The long hours and hot weather of summer are the ultimate tes equipment. Maintenance managers with the best springtime preparation stand the greatest chance of making it through the summer season with maximum uptime. Telling you that when autumn is here might seem akin to shutting the barn door after the horses have fled. However, winter is almost upon us and that means spring isn’t far behind. So if you can spare a minute or two, it might be interesting to compare your springtime maintenance procedure with my own. Service engineers stress five important factors related to fuel consumption in hot-weather operation of heavy equipment:
* maintaining a proper air/fuel mixture into the engine;
* assuring an adequate supply of clean air to the engine;
* maintaining the cooling system for proper operating temperature;
* using high-quality No. 2 diesel fuel; and
* setting hydraulic pressures at specified levels.
A pressure test of the air induction system will help prevent the entry of foreign materials into the engine, and a thorough diagnostic test of the engine will ensure proper engine performance and continual logging of guideline data readings, thus measuring engine wear condition. Most equipment manufacturers recommend that these tests be done at least once a year.
Actually, spring is the ideal time to be sure the engine is in top operating condition. It can then keep going all summer and develop maximum power per gallon of fuel consumed. Fuel is purchased by the gallon, but burned by the pound to produce horsepower. Engine diagnostic procedures include tests for intake manifold pressure, crankcase pressure, air cleaner restriction and power output at stall speed. At stall, the smoke level should be observed. Excessive smoking when the filters re known to be clean indicates the fuel-air ratio is out of balance. Nozzles should be checked or serviced and the injection pump tested.
Maintaining the integrity of the air induction system is an important factor for best utilization of fuel and maximuu engine life. Most people familiar with diesel engines realize the great amount of air that must be taken into the engine for proper combustion. Yet, the high compression ratios and close tolerances of these engines require elimination of the most minute particles to prevent abrasion and potential destruction of internal engine surfaces.
This places a tremendous burden on the air intake and its filtering system. This is especially true during dirty, dusty summer operation, when running under heavy loads at maximum horsepower output requires maximum air intake. Loose clamps, tiny cracks in the hose or piping, poorly connected slip joints, or defective seals must be repaired quickly to prevent unfiltered air from entering the engine.
Most manufacturers of heavy-duty equipment carefully test the air induction systems of new engines, and some manufacturers have developed pressure tests for distributors to perform during pre-delivery or when diagnosing service problems. Air systems should be checked in this way once a year or after every 1,000 hours of operation and any time air systems are disassembled for repair or replacement.
Again, the weeks in early spring are an excellent time to assure the integrity of the air intake system of your diesel engine, to prevent unnecessary downtime later. Of prime concern on turbo-charged units are the connections at the suction side of the air cleaner, the turbo-charger, and the air-compressor. On naturally aspirated engines, the most important components are any connections between the air-cleaner and the intake manifold.
Special attention should be given to the air-cleaner itself. Check nuts and threads for condition and tightness, and make sure gaskets and seals are in good condition and not sticky. If the paper element is damaged, dented or deformed in any way, replace it with an element recommended by the manufacturer of that machine. The inside of the cleaners themselves should be thoroughly wiped clean prior to element replacement.It is a good idea to go into the summer season with fresh air-cleaner elements.
The cooling system should also be a concern, both for fuel conservation and for assuring proper cooling to the engine during high-load operation in hot weather. Be sure specified radiator pressure for your machine is maintained. Check the pressure cap for proper pressure relief. Check the radiator and all hose connections for leaks.
Hoses should be examined, and if a soft, cracked hose is found, remove it and check the inside for splitting, softening or swelling, which could cause a restriction. If one bad hose is found, it is a good idea to re-hose the entire machine because the others are probably in similar condition. At the same time, installing heavy-duty hose clamps and the latest style and material of hoses will provide additional protection to the cooling system.
The radiator should be checked for leakage and repaired if necessary. The condition of fan belts should also be checked. If one belt is bad, replace both belts. Belt tension should be adjusted to manufacturers’ specifications because a loose belt will wear the pulley and belt rapidly. A tight belt will cause excessive belt wear and ultimate failure to the alternator, water pump or idler bearings. On older machines, check the belt pulleys for wear. If the belts are riding low (low profile in pulley groove), consider replacing the pulleys.
Don’t forget to re-index the fan for summer operation if it is reversible. Or, if you replaced a blower fan with a sucker fan for the winter, be sure to change back to the blower. Your operator will appreciate it.
The coolant deserves special attention because it is the medium for transferring the high heat of the engine to the radiator for dissipation to the air. Coolant is especially important in modern, small, high-horsepower diesel engines equipped with wet cylinder sleeves. Vibration causes cavitation and erosion along the outside of the wet sleeve, which in turn causes pitting and early failure of the sleeve. Without proper inhibitors in the coolant, erosion of these sleeves can destroy an otherwise fairly new engine.
The maximum amount of additives in antifreeze used in today’s engines is sufficient only to handle rust and scale build-up within the cooling system. Antifreeze alone won’t protect the wet cylinder sleeves in either on- or off-highway equipment. An additional coolant conditioner must be used.
Manufacturers now employ a water filter conditioner attachment as standard equipment on their wet sleeved diesel engines. The filter has a spin-on element similar to an oil filter. It removes solid particles from the coolant. Blocks of chemical additive are also contained in the element and this works in a way similar to an oil filter. Solid particles are removed from the coolant. Blocks of chemical additive are also contained in the element, and they dissolve quickly to recharge the system after a new element is installed. Every manufacturer recommends a certain frequency for changing the water filter element and conditioner.
Machines without this attachment can be equipped with one, or liquid conditioner can be added. The importance of keeping the cooling system of wet cylinder sleeve engines charged with water conditioner cannot be overemphasized. An engine can operate without antifreeze, but plain water is never to be used without a recommended water conditioner or additive.
To save money on fuel costs, a good grade of No. 2 diesel fuel should be used. Fuel with a high British Thermal Unit (BTU) content has more power per gallon t tn fuel with a low BTU content.
Since today’s fuels often move quickly from refinery to user, residual water from the refining process has little time to settle out of suspension, and this water can be troublesome. In warm weather, some percentage of it will pass through the fuel filter and into the injection pump, where it can cause corrosion of the close-fitting parts and shorten component life. Some heavy equipment servicemen are installing pre-filters or units
to trap excess water if they suspect fuel has a high water content.
Fuel efficiency will be adversely affected if the hydraulic control valves are set to produce pressures above the manufacturer’s recommendations. More of the power produced will be taken away by the hydraulic system and less will be available to move the machine. Therefore, adhering to the recommended hydraulic pressure settings is advised for best fuel efficiency.
Most manufacturers of heavy equipment estimate that as much as 80% of all engine failures can be attributed to contamination within the close working parts of the engine. This contamination can enter the engine in a variety of ways, the most common of which is through fuel, air or motor oil. That is why manufacturers place such great emphasis on maintaining the integrity of the air induction and fuel systems. Filters, which are key parts of those systems, should be replaced at recommended intervals. Money spent on filtering out contaminants is a small price compared to the cost of an engine overhaul.
Using non-OEM-filters not specifically tailored for the engine represents a compromise. They probably do not offer the total protection required, so buying less expensive filters may be uneconomic, particularly when getting equipment ready means long hours of heavy usage with minimal fuel expense and no anticipated downtime.
No one wants to have a machine down for a major repair during the busy season. A thorough spring servicing of your vehicles is worthwhile preventive maintenance. It will establish a feeling of confidence for owners and contractors that their machines will survive the summer without major problems.
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