Hi. My name is Alex. I live in New York. Since I was 9, I'v been intrested with gas powered R/C models. Now 13, I have a Duratrax Maximum ST,t which you can check out at my link page.Also I have a traxxas nitro 4 tec. Drive the 4 tec before you buy it, I don't like the way on road cars handle.Here is a magizine report from R/C CAR Magizine. How to Break-In Your Car Engine: ITS ALL IN THE CARB. Everything that's needed to ensure your engine's long life in contained in it's carurator. Most carbs have three adustments that you'll need to familiarize yourself with. The first, and most important, is the high speed needle setting. This needle valve controls the mixture of fuel and air that enters the engine's combustion chamber during high - rpm running. More fuel in this mixture causes a rich condition while less fuel and more air causes a lean condition. a richer high - speed neddle settting will actully help the engine run cooler ( since it reduces rpm ) and since there is more fuel passing throught the combustion chamber it actully liquid cools a bit. A leaner setting will allow the engine to acheive a higher rpm, but will also casue it to run much hotter. A properly set high-speed needle valve will provide a comprimise between a cool running temp. and a high rpm. Needless to say, extremes in either direction in either direction arn't good. Many racing engines also have a secondary needle valve adjustment that is used to contol the engines low-speed air/fuel mixture. This needle is used to adjust the way a engine makes a transition from low to a high rpm. It also helps control the air/fuel mixture when the engine is idling. A low speed neddle setting that is rich will reduce throttle response at low rpm, making the car sluggish coming out of turns. A lean setting will have the setting will have the same effect. A correct setting will allow the engine to make more power during low rpm operation. Many modern sport type engines have eliminated the low speed needle completly. While this doesn't allow the highest level of tuning for the experienced modeler, having one less neddle adjsutment to have to worry about is nice for begginers. Finaly, there's the idle stop screw. Basically, this screw is used to keep the carb's slide barred from completely closing which would odviosly shut off the engine. Setting this needle is done after the high and low speed neddles are set. Never use the radio's throttle trim to set the idle speed.Tis is a common mistake made by beginers. Always use the idle stop screw. WHERE TO BEGIN? READ THE BOOK! Before you even place your car on a starter box or pull it's pull starter read the manual. Most nitro kits have a section in the manuals that tell where the settings should be. The most exspensive engines follow more closely to the actually setting that the sport type engines. For sport type engines, the neddle position that the book says is actully way off to get the engine to fire and run. If a new engine won't fire, lean the high speed neddle setting in small increments. Once it is running, slowly put the needle valve back to the setting suggested in the book. Never run a engine to lean! YOUR NEW ENGINE'S FIRST RUN We know that you want to go out and do some hot laps the instant your new engine roars to life - BUT DON'T! The first few runs of your engine are critical. Once your engine starts, place it on a stand so that the wheels can't touch the ground. Let the engine idle at low rpm for a feew minutes, (2 or 3 miutes will do) blipping the throttle every 15-30 seconds. Then shut down the engine and let it cool. During the cooling process, it is very important to make sure that the piston is not at the top of the cylinder. To tell where the piston is, when it's shut off, turn it over a few times. When it gets at the hardest time to turn it, it is at the top. The easier times is when the piston is at the bottom. Now your ready to run those hot laps, right? Wrong! do the obove steps 3-4 mor times. YES, YOU CAN DRIVE IT NOW After you've heat cycled your engine, you can finally put it on the track. But don't get to excited yet, you must run it with a very rich high-speed needle setting. Some engine experts suggest that you set it so rich that the engine four strokes. It may be better this way, because the fuel will take some of the heat and any timmy metal particals created in the break in prosses right out the exaust! I doesn't matter if you four stroke it or not, the choice is yours, and it's not going to damage your engine which ever way you do it.During this procedure, it is vital that you avoid proloned use of full throttle, which could strain the engine becasue of the hifh amount of fuel. Instead, you should blip the throttle, and avoid to much time around a particular rpm. Run the engine in these settings for a few tank fulls of fuel. NOW COMES THE GOOD PART Once you've put through about 6 tanks of fuel through your car, as outlined above, it's time to start leaning the high speed needle valve and making some power! Begin by leaning it in hour increments, ( turning it in clockwise, as if it looked like a clock). Run the car for a minute or so, then bring it back in and lean it out by another hour increment. Repeat this until the engine acheives a good rpm, but you shouldn't allow it to scream quite yet. Run a few tank fulls in this setting. THE FINAL STEPS Now that you've found a good high speed setting for the high speed needle and gives you good rpm but still pushes alot of blue smoke out the exaust, it's time to set the low speed needle and idle stop screw. Most engine manufactuers recommend a specific setting for the low speed needle calve and the idle stop screw. For now, set the idle stop screw so that the engine will idle at moderate rpm without stalling. Bring the engine up to operating temp by running it a few minutes. Now stop the car and listen to the idle speed. If the engine idles fast but then slows down in jsut a few seconds, the low speed needle is probably set too rich. Lean the low-speed needle by turning it clockwise in hour icrements until, after running a few more laps, the idle stays high for about 20 seconds. Once you've done this, use the idle stop screw to set the idle to a moderate rpm. Ideally, a engine should be able to idle for 20 seconds whithout change in rpm. For sport engines that lack a low speed needle setting, the idle stop screw is the only way of adjusting the low end speed. For these engines, simply turn the idle-stop screw clockwise to increase idle speed, and counterclockwise to decrease it. The idle speed should be high enough for the engine to run without out it stalling, but low enough so you don't have to hold the brake for it to stay still. ENJOY YOUR NEW NITRO POWERED VEHICLE This information was taken out of the R/C CAR MAGIZINE, march 1999 copy. Info provided by Ron Paris. TIPS: Use fuel with a nitro content between 10 and 20 percent. 1. rich is good, Blue smoke should always be coming from the exaust. 2. Always set the high speed needle first. 3. Never try to tune a cold engine, always bring it up to operating temperature. 4. Always begin tuning with a rich setting, never a lean one.
