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• How the Engine Works •
The CEN nitro engine is a two-stroke, air-cooled engine. It features a true "ABC" (Aluminum, Brass, Chrome) construction. The chrome sleeve has a slight taper so the aluminum piston fits tighter towards the top of the sleeve compared to the bottom. When the engine reaches proper operating temperature its perfect running tolerances will then be achieved. The piston will feel tighter when the engine is cold.
Fuel enters the engine through the carburetor where it is mixed with air. The fuel/air mixture is then drawn into the crankcase. The crankshaft has a rotating valve, which opens and closes the crankcase to let fuel into it. On the pistons down stroke, the crankcase becomes pressurized, and fuel is blown into the combustion chamber through intake ports cut into the sleeve. On the upstroke, the fuel is compressed and ignited. When first trying to start your engine, the electrically heated glow plug causes the fuel to ignite. Once the engine is running the fuel is ignited by rapid compression in the combustion chamber. The exhaust is then released through a third port in the sleeve.
The oil that is contained in the fuel mixture lubricates the surfaces of the piston and the sleeve. The oil in the fuel also helps to cool the engine while running. Some of the oil is burned when in the combustion process which is what creates the blue smoke trail from the car.
The air to fuel mixture is critically important. A mixture that is too "rich" means that there is too much fuel, a mixture that is too "lean" means that there is not enough fuel for the given amount of air. When the mixture is too rich, performance will be sluggish. There is also a high potential to foul the glow plug when running the car too rich. When the mixture is too lean, there is not enough oil to lubricate and cool the engine parts. Running too lean will almost certainly damage internal engine parts as well as foul the glow plug.
• Required Equipment •
To operate your new engine you are going to need the following items. These items should all be available on www.customrccars.com or from a local hobby dealer.
- Glow heater/glow igniter (part# G70402)
- Model engine fuel formulated for cars between 10-20% nitro content. (Must be bought from a hobby shop)
- Fuel bottle, needed to fuel up your gas tank.
- Small Phillips and flat head screw drivers. Needed for making adjustment to carburetor.
- After-run oil. Should be used after running the engine to prevent rust and corrosion. (Must be bought from a hobby shop)
- Spare glow plugs. Glow plugs will always be one of the first items to go bad in a nitro engine.
- Air filter; never run your engine with out a good quality air filter.
- 5/16-inch nut driver or glow plug wrench.
• Fuel •
Always read and follow all of the instructions on your fuel bottle. Nitro fuel is very flammable and poisonous.
Fuel is the most important component for making your engine run and perform properly. Poor fuels will cause hard starting, poor performance and excessive wear of the engine.
There are many good brands of fuels on the market. You may use any of them as long as they meet the basic minimum requirements.
- Fuel must be a castor and synthetic oil blend with total oil content of 12-18%
- 3-5% castor oil must be used in a synthetic/castor oil blend of fuel.
- Nitro methane (Nitro) content should be around 10-20%.
The best fuels on the market today are castor/synthetic blends. The castor provides high temperature lubrication while the synthetic oils help prevent varnish build up inside the engine. The higher quality fuels also contain anti-wear agents, anti-foaming agents, lubrication additives, and rust and corrosion inhibitors. Use fuels that are made for use in cars, not airplanes. (Airplane/boat fuel is ok for marine engines) Car fuel will give better performance with easier tuning, and longer run times.
• Radio System Operation •
Install 4 "AA" batteries in the receiver pack on the car. Next install 8 "AA" batteries in the transmitter. Pull out the battery holder in the transmitter located at the bottom. Put in batteries correctly and replace with the metal tabs lining up on both the battery holder and the transmitter.
- Turn on the radio system and check that all servos are working correctly. Check all the linkages to make sure they are not binding. *Always remember; the transmitter is the first to be tuned on and the last to be turned off. Never turn off the radio when the engine is running. To stall the engine you can either run it out of gas or pinch the fuel line until it stalls. The switch on the car only turns off the electronics in the car, not the engine.
- Always make sure the batteries in both your car and your radio are strong or fully charged. Attempting to run your car with weak batteries will make the car not respond to users controls. It could even completely become uncontrollable and become a "runaway car" and severely damage the car.
- Check the wires from your battery and your antenna wire every few runs. These wires could become damaged and result in loss of control.
- Before starting the engine, always check the range of the transmitter before running the car. Short range can be the result of a broken antenna wire or weak batteries.
• How to Start the Engine •
CEN Racing has made a running change to your fuel tank. The new tank now includes a filtering stone and we have removed the primer pump. We found the removal of the primer and the addition of the stone to produce a more reliable fuel system. Use the following steps to start your engine.
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To start your engine
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Step 1:
Charge your glow igniter or glow heater.
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Step 2:
Fill your fuel tank with high quality 20% nitro fuel.
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Step 3:
Plug the exhaust outlet with your finger and pull the pull starter 3-4 times. Watch for fuel to fill the fuel line. Once you see fuel get to the carburetor take your finger off the exhaust outlet.
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Step 4:
Put your glow igniter onto your glow plug. Give the engine 1/4 - 1/2 throttle using the transmitter and pull the pull cord with short quick pulls. No need to pull it more than 5-6 inches out.
Warning: pulling more than 5-6 inches will bend the spring and may snap the cord. |
Important Note: Attempting to start a hot engine may prove to be difficult. If engine is hot and difficult to start, let it cool down completely then try again.
To turn off your engine: Follow these simple steps when you are done running your engine. Please keep in mind that model car fuel is very corrosive and it's best to burn all the fuel out of the engine at the end of your race. Simply run your fuel tank dry and the engine will burn all excess fuel that's in the fuel lines and inside the engine. Recommend that you always use after run oil at the end of each days running.
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Here are two different ways to stall your engine before you run it out of fuel.
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1: Simply use a rag to block the exhaust flow from the muffler/ tuned pipe.
be careful the pipe may be very hot.
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2: Pinch the fuel line that feeds the carburetor with fuel. The engine will rev. up then stall. This is normal because the engine is being leaned out due to lack of fuel.
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• Breaking-in the Engine •
Notice:
CEN high performance engines must be correctly broken-in for maximum performance and life! Rushing this process can result in premature engine failure.
One important thing to remember when breaking in a new engine, it will appear to not run correctly. It will stall, operate very inconsistently, and may even foul glow plugs. Don't get frustrated with it. Just keep working with it and it will become a smooth running engine. These experiences are what can be called "break-in pains". Every new engine has to go through this. When you get the engine started, be sure to keep it running by giving it throttle when it sounds like it's going to stall. Pulling the throttle quickly can also stall the engine. After a couple of tanks your patience will pay off with a very strong, reliable running engine.
Break-in should be done using at least 4-5 tanks of fuel. Please don't take short cuts and run less tanks. Don't listen to your friends that tell you that it doesn't really matter, IT DOES!
Its best to break-in the engine using the same nitro content as you plan to use for everyday use. The engine should be broken-in on a smooth hard surface. For a boat engines, try to find smooth clam water. Try to avoid breaking-in the engine on very hot, or humid days.
Turning the mixture screws clockwise will "lean" the air/fuel mixture. This will increase power and increase engine temperature. Turning the screws to the left counter-clockwise will "richen" the air/fuel mixture. This will cool the engine and make it last longer. When adjusting the idle screw, turning to the left will lower the idle and right will raise the idle. Remember to open the carburetor a little whenever you tighten the idle screw to prevent breaking off the tip of the screw.
Always break-in your engine without the body on the car, you want as much airflow as you can get to keep the engine cool. Do not run the engine too lean or you will over heat it and cause permanent damage to the internal components of the engine.
It is normal for the engine to consume a lot of fuel during break-in. This is because you are running it "richer" than you normally would to keep the engine cool and to flush out the engine as the parts "seat" themselves. Because of the richer than normal setting the performance of the engine will be limited. After break-in, you will then lean it out to gain performance.
It's always a good idea to get an extra glow plug (short, cold plug). It is normal to have to replace it after break-in because of the deposits left on in from the break-in process. Glow plugs are a normal item that needs replacing. Because they have such a huge influence on they way your engine runs it best to always have a few spares on hand.
- Start your engine, drive the car slowly around to let the engine heat up. Ease the throttle on and off slowly. Don't let the car stay still for long periods of time, this will heat up the clutch bell and could damage it.
- The idle speed should be set as low as possible to keep the engine running when the car is stopped.
- The final settings on the top end needle will vary slightly from engine to engine. Look for the following performance signs:
- Engine should accelerate quickly.
- Blue/white smoke coming from the exhaust pipe. If no blue smoke it coming out, you need to "richen" the top end needle.
- Alternate driving at low to medium speeds, with short periods of high speed running
- When the engine reaches normal running temperature, it will pick up speed and performance will improve.
- When the tank is close to running out bring in the car and shut off the engine. Let it cool completely, then refuel and run again. Part of the break-in process is also to heat cycle the parts in side the engine.
- Remember always run the engine with a clean air filter.
• Signs of Overheating •
If your engine stalls from overheating it most likely has caused damage to the components inside of it.
The simplest way to test for over heating is to put a drop of water or spit on top of the engine head. If it boils away instantly shut the engine down and let it cool off. If it takes 5-7 seconds for the water to evaporate away, then the engine is running at a good temperature. Hobby shops sell temperature guns that tell you what they are running at. Ideally you want it to run around 260 degrees.
• After Running •
After you have used your car for the day and are ready to store it here are some things you should follow to keep it in top shape for the next time you use it.
Because there is methanol in the fuel any left inside of the engine will attract moisture. This could cause corrosion on the internal parts of the engine. To combat this you should do the following.
- Drain the fuel tank completely
- Using your glow heater start the engine and run it until it burns all of the fuel that in the lines and in the engine out.
- Remove the air filter and apply 6 drops of after run oil into the carburetor. Now pull the pull starter a few times to circulate that oil. Do not use the glow heater for this step! Do not store your car with fuel inside of it.
- Clean off any fuel that remains on the car. Clean off any dirt or debris that remains on the car as well.
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