0330275 JOHNSON LINK, Spark advance

Required Information
Ignition Timing
A complete fuel analysis must be conducted prior to putting the engine into service. Obtain a fuel analysis in order to determine the fuel energy content and calculate the methane number. The methane number indicates the ability of the fuel to be ignited. The methane number is determined when you input the data from the fuel analysis into the Methane Number Program, LEKQ6378. Use the methane number and the Engine Performance, "Fuel Usage Guide" in order to determine the ignition timing.Obtain several samples of fuel if the quality is expected to change. If the methane number will vary during engine operation, use the lowest expected value in order to determine ignition timing.Maximum Load
Refer to the Data Sheet on engine performance from Technical Marketing Information (TMI) to determine the power level for altitude, temperature, and methane number. Use the information in the Engine Performance, LEBQ6117 in order to determine the maximum engine load. The desired engine load must not exceed the maximum engine load.Inlet Manifold Pressure at Full Load
Use the inlet manifold pressure to estimate the engines load. The inlet manifold pressure may be used if the engine timing and the exhaust NOx are set properly. Refer to the Data Sheet on engine performance from TMI to determine inlet manifold pressures for specific settings of timing and emissions. If the engine power is derated, interpolate the desired inlet manifold pressure between the 100 percent and the 75 percent load ratings.Level of Exhaust Emissions
The 156-1060 Emissions Analyzer Gp or another emissions analyzer is required in order to set up a gas engine. The engines performance Data Sheet gives the levels of emissions for engine loads of 50 percent, of 75 percent, and of 100 percent. Set up the engine in accordance with the Data Sheet at the desired full load with the data that was taken at 100 percent load.Note: Use NOx levels to set up the engine, when possible.Gas Pressure Regulator
The gas pressure regulator requires adjustment when the engine is installed. Use only Caterpillar approved regulators in order to avoid problems with performance. A balance line for the regulator is required on all gas engines. This line compensates for changes in boost pressure or in air filter restriction.Note: The supply line to the gas pressure regulator must be of adequate diameter to provide constant pressure to the regulator for all power ranges. Do not use supply lines that are smaller than the inlet to the pressure regulator.Requirements for the Electrical System
All of the wiring must conform to the requirements of CSA Class 1 Division 2 Group C,D. The wiring must also conform to all other codes that are applicable to the site.When you route the wiring, avoid acute bends and sharp edges. To protect the wiring harnesses, route the harnesses through the metal conduit. A liquid tight conduit is recommended. Use proper support and alignment in order to avoid strain on the conduit.The engine control system requires a clean 24 VDC power supply. The maximum allowable AC ripple voltage is 150 mV AC peak to peak. For the wiring, the maximum allowable voltage drop is 1 VDC from the power supply to the Electronic Control Module (ECM) or to an actuator. The power supply capacity has to be 20 amps of continuous power.The circuit for the engine control system must be separate from the circuit for the electric starting motor.Grounding Practices
Proper grounding is necessary for optimum engine performance and reliability. Improper grounding will result in electrical current paths that are uncontrolled and unreliable.Uncontrolled electrical circuit paths can result in damage to main bearings, to crankshaft bearing journal surfaces, and to aluminum components. Uncontrolled electrical circuit paths can also cause electrical activity that may degrade the engine electronics and communications.
For the starting motor, do not attach the battery negative terminal to the cylinder block.
Use an electrical ground strap to connect all metal cases that contain electrical components or electronic components to the cylinder block.
Do not connect the negative terminal from the electrical power supply directly to the cylinder block. Connect the negative terminal from the electrical power supply to the negative terminal "−" on the interface box.
Ground the cylinder block with a ground strap that is furnished by the customer. Connect this ground strap to the ground plane.
Use a separate ground strap to ground the battery negative terminal for the control system to the ground plane or to earth ground.
Rubber couplings may connect the steel piping of the cooling system and the radiator. This action causes the piping and the radiator to be electrically isolated. Ensure that the piping and the radiator are continuously grounded to the cylinder block. Use ground straps that bypass the rubber couplings.
Ensure that all grounds are secure and free of corrosion.Proper Welding Procedures
Proper welding procedures are necessary in order to avoid damage to electronic controls. Perform welding on the engine according to the following procedure.
Set the engine control to the "STOP" mode.
Turn OFF the fuel supply to the engine.
Disconnect the negative terminal from the power supply.
Disconnect the following electronic components from the wiring harnesses: ECM, throttle actuator, fuel actuator and sensors.
Protect the wiring harnesses from welding debris and/or from the welding spatter.
Do NOT use electrical components (ECM or ECM sensors) or electronic component grounding points for grounding the welder.
Connect the welders ground cable directly to the engine component that will be welded. Place the clamp close to the weld to reduce the possibility of welding current damage to engine bearings, electrical, and engine components.
Use standard welding procedures to the weld the materials together.Service Tools
The tools that are listed in Table 1 are required in order to perform the electrical installation and the initial start-up.
Table 1
Service Tools    
Pt. No.    Description    Functions    
N/A     Personal Computer (PC)     The PC is required for the use of Cat ET.    
"JERD2124"     Software     Single user license for Cat ET
Use the most recent version of this software.    
"JERD2129"     Software     Data subscription for all engines    
275-5120 (1)