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Engine Drive Systems: Considerations with Engine Applications - Maintenance

Other than major overhauls, engine service is comprised of routine inspections, minor adjustments and periodic replacement of engine oil, coolant and spark plugs. Detailed records should be kept to indicate when the service is performed and any observations noted during the procedure that reflect the engine condition.

Routine sampling and testing of the engine oil is strongly recommended, as an indication of engine condition. Routine tests should generally consist of three types: chemical/physical, oil condition, and metal wear analyses.

The operating time interval for major overhauls varies considerably, depending on the engine model and its manufacturer as well as on lubrication and maintenance.

A top-end overhaul is performed to rebuild cylinder heads and the valve train. Some manufacturers recommend this work after 12,000-15,000 equivalent full-load hours (EFLH). The turbocharger and aftercooler, for engines so equipped, should be inspected and rebuilt at this interval.

A major engine overhaul involves disassembling and inspecting the engine block and replacing piston rings, cylinder liners, crankshaft bearings and seals. Some manufacturers recommend a major overhaul after 24,000-30,000 full-load hours.

The actual need for engine overhauls depends on the specific engine and the quality of the preventative maintenance program. Power output, fuel economy, oil consumption and analysis, the results of crankcase blow-by and cylinder compression tests more accurately measure engine condition (need for major overhaul etc).

Service Contracts
Service contracts are available from the engine manufacturer. These contracts can be written to cover all service procedures, including routine maintenance, inspections and oil changes or just engine overhauls. A service contract is highly recommended at the time of purchase to insure the engine is properly maintained for performance and long life.

The cost of a service contract varies with the level of service and specific type and manufacturer of engine. The cost is normally based on the engine horsepower rating and EFLH. In general, the cost of a comprehensive service contract usually runs between $.01-.02/Hp/Hr depending on the specific type and manufacturer of engine. This cost is minimal compared to the potential savings of engine driven equipment and is usually offset by the recoverable waste heat from the engine jacket.