40151-ZY6-010ZA Honda COVER, FR. SEPARATE *NH282MU* (OYSTER SILVER METALLIC-U)

If technical assistance in the interpretation of the test data is necessary, contact your Caterpillar Product Analyst in Service Engineering.Flow Chart For Troubleshooting Engine Vibration In Vehicular Equipment
Discussion Of Troubleshooting Procedure
The complete troubleshooting procedure outlined in the flow chart on page 3 consists of seven basic steps. 1. Fill out Engine Vibration Questionnaire (vibration meter not required).2. Repair all defects suggested by the questionnaire.3. Take in-chassis vibration data.4. Interpret the data and repair all suggested defects.5. Take in-chassis vibration data again.6. Take isolated engine vibration data.7. Determine if engine vibration complies with Caterpillar allowable levels.Each of the above steps, including completion of the data sheets and interpretation of vibration measurements, is discussed in detail in the following sections of this instruction. If the vibration problem is solved before completion of the entire troubleshooting procedure, it is not necessary to continue with the procedure.If an engine fails to comply with Caterpillar Tractor Co. allowable vibration levels in the isolated engine test, consult your Service Engineering Product Analyst for advice on repair.The engine vibration questionnaire is shown on the next page. The vibration test data sheets are shown on pages 10 and 12. Additional data sheets for the in-chassis test and isolated engine test can be obtained in pads of 50 sheets by ordering Special Instruction Form SEHS7915.Instructions For Filling Out Engine Vibration Questionnaire
The first step in the troubleshooting process is to fill out the engine vibration questionnaire. The purpose of the questionnaire is to record the history of the vibration problem and to identify possible non-engine causes of the vibration. After completion of the questionnaire, if it is determined that the vibration occurs only when the vehicle is in motion or only when the engine is under load, then the engine is not the cause of the vibration. Instead, look for drive train components that are out-of-balance or components that have been deformed due to torque reaction.Comments about suspected components are listed on the questionnaire. If "non-engine" sources of vibration are discovered, consult the chassis manufacturer for assistance.If the vibration occurs when the vehicle is stationary with no torque load on the engine, proceed to the in-chassis vibration test. Interpretation of the data from the in-chassis vibration test will provide information about the cause of vibration and possible corrective action. Because of the large variety of engine configurations and mounting systems, it is not possible to establish allowable levels for in-chassis vibration. The only reliable method to determine if the engine complies with the Caterpillar Tractor Co. allowable levels is to perform an isolated engine vibration test.In some circumstances, even if the vibration occurs only when the vehicle is moving or the engine is under load, it may be necessary to verify that the engine vibration is within specification. Under these circumstances, proceed to the isolated engine vibration test and determine if the isolated engine complies with Caterpillar's allowable vibration levels.Engine Vibration Questionnaire For Vehicular Equipment Vibration Terms And Units
Displacement AmplitudeThe total "back and forth" distance traveled by a body in one cycle of vibration. This peak-to-peak measurement is usually expressed in mils (.001 inches) or in microns (.001 mm).Filter-InMethod of operating the vibration meter where a tuneable filter is used to determine displacement amplitude at a specific frequency.Filter-OutMethod of operating the vibration meter to determine overall displacement amplitude. The tuneable filter is not used.Firing FrequencyFrequency at which an engine fires. For a four cycle engine, the firing frequency = 1/2 x crankshaft rotational frequency x the number of cylinders.FrequencyThe number of vibration cycles during a specific period of time. Frequency is usually expressed in cycles per second (cps) or cycles per minute (cpm).HertzUnit of measurement for frequency equivalent to cycles per second; abbreviated Hz.Linear Vibration"In-line" or "back and forth" vibration of the engine block or other equipment. Linear vibration can be measured with a vibration meter equipped with a hand-held probe, such as the IRD Model 320 Vibration Analyzer.MicronMetric unit of measurement for displacement amplitude - 1 micron = .039 mils.MilEnglish unit of measurement for displacement amplitude - 1 mil = 25.4 microns.Natural FrequencyThe frequency at which a body will vibrate if subjected to a sudden blow.OrderThe order of vibration is the ratio of vibration frequency (cpm) to the crankshaft rotational frequency (rpm). Order of Vibration = Vibration Frequency (cpm)/Engine Speed (rpm)Overall Displacement AmplitudeThe total amount of displacement after the contributions from all frequencies are properly phased together. A vibration meter in the filter-out mode is used to determine this value.ResonanceThe condition that exists when a body is excited by a force at the same frequency as the body's natural frequency. At resonance, large displacement amplitudes can be produced by small exciting forces.Performing An In-Chassis Vibration Test
Use the data sheet shown on page 10 to record the in-chassis measurements. A data sheet should be completed for the initial test and for all subsequent tests where modifications have been made. By doing this, a complete record will be maintained for all vibration tests. Normally, the initial test is for a vehicle in the "as received" condition that has objectionable vibration. Additional tests should be performed for each modified condition such as: Fan belts removed, engine mounts realigned, clutch disengaged, etc. Specify each test condition in the space provided on the data sheet.(A) Probe Locations
The probe of the vibration meter should be placed on the engine block as close as possible to the centerline of the crankshaft at the following locations: 1. Front Horizontal2. Front Vertical3. Rear Horizontal4. Rear Vertical5. Rear AxialVertical measurements can be taken from either the top or underneath the engine. Horizontal measurements can be taken from either side of the engine. The rear axial location (parallel to the crankshaft) should be as close as possible to the centerline of the crankshaft, but due to rotating components, the point normally selected is above or below the centerline of the crankshaft. At all five of the locations, the probe must be positioned against the cast iron cylinder block and not against the valve covers, tubing, sheet metal, or