LUBRICATION IS A COMPLEX STUDY

Press, Volume CI, Issue 29749, 16 February 1962, Page 12

LUBRICATION IS A COMPLEX STUDY

Conclusion

THE earlier. comparatively simple types of lubricant deteriorated with use, but improved refining processes produced satisfactory results for the cars of the 1920’s and 1930’5. However, still further improvements in engine design, making additional demands on the lubricant, created more problems, and to meet them the highly refined base oils were fortified by special chemical compounds known as additives. These additives are selected for various special requirements. Some improve the viscosity; some prevent oxidation and consequent corrasion; others are detergent additives which prevent carbon, and sludge deposits. Most of this research is done in the laboratory, but a comprehensive road testing programme is also carried out. New production cars are examined and lubricants tested in them to ensure that they perform satisfactorily. From time to time, fleets of cars are driven under different climatic conditions in various parts of the world, and careful analyses made of the way in which particular oils stand up to these tests. Many of the tests can be simulated under laboratory conditions, but it is considered that more accurate results are obtained in the field. Farm Use Another wide use of lubricants in the automotive field is for farm tractors, which operate under particularly arduous conditions. Several companies have produced a grade of tractor oil which can be used not only for the crankcase, the transmission and the hydraulic system, but in summer and winter as well. At one time, a farmer had to keep many kinds of oil for his tractor—different grades according to season, different oils for engine, transmission, hydraulics and so on. Now one oil has been developed to meet all these requirements.

The use of lubricants in industry covers the widest possible range, from dentists' drills to power stations. In many cases, the lubricant has to be specially tailored to suit individual requirements.

This means that in a large factory, many different lubricants have to be stocked. Although there have been cases where up to 150 grades are necessary, in most cases by rationalisation of the grades in use, it is possible to reduce considerably the number required.

In this field, as with tractor oils, a great deal of research is being carried out to try and reduce the necessity for having so many different grades by making one lubricant do the work of several. Availability One of the major problems in marketing lubricants internationally is that cars and machinery manufactured in one country are exported all aver the world, and therefore suitable lubricants have to be made available wherever the machinery goes. Part of most companies’ research programmes is to test new engines and new mechanical equipment and find suitable lubricants for them. These are then demonstrated to the manufacturer in order to obtain an official recommendation, which means that the brand of oil is listed in the manufacturer’s handbook.

The third main category for the use of lubricants is in the marine field, generally less known perhaps but certainly one of the most important.

The machinery in a ship for which marine lubricants are provided ranges from the main engine down to the smallest motors in electric fans and even the galley dough mixer. The lubrication of the cylinders of large diesel engines burning heavy fuel is of particular importance to a shipowner. Such a lubricant not only protects the cylinder liner from corrosion but reduces the rate of wear and keeps piston rings free. Thus, it extends the period of time between engine overhauls, saving the expense of more frequent maintenance and increasing the earning capacity of the vessel. Other lubricants in the form of heavy oils or greases protect the deck machinery, such as winches boat davits and wire from the corrosive action of salt waiter.

Before a on marine lubricant is the market, it W tested during full scale ser vice trials at sometimes take a y ear more before aU the information on ance is obtained. These teste are often conducted on aw® of the company» tanker fleet. Automotive

For cars, a very wide range of oils and greases are required. Large numbers of different grades of_ required for different. gearboxes and differential units.

Hydraulic brake systems, clutch systems, power steering and automatic transmissions all require or fluids. Mineral oils, however, are never used in most hydraulic systems as they rot hoses and cups. Mineral oils such as petrol, kerosene, or lubricating oils will cause considerable damage to braking systems, and their use will generally result in brake failure. Very small traces can cause damage and brake fluid should not'be stored in a container which has held oil. or poured through a funnel which has been used for kerosene or petrol. Hypoid Modern differential units in particular require high pressure oils because of their hypoid gear consruction. The gear teeth in this type of differential have a wiping action when they touch each other, and this requires a very different lubricant from that used, for instance, in the crankcase. In some cars several different types of chassis grease are often specified, although most oil companies have now developed general purpose greases for chassis lubrication. Different grades of oil are used for lubricating door hinges and various linkages and there are special anti-cor-

rosive oils, miscible with water, which are tised in cooling systems. Efficiency . The efficiency of the oil in the crankcase is very important tv the life of the engine. In addition to lubricating, by providing a cushion of oil between bearing surfaces, the oil must cool and clean. Oil which, when drained from the crankcase after some time, is perfectly clear is usually not doing its job. If the oil is dirty, it shows it is cleaning the engine of carbon particles, sludge and contaminants. The oil should always be drained after the car has been on a run, as the oil will then be well agitated and will carry dirt and foreign bodies out with ft. If it is drained after the car has been standing for some • time the dirt will be left lying on the bottom of the crankcase. If a car is used mainly for short runs, particularly if i ttey are done in cold weather. , the oil should be drained I frequently. : On short runs the oil never heats up properly, and water and petrol in it does not evaporate. The water will in time form a black sticky sludge which can block oil galleries. i and it will also dilute the oil . and reduce its efficiency. In - time gums and varnishes . which may cause damage also > form. ’ Additives and refining pro- ' cesses developed through re- ‘ cent research by oil compan- ' ies have made their products ' much more resistant to the formation of gums and . sludges than in former years. J Modern design of engines , and oil filters has also made ; oil changes necessary at less frequent intervals, but an engine in which the oil is > changed regularly will r always last longer and run 5 better than one which is ser- - viced only infrequently.