CONE-BEARING 3F7183 - Caterpillar

Records of engine performance are an important element of a maintenance program. The data on engine performance can help to predict problems with operation. Also, the data can provide information that is useful for achieving optimum operation.Traditionally, data on engine performance might be recorded regularly. However, the data might not be reviewed until the occurrence of a problem. This method of monitoring engine operation has several disadvantages:
The engine may not be providing optimum performance which may not be noticed because the engine does not exhibit excessive changes in performance.
Because a problem occurs, the engine may be in an alarm condition that requires a quick response.
Repairs may cause more downtime.
The cost of downtime is compounded by the cost of parts and labor for repairs.The absence of an alarm condition does NOT guarantee normal operation. Not all parameters have alarms and/or shutdowns. Setpoints for alarms are outside of the normal ranges in order to avoid occasional nuisance warnings. An alarm indicates a serious condition that requires immediate attention. Service or repair is a reaction to an alarm condition.A different approach is necessary in order to schedule service before an alarm condition occurs. Monitor the trends of the engine performance. The following benefits can be realized:
Reduction of engine performance will be noticed sooner.
Problems can be predicted. Monitoring the trend enables prevention of the problems. Service can be planned before an alarm condition occurs.
Planning for downtime will also reduce downtime.
The cost of parts and labor for service that is planned will be less than the cost of repairs that are not anticipated.Monitoring the Trends of Engine Performance
To maintain a program that is successful, several factors are important:
Record the data regularly when the engine is operating at similar loads and speeds.
Obtain accurate data.
At regular intervals, review the data in a graphic format.
Perform corrections before damage and/or downtime occurs.Accurate data is provided by accurate instruments and proper use of the instruments. The gauges and the sensing devices must be in good condition. This condition is especially true for thermocouples. Establish a program for calibrating the instruments periodically. Avoid using infrared thermometers for obtaining data. Be sure to read the gauges properly. Accurate recording of the data is also important.Use the following Steps to establish a program.
Establish a baseline for the engine parameters. The baseline is necessary in order to know the normal gauge readings. The new data will be compared to the baseline.
Use the data from the engine commissioning. The data is recorded for various loads. The data is recorded before any wear or deterioration takes place.
If there is no data from the engine commissioning, use data from the engine test cell. Understand that the data will not be specific to the site.
If data is not available from the engine commissioning or the engine test cell, calculate an average of the existing data.
Establish a new baseline after an overhaul.
Frequently record the new data during engine operation. For an example of a log to use, see this Operation and Maintenance Manual, "Hourly Performance Log" (Reference