Best break-in method
 

Hey I was just wondering what break-in method would be the best for breaking in my new O.S. .12cv....please post links and/or an explanation of how to do it

RE: Best break-in method
 

Heat cycle.

Never let the engine just sit and idle during break in. Heat the engine up with a heat gun to about 160+ degrees then start it up. You'll want to run it a little rich the first few tanks, but lean it out enough that the engine will warm up to at least 220 degrees. Run it for a few minutes then shut it off. Be light on the throttle. Put the piston at bottom dead center and let it cool at room temp for at least 15 minutes. Then, start it up again, warm it up to around 220 and run it for another few minutes, shut it off, put the piston at BDC, and let it cool at room temp for another 15 minutes. Just keep repeating the process until you run through minimum 6 tanks of fuel. I like to run closer to a quart. Most people think I put too much time into break in, but the better you break the engine in, the better it will run. You should only have to preheat the engine for the first few startups. It is wise to preheat a new engine since the pinch is so tight.

RE: Best break-in method
 

From OS:

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.

RE: Best break-in method
 

I use heat cycle method when I break in my new engines. Valve explained it pretty good. The O.S. method looks pretty good, too.
I like the heat cycle method, as it heats and cools the engine completely for the first few cycles.
I run cycles for about a quart, and then finish the break in by carefully monitoring the heat, and performance for another quart. I have found that break-in doesn't complete, and the engine doesn't run to it's full potential for about the first gallon of fuel.