BEARING 1956901 - Caterpillar

Adjustments to the precombustion chamber needle valves should not be made when the engine's control strategy is operating in the "feedback" mode. The engine's control strategy adjusts the air fuel ratio to maintain the actual combustion burns equal to the desired burn times. Therefore, adjusting the needle valves will not result in different burn times. Adjusting the needle valve will, instead, set the air/fuel ratio to an unknown value, because the engine's control strategy will attempt to correct for this change.
Continual problems with the check valves could be an indication of contaminated fuel gas. If the contamination is in the form of small particles, a fuel filter that has a 0.01 micron filter is recommended. If the contamination is in the form of liquids, then improvements are required in the gas supply system to remove the contamination.The service literature indicates that the preliminary needle valve setting for a G3600 is 4 to 5 turns in the open direction. This only applies when a G3600 is placed into operation or if major work has been completed, such as a top end over haul. Presetting the needle valves on an engine that has been tuned and in operation will make the engine much more difficult to start and more difficult to load. Changes in the lower heating value (LHV) of the fuel while the engine is being adjusted will result in tuning difficulty and will result in improper engine settings. The exhaust emissions should be tested after the engine is tuned. This is in order to verify that the engine was properly tuned.The fuel flow on a G3600 engine will increase when cylinder misfire occurs. This increased fuel flow is the combined result of the unburned gas that is passing through the misfiring cylinder and the increased fuel consumption of the remaining cylinders that must pick up the additional load. The load is based partly on a calculation of the fuel flow. An increase in the fuel flow due to the cylinder misfiring will result in a higher indicated engine load. A cylinder misfire could drive the engine into an overload (load greater than 110 percent) condition. The G3600 engine's control strategy has a fuel limit that allows the engine to operate only up to 110 percent of the engines rated torque at any given engine speed. This limit was established in order to prevent damage to the engine due to excessive engine loads, while still providing a buffer to changing engine conditions. If a G3600 is operating with one dead cylinder, then the indicated load would increase to the following value:100 percent Torque / 5 Cylinders = 14.28 percent Torque per CylinderThe same fuel flow will also pass through the dead cylinder for the following value:(14.28 percent Torque per Cylinder X 5 Cylinders) + 14.28 percent Fuel Flow through the dead cylinder = 114.28 percent Indicated LoadThe 110 percent limit would cause the engine speed to drop. This speed drop could continue until the engine stops if the load