Evening Republican, Volume 21, Number 62, Rensselaer, Jasper County, 15 March 1917 — The Motorist’s Black Plague. [ARTICLE]

The Motorist’s Black Plague.

Carbon is the '‘blaek plague of the motorist. After three or four thousand miles the lungs of even the bestdesigned motor may be so thoroughly encrusted with the black deposit that it cannot be expected to deliver Its full eciency. This incrustation interferes with the proper radiation of heat, decreases the compression space so that, premature ignitionoccurs, enters the spacer between the valves and their seats, thus causing a loss of compression and power of the explosive force, and may even curl up into points and projections which become incandescent from the heat of the motor and which thus serve as auxil.ary spark plugs, igniting the mixture long before the piston has reached Thetop of its stroke. And for this “black plague” there are relatively as many so-called “cures” on the market as for any disease afxecting the hum an anatomy. These are in the form of chemicals ard mechanical devices which may or may not .prove of benefit to the motorist, depending not only upon the individual merits but also upon the manner in which they are used. Carbon formation may be attributed to one or all of three primary causes, as follows: First, the lubricant; second, the mixture; and third, the mechanical condition of the motor. /JI lubricant contains carbon, otherwise it would not be a mineral oil. But this car bon h combined with hydrogen to form the "hydrocarbon” which is the general classification of all mineral fuels and lubricants. When combined in this -state it does no harm, as it is only when the excess carbon is freed from the oil that it will “distill” out in the form of the deposit which proves so annoying to the motorist. Some grades of oil possess a greater amount of free or uncombined carbon than others, and these, ’it would seem, would be the ones which would leave the greatest amount of carbon when they are burned in the cylinders. But the nature of this carbon residue will largely determine the amount remaining in the engine, -for if it is of the dry, powdery type it will blow out with each exhi.ust stroke, whereas if it is of the gummy, sticky kind it will accumulate on the iron surfaces and gradually harden as it is subjected to continually increasing degrees of heat. But not only should oil of the proper quality be selected, but it is important also that the lubricant should be of the correct thickness or “viscosity,”, as it is termed. A thin oil may betadapted to one type of motor having but infinitesimal clearance between the piston and cylinder walla, * heavier oil would be needed if tMs space is greater, or if the e ngine is to run at a higher decree of heat. For example, a motor having badly worn piston rings or scored cylinders, which permit a thin oil to pass by the piston, would smoke bau .y if the grade suitable tb that motor when new were employed. In this case, a heavier oil than that recom mended should be used to overcome thf mechanical defects- of the worn motor. The proper mixture to be supplied tb the cylinders is also an import am consideration in c vercoming the car bon ayil.—Leslie’s.