially because I see WAY TOO MANY people using the wrong procedure of idling many tanks of fuel through the engine or running it very slowly during break-in. That is unnecessary and damaging which I will explain. Although we use the term “break-in”, by its word alone it is misleading because people wrongly assume it means to slowly and gradually bring an engine to tune by idling tanks of fuel but you will see why this is incorrect and unnecessarily wastes fuel too! Please be patient and read further to understand.

These engines use a sleeve around the piston to make the seal (piston doesn't have a ring) and it operates properly only with sufficient heat so that the sleeve can expand to its designed operating size and fit. (these engines are also referred to as “tapered bore” which implies their lack of a piston ring to seal the combustion chamber) All engines will be tight - that’s what people call “pinch”, especially when new, so on the initial runs, you want to have it get up to temp, so it can run how it is was designed to. By the engine getting hot the sleeve expands to the size it was made to run around the piston - properly sealing the combustion chamber for operation. When it is not running it is contracted more and the pinch will be more noticeable (the engine really shouldn’t be turned over without the purpose of starting it to prevent excess piston/sleeve wear). The pinch is what allows the cylinder to have compression because there is no ring on the piston to seal the combustion chamber.

By idling tanks and tanks through, or running overly rich and cool, the sleeve just wears MORE against the piston because it is not hot enough to expand to its operating size. Idling is cool operation, cool means the sleeve doesn’t expand, if the sleeve doesn’t expand, the piston just grinds away against it, destroying the ‘pinch’ which wont allow any compression. Even 1/4 or ½ throttle wont generate enough heat to prevent excess wear and/or help the break-in process. And by doing that you are prematurely wearing out and ruining your engine. The piston/sleeve is designed to operate at running temps. Not letting this happen by running cool and rich on the bench leads to premature wear. By idling away tanks of fuel I GUARANTEE you are doing more harm than good. As long as the engine is warmed up first, you don’t have to drag out bringing it up to temp when it is brand new. It wont hurt or damage the working parts. These engines are very simple 2 stroke machines. They do not have extensive moving parts such as valves, cams, lifters, springs, etc. or even piston rings (like 4 strokers) so all this extra gentle, overly rich, cool operation is completely unnecessary (and worse it’s harmful and will decrease the piston/sleeve life).

(in fact back when these ringless, tapered bore engines were first developed and used in airplanes with control lines attached, they didn’t even have carburetors, they were fixed at permanent WOT; in fact these engines are ideally suited to WOT operation all the time. Throttling them only lets the temp decrease and lets the sleeve contract, but the ideal condition for an ABC, ABN, or AAC tapered bore engine is the engine running at WOT operation.)

HOWEVER, the sleeve around the piston can be a delicate thing to maintain and it is not forgiving of improper treatment. The break-in is the most critical time when the most damage can be done by improper operation. And improper treatment of a piston and sleeve by running it at a temp it is not designed for is damaging. (either too cold or too hot, both are just as detrimental) Most often this is done by running it too rich which makes it too cold because the rich mixture doesn't generate enough combustion heat for proper sleeve expansion. Just as damaging can be an excessively lean run. If it is run overly lean for any length of time it will destroy the sleeve. (that is why fuels with castor oil as part of the lube mix are very good because they better tolerate the too high heat of a very lean run and will help to save the sleeve if it is not run too lean for too long. Avoiding an overly lean run is essential when you know enough enough about engine tuning to avoid it. Racers typically run very lean to get the most performance but their piston/sleeve needs more frequent replacement as well)

Running a 2 stroke engine slow and rich makes it '4 stroke' which means it fires every other revolution, and that generates even less heat. ‘4 stroking’ is indicated by that ‘burbling’ or stuttering, hesitant sound instead of the crisp clean ‘whine’ when it is running 2 stroke as designed. It causes damage and wastes fuel as well! Using a fan is absolutely not necessary on it. Most important is to 'heat cycle' the engine about 5 to 10 times to relieve the parts of manufacturing stresses. The heating to running temp and the cooling is what relieves the metals which is what the break-in really is. HEAT CYCLING REALLY IS WHAT BREAK IN IS ALL ABOUT. (I even think break-in should be called “Initial Heat Cycling” instead so that people understand what and why they are doing it.)

But heat cycling doesn’t mean 1/4 throttle runs or bench running with the tires spinning which doesn’t allow a load. (it is much easier to break-in a car motor on an engine stand with a properly sized propellor but doing it in the car is ok if done properly)

You run the engine in the car for 2 - 3 minutes at a time going to full throttle on straight line passes (yes, WOT, don’t baby it), ideally on a smooth paved level surface, after briefly warming up of course, and then shut down and repeat after the engine has fully cooled. Let it cool down completely. Heat cycling is the name of the game. You want it to come up to temp for a brief time - 2 to 3 minutes, and cool down and repeat. VERY IMPORTANT: after shutting down, adjust the flywheel so that the piston is at BDC (bottom dead center) so that it does not get stuck in the contracting/cooling sleeve, as can often happen. (If the piston should accidentally get stuck in the sleeve, heat the cylinder with a heat gun or hair dryer which will expand the sleeve to free the piston from the sleeve.)

During these initial runs YOU WANT the temps to be at least 200 F but not above about 250 F. But don’t get carried away and overly focused with temp gun readings - people often times chase their tails with temp guns because of variables of readings and also it’s really not that necessary. As long as you see a good amount of blue smoke from the pipe you know you are running rich enough. After break-in, running temps above about 250F is fine. (In fact nitro engines perform best when run 250-300. Below those temps they are less efficient and less powerful and more wear is occurring to the sleeve and piston because the sleeve is not fully expanded. However, going by the mixture is more important than trying to measure temp, etc. which you may wind up doing inconsistently. The mixture setting on the High Speed Needle (HSN) is critical in the first runs. It should be a rich and not lean setting. However it should not be so rich that it 4 strokes. - 4 stroke operation means the excess fuel causes the glow plug to ignite the mixture every other stroke and is defined by a very burbling sound when running. (Yes, two stroke glow ignition engines can “4 stroke” in the combustion cycle contrary to what you might think. It is very easy to hear this when you have the engine on a stand and can hear immediate changes to mixture adjustments) (the stock instruction book settings are usually quite rich and may need leaning on the first runs from book settings)

Also, to start a brand new engine it is sometimes worthwhile to heat the engine with a heat gun or hair dryer if it has a very tight piston/sleeve fit and you are having trouble turning it over to start it up. This will expand the sleeve some, and when you turn it over the piston will not excessively rub, or even get stuck in the sleeve (as sometimes can happen). Preheating really works well. You do want to run it on the rich side, but you want it to come up to temp also, just not more than 2-3 minutes in beginning runs, in order to keeps temps around 230 - 250. Listen carefully to the exhaust noise or ‘note’, as you do not want it to be ‘4 stroking’. If it is, it needs to be leaned slowly until it runs 2 stroke. You can tell it is 4 stroking if it is very “boggy” and “hesitant” in acceleration and running. If it is making that “burbling” sound then it is 4 stroking which means it is running too rich and therefore too cold. If you are getting boggy and burbling sound when you go to WOT turn the HSN very gradual increments and you will hear it at some point clear up with a clean 2 stroke sound.

Everyone thinks they have to run it super cool and check to be sure temps are low. That's not what it is about. The reverse is true! Cool operation is damaging operation. Little, if any, break-in will occur unless it is heat cycled properly.

The manufactures can’t make a piston/sleeve turn over smoothly at room temp, because when the engine runs the sleeve will expand and there will be no seal at operating temp. See how that makes sense?!

So preheat it if necessary and don't run it cool, and heat cycle it, and you'll be good to go! After you have done this several times then you can gradually lean out the HSN to get best performance, but it should then be richened up just rich of peak to ensure it lasts long too. Running it at max peak rpm will lead to the shortest useful life of the piston and sleeve. If racing that is fine but if you are just playing and bashing you may want to run just a little richer than that peak setting. Racers pistons and sleeves don’t last nearly as long because they race them so leaned out to get best performance, but you cant do that too long. After the HSN is set then it is time to set the low and/or mid range needles and idling setting.

I see a lot of people idle the engine for a tank and then they let it cool off thinking that they are "heat cycling" it. However, because they are not running it up to WOT it is not generating enough heat to be of any use to a breakin/heat cycle. So, inadvertently by idling they are just letting the engine sleeve and piston wear and grind away the taper at the top from the cold tight fit that they are allowing to happen when idling away on the bench. Research has shown that basically no break-in effect takes place AT ALL unless the engine is allowed to come up to operating temp and for at least 2 minutes. So if you are idling away and then let it cool there is zero break-in/heat cycle benefit. But if you want to wear away the sleeve and piston fit and therefore wreck an engine, then prolonged idling will definitely do it for you!

As you do several 2 - 3 minute runs, you will see the engine come alive right before your eyes. It will respond to throttle quicker, accelerate better and show its power right in front of you.

So to paraphrase a proper break-in is:

Run the engine for at least five 2-3 minutes runs bringing the engine to WOT passes during those runs. Let it cool down between each run and make sure you move the piston to BDC by turning the flywheel manually.

If you use that (proper!) method you will quickly, properly and efficiently break-in a new nitro ABC, ABN, AAC (non-ringed) engine. You wont waste time, effort, and fuel by mindlessly letting it idle away destroying the piston and sleeve.

I hope this is helpful!!

P.S. If you want to hear it from him, read Dave Gierke’s article in the January 2002 issue of “RC Nitro” magazine!

ShoestringRacer

Here is directly taken from the O.S. Engines website:

http://www.osengines.com/faq/product-faq.html#q590


"How Do I Break In My R/C Car Engine?
The break in process of model engines, especially R/C car engines has been affected by a wide variety of myths and misconceptions. The main one is that the engine must be run at idle for several tanks' worth of fuel before the model is run. There is nothing farther from the truth! In fact, running the engine at idle for several tanks' worth of fuel will not only insure that your engine won't break in properly, but it could also reduce its overall life!

The purpose of the break-in process is to run the engine so that its moving parts will polish each other to a perfect fit. This requires that the engine be run at a variety of throttle settings so that the different parts will be affected by changing pressures and temperatures.

Typically, we start out with a moderately rich needle setting and start driving the car right away. We accelerate to a medium speed and then coast. Turn around and come back the same way. If the high-speed needle is so rich that the engine tends to hesitate a lot when throttle is applied, we'll lean it a bit to eliminate most of the hesitation.

After a few minutes of this, we start accelerating to a high speed and then coast. Turn around and come back the same way. We do this for the remainder of the first tank.

During the next two to three tanks' worth of running, we gradually lean the high-speed needle valve until the engine will run at full throttle at a setting just rich of peak RPM. One way to tell that the engine is on the rich side of peak RPM is to accelerate to full throttle and carefully listen to the engine. It should accelerate up and hold RPM, and not sag back down.

With the CV-series of engines, we'll set the high-speed needle about 2-1/4 turns open and lean from there. When fully leaned, the needle will be between 1-3/4 to 2 turns out from closed. The engine may still run with a leaner setting on the needle, but that setting may be lean enough to allow the engine to gradually overheat and quit. An overheat is a bad thing, and it will cause the piston/cylinder fit to go bad very quickly. "Thermal overload" is just another term for overheating.

If the engine is set too lean, the engine's internal parts can be damaged because they'll be starved of lubrication. Remember, the engine's lubrication is contained in the fuel, and a too-lean setting means too little fuel, which translates into too little lubrication.

Finally, O.S. states in their engine instructions that you should use a fuel that has an oil content of no less than 18% by volume. Many so-called "R/C Car" fuels contain oil in the 12%-14% range. While these may work quite well when the engine's set correctly, low-oil fuels do not leave much margin of error if the engine gets a lean run. Nitro content can be as high as 20% by volume without worry about special engine tuning or setup."

dhyde79

uhh yeah
finish reading it, that article, or the other one I read that're almost identical, BOTH say that break in isn't finished till you've gone through a full gallon...

my question was, baby it for that gallon, or treat it like it's going to be run.....?