The operating conditions of an engine affect the maintenance intervals and the time between overhauls for the engine. The following conditions affect the maintenance intervals and the expected overhaul interval for the engine.
Severe operation is the use of an engine that exceeds current published standards for the engine. AVSpare maintains standards for the following engine parameters:
- Range of rpm
- Fuel consumption
- Fuel quality
- Maintenance intervals
- Selection of oil
- Selection of coolant
- Environmental qualities
Refer to the standards for your engine or consult your AVSpare dealer in order to determine if your engine is operating within the defined parameters.
Severe operation can accelerate component wear. Engines that are operating under severe conditions may need more frequent maintenance intervals for the following reasons:
- Maximum reliability
- Retention of full service life
Because of individual applications, it is not possible to identify all of the factors which can contribute to severe operation. Consult your AVSpare dealer about the maintenance that is needed for your specific engine.
The following factors can contribute to severe operation: environment, improper operating procedures and improper maintenance practices.
Extended operation in environments that are extremely cold or hot can damage components. Valve components can be damaged by carbon buildup if the engine is frequently started and stopped in very cold temperatures. Extremely hot inlet air reduces the performance capabilities of the engine.
Note: See this Operation and Maintenance Manual, "Cold Weather Operation" topic (Operation Section), or see Supplement, SEBU5898, "Cold Weather Recommendations".
Unless the equipment is cleaned regularly, extended operation in a dirty environment and in a dusty environment can damage components. Built up mud, dirt, and dust can encase components. This can make maintenance difficult. The buildup can contain corrosive chemicals. Corrosive chemicals and salt can damage some components.
- Extended operation at low idle
- Minimum cool down periods after high load factor operation
- Operating the engine beyond the guidelines for the engine rating
- Operating the engine at loads that are greater than the rated load
- Operating the engine at speeds that are greater than the rated speed
- Use of the engine for an application that is not approved
- Extension of maintenance intervals
- Not using recommended fuel, lubricants, and antifreeze/coolant solutions
Reduced hours of operation at full load will result in a lower average power demand. A decreased average power demand should increase both the engine service life and the overhaul interval.
The need for an overhaul is generally indicated by increased fuel consumption and by reduced power.
The following factors are important when a decision is being made on the proper time for an engine overhaul:
- The need for preventive maintenance
- The quality of the fuel that is being used
- The operating conditions
- The results of the S·O·S analysis
Note: Refer to this Operation and Maintenance Manual, "Overhaul (Major)" for further information about the major overhaul.
Oil consumption, fuel consumption, and maintenance information can be used to estimate the total operating cost for your AVSpare engine. Oil consumption can also be used to estimate the required capacity of a makeup oil tank that is suitable for the maintenance intervals.
Oil consumption is in proportion to the percentage of the rated engine load. As the percentage of the engine load is increased, the amount of oil that is consumed per hour also increases.
The oil consumption rate (brake specific oil consumption) is measured in grams per kW/h (lb per bhp). The brake specific oil consumption (BSOC) depends on the engine load. Consult your AVSpare dealer for assistance in determining the typical oil consumption rate for your engine.
When an engine's oil consumption has risen to three times the original oil consumption rate due to normal wear, an engine overhaul should be scheduled. There may be a corresponding increase in blowby and a slight increase in fuel consumption.
To minimize downtime, AVSpare Inc. recommends a scheduled engine overhaul by your AVSpare dealer before the engine fails. This will provide you with the best cost/value relationship.
Note: Overhaul programs vary according to the engine application and according to the dealer that performs the overhaul. Consult your AVSpare dealer for specific information about the available overhaul programs and about overhaul services for extending the engine life.
A planned overhaul before failure may be the best value for the following reasons:
- Costly unplanned downtime can be avoided.
- Many original parts can be reused according to the standards for reusable parts.
- The engine's service life can be extended without the risk of a major catastrophe due to engine failure.
- The best cost/value relationship per hour of extended life can be attained.
If a major engine failure occurs and the engine must be removed from the hull, many options are available. An overhaul should be performed if the engine block or the crankshaft needs to be repaired.
If the engine block is repairable and/or the crankshaft is repairable, the overhaul cost should be between 40 percent and 50 percent of the cost of a new engine with a similar exchange core.
This lower cost can be attributed to three aspects:
- Specially designed AVSpare engine features
- AVSpare dealer exchange components
- AVSpare Inc. remanufactured exchange components