Breaking in the Terra Crusher
The break in procedure for the Terra Crusher .18ci engine is the most critical step towards a powerful and reliable engine. This break in procedure is intended to follow step 7 of the Terra Crusher Starting Manual. Step 9 in the Terra Crusher Starting Manual is replaced with step 9A in this supplement.
The Tamiya Terra Crusher is also equipped with one of the best on-the-fly forward and reverse transmissions in the industry. This transmissions utilizes a one-way clutch to provide seamless shifting from forward to reverse. This clutch will require a short period of “seating in” to fully engage, use the necessary steps covered in this supplement. Failure to follow this procedure will result in damage to the engine and transmission, voiding the warranty.
Nitro: This term is used to describe the type of fuel and R/C model engine uses. The Terra Crusher uses Nitro fuel, which is a blend of nitromethane (nitro), methanol and caster oil. Nitromethane acts a catalyst that helps boost the combustion process in model engines. Mathanol is the stable portion of the fuel that controls the combustion and caster oil cools and lubricates the moving parts of the engine. Nitro is also commonly used to describe the percentage of nitromethane in the fuel. 10 Percent, 15 Percent and 20 Percent nitro are the most common blends found in hobby stores. Higher nitro percentage fuel will produce more power. **15 to 20 percent nitro furl is recommended for the Terra Crusher**
Rich: A rich fuel mixture has a large amount of fuel in proportion to air. Turning the needle counterclockwise will richen the fuel mixture. This condition is safe for the engine, keeping the engine running cooler. A thick blue smoke exiting the exhaust as well as reduced throttle response can identify a rich mixture.
Lean: A lean fuel mixture has a small amount of fuel in proportion to air. Turning the mixture needle clockwise will lean the fuel mixture. A lean mixture will overheat the engine and will result in power loss. Little or no blue smoke and a high pitch operating tone can identify a mixture that is too lean. Operating the engine under a lean condition will result in damage to the engine, voiding the warranty.
Make sure the mixture needle/screw on the carburetor is set to the factory position of 3 turns out. To do this, screw in the needle clockwise on the carburetor until it stops. DO NOT USE FORCE (Forcing the needle further will cause damage to the carburetor). Then unscrew the needle counter clockwise exactly the full turns. The carburetor should now be set for break in. Additional adjustment may be necessary during break in. Continue with step 8 in the Terra Crusher Starting Manual.
Step 9A (Disregard Step 9 in the Starting Manual).
With the engine running at idle, place the Terra Crusher on a stand so the tires are suspended in the air, and remove the body to allow for maximum cooling. The tires should not be rotating very fast, if at all. The engine should be running at an idle very rich, almost to the point of stalling with a considerable amount of unburned fuel exiting the exhaust pipe. If the engine cannot hold an idle and stalls, lean the mixture needle only enough to hold an idle (adjust in 15-degree increments). If the engine’s RPM at idle is too high, richen the mixture needle enough to bring the engine down to a slow idle (adjust in 15-degree increments). After the engine has consumed half of the first tank of fuel, stop the engine by depressing the air cleaner pipe (air filter). Allow the engine to cool down for 10 minutes.
Step 9. B
Refill the tank and restart the engine. Let the engine consume a full tank of fuel at idle but stop the engine before the fuel completely runs out. Allowing the fuel to completely run out will cause unwanted leaning of the fuel mixture. Allow the engine to cool down for 10 minutes and repeat this step a second time.
Step 9. C
Refill the tank and restart the engine. With the body still off, set the Terra Crusher on a smooth flat surface and drive in a 50-foot oval slowly, modulating between idle and quarter throttle. This is also the first step to break in the Terra Crusher’s transmission. During this step, it is normal for the transmission to exhibit slipping in the forward direction. Applying too much throttle will cause excessive engine RPM during this step and may result in damage to the engine. Listen to the engine while driving and do not use more than quarter throttle. During this tank of fuel, the transmission will begin to “seat in.” Continue until the tank is almost empty and stop the engine. Allow the engine to cool down for 10 minutes.
Step 9. D
Refill the tank and restart the engine. Drive the Terra Crusher in a 50-foot oval slowly, modulating between idle and half throttle. The transmission will still exhibit some slipping. Do not to allow excessive engine RPM. A thick blue smoke should be exiting the exhaust. If there is little or no smoke, richen the mixture 10 degrees (counterclockwise). Continue until the tank is almost empty and stop the engine. Allow the engine to cool down for 10 minutes.
Step 9. E
Refill the tank and restart the engine. Drive the Terra Crusher in a 50-foot oval, varying between idle and full throttle (do not allow excessive engine RPM). A thick blue smoke should be exiting the exhaust. If there is little or no smoke, richen the mixture 10 degrees (counterclockwise). Continue until the tank is almost empty and stop the engine. The transmission should now be broken in and the next few tanks of fuel will continue to improve performance.
The engine should also be broken in and further leaning of the mixture should not be necessary for safe operation. During operation, a thick blue smoke should always be exiting the exhaust.