WATCH THE OIL

Nelson Evening Mail, Volume LVI, 4 October 1924, Page 8

WATCH THE OIL

IAI PORTA N C/E OF COR RECT LUBRICATION

ECONOMY AND EFFICIENCY EQUALLY IMPORTANT

.By ETHEL BERT FA VARY. Lnnsidtiug Engineer, Moreland -Motor

Truck Company

The question is often heard, “which is the host oil to use?” The answer iii, each condition requires a- different oil for maximum efficiency. AH the large nil'companies maintain laboratories and employ experts for producing Jit l'eienl grades of oils and studying the Conditions under which each oil gives the best results. Those experts are always ready and willing in assist purchasers in selecting the oil most suitable h>r their various purposes. Up to comparatively recently, the lubrication of engines did not receive so much attention ns now, primarily because the motor vehicle was not so refined and perfected, ami to keep the cai or truck in operation was a greater problem and of more importance. The difference in the volatility of present day' gasoline has introduced another is-sue-crankcase oil dilution: With the continuous improvement in motor vehicle construction and the ever-increasing number of' trucks and cars in operation, the elimination of waste, both as regards the amount of oil used and the cost of repair and upkeep due to'imperfect lubrication, has forced the question of “Proper Lubrication” to the fore.

ENGINE LUBRICATION To show the importance of small constructional differences in the lubrication of an engine, it might be stated that: An oil which is satisfactory, in a certain engine may be unsatisfactory in another engine where the average cylinder temperature, or the average crankcase oil. temperature, differs to some extent from that of the former. An oil most, efficient for a certain fit or clearance between piston and cylinder may be inefficient for an engine where the clearance is a few 1-1000-inch different.:

An oil excellent, for certain bearing pressures and certain speeds may not lie satisfactory for other hearing loads and other speeds. An- oil highly efficient for an engine employing pressure..lubrication may not be satisfactory for splas.h lubrication and vice versa.

Even the same engine requires a different oil ■ after it has been in use a certain lime, from that best suited for it when new, if maximum economy and efficiency are desired, on account- of the variation in clearances after the .parts are worn, and, because, when new, the 'frictional surfaces are not as smooth as after they are worn in : hence in a new machine the bearing surfaces consist ilargely of microscopic hills and hollows and consequently the. actual bearing surface is smaller and the bearing pressures larger than after they are worn smooth. It may be argued, that it is hot. practical to* stock several different oils for ;the same type of-engine ,especially by iflc.et owners who had had a number of these engines in service for various derigths of time; nevertheless, it is essential if maximum efficiency and economy arc sought.

ECONOMY IN OIL CONSUMPTION

Economy in oil consumption may not mean economy or efficiency in the operation of an engine. For instance, a thick (viscous) oil of a certain quality may show great, economy as regards oil consumption, but it. may cause considerable wear in the various parts after 5000 or 10.000 miles service, as the oil may not freely run to all the frictional surfaces, and it 'will' I 'have a higher fluid friction and thus a comparatively larger amount of power will be wasted in overcoming the engine friction losses. If the total expense at the end of one or two years were considered, another oil, perhaps thinner (less viscous), of which a larger quantity is used, may • show a- gain through a saving in repair bills and increase in power and in addition by a decrease in. gasoline consumption s on account of the better “seal” between cylinders and pistons. In another example just the reverse may hold good, i.e., a thicker oil may form a better seal, show less wear and in addition show decreased oil consumption.

CHANGING OIL CHANGES POWER

Take an actual case of a test made by the author, where a certain oil was used for two different- makes of engines one showing a much greater economy in oil ns well as in gasoline consumption. Changing to another quality of oil showed the exact opposite; the motor, which formerly was superior, was now inferior in oil and gasoline consumption and in power output. Hence we see that the problem of lubrication is quite complex and only by testing a number of different grades of oil can we determine which is the most efficient for certain engines after they have bad a certain amount of wear. Almost any oil. will do to make an engine “go,” but when efficiency and economy arc considered each condition demands a special oil.