Drive Systems: Considerations with Engine Applications - Maintenance
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.
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.
operating time interval for major overhauls varies considerably, depending on
the engine model and its manufacturer as well as on lubrication and maintenance.
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.
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.
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 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.
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