Harold Whiting Slauson

“ Magnetos The perfection of the magneto and its application to cars of all classes and sizes has marked the most important step in gasoline motor ignition since the introduction of the electric spark. The magneto is now considered one of the most vital parts of the car, and while it is possible for the motor to be run for many miles on the batteries that form the auxiliary ignition sources, the mechanical current generator has left the field of the desirable accessories and has become an actual, physical portion of the engine. ”

“ Whenever the radiator will accommodate a couple of quarts, or more, it is well to fill it, for too much water cannot be used on the modern design of cooling system. It is true that a motor runs at its highest efficiency when its temperature is as great as that at which proper lubrication of the pistons can be obtained—for a gasoline engine is a "heat engine," and the greater its unnecessary heat losses, the less will be the power developed by it. But a motor cannot be kept at the proper temperature by reducing the amount of cooling water in its circulating system. ”

“ In view of the difficulty which has been experienced by many drivers in sufficiently lubricating the pistons without causing the car to emit clouds of smoke, it may well be asked, "Why cannot an unburnable oil be used and thereby eliminate this trouble?" This is out of the question, for the mineral oils now used are obtained from petroleum and are cousins of kerosene, gasoline, benzine, and many of the other highly-inflammable liquids that need but the touch of a match to burn almost with the rapidity of an explosion. ”

“ In the Diesel motor, on the other hand, the ignition continues as long as fuel is admitted, and thus this engine is of the internal combustion type in the strictest sense of the word. It is, after all, the expansion of the gases due to the heat of combustion that produces the power in a gasoline engine, and if the fuel can be so admitted that it can burn during the greater part of the stroke, a high efficiency will be obtained. ”

“ If the reader remembers that it is but one hundred and ten volts that is used to operate our electric lights and that five hundred will run a trolley car, he may wonder why it is not dangerous to handle as great a pressure as the thirty thousand volts that are used in connection with the ignition system of a motor car. ”

“ But even though the explosion in a four-cycle motor occurs only every other revolution, the engine is by no means idle during the interval between these power impulses, for each stroke has its own work to do. The explosion exerts a force similar to a "hammer blow" of several tons on the piston, and the latter is pushed down, thus forming the first stroke of the cycle. The momentum of the flywheel carries the piston back again to the top of its travel, and during this second stroke all of the burned, or exhaust, gases are forced out and the cylinder is cleaned, or "scavenged." ”

“ In order that the motor car power plant shall be light in weight and occupy but a small amount of space, the power must be transmitted at high speeds. In many an automobile motor, the pressure imparted to a single bearing during a certain portion of its revolution may frequently be well over two tons, and in this same bearing, the "speed of rubbing" may approach eight or nine hundred feet per minute. In other words, at normal speeds of the motor, about a sixth of a mile of steel surface will rub over a certain point in each crank shaft bearing during every minute that the engine is running. ”

“ It is well known that a "high-test" gasoline, such as a 76, will vaporize more easily than will one of a lower degree of specific gravity. Also, every motorist has had impressed upon him the fact that heat aids in the vaporization of gasoline. If we try to start a motor on a cold morning with a low-grade gasoline, such as the 60- or 62-degree fuel now generally obtained, we know that a rag dipped in hot water and wound around the carburetor will help matters. ”

“ In view of the marked difference in the results obtained from the use of mixtures that are "just right," and those which vary but a slight percentage in the proportion of gasoline vapor to air, it may be well to examine, superficially, the effects of "rich" and "weak" charges, and therefrom to obtain a list of "symptoms" which may aid us to diagnose motor trouble properly.
We all know that air—or oxygen—is required to support combustion. "Snuffing" a candle is merely covering its end so that air cannot reach the flame. ”

“ Water in the fuel is an annoyance that is often encountered by the automobilist and the motor boatman, and this will make its presence known by causing the motor to skip when all adjustments and connections seem to be in perfect condition. Water is much heavier than gasoline and has no affinity for it, and consequently, as it sinks to the bottom of the tank, a few drops in a large amount of gasoline will cause trouble by passing out through the needle valve at intermittent intervals and forming an unexplosive mixture. ”

“ The Ignition System It was the application of the electric current to the ignition system of the gasoline engine that first enabled these new forms of power plants to be designed with sufficient compactness and to possess enough flexibility to render their use practical on self-propelled vehicles. Without the electric ignition system, the speed and power of the vehicle could not well be controlled, and the explosions would be uncertain and irregular, at best. ”

“ One such two-cycle motor that has been designed especially for automobile use employs a separate air compressor driven by the engine itself and used as the clutch and variable speed transmission of the car. The amount of pressure generated in the compressor is dependent upon the resistance offered to its operation—or, in other words, it increases with additional load carried by the motor. The compression, or compressed air, rather, is carried directly from the compressor to the cylinders of the motor, being admitted at the proper time by a rotary valve driven by the crank shaft. ”

“ Just when this type of motor will be taken up by automobile designers is difficult to state. The Diesel type of engine has proved so wonderfully successful for large stationary power plants and for marine purposes, and its reliability is so absolute on all grades of fuel, that this motor may solve the failing-gasoline-supply problem. As yet, about 100 horsepower is the smallest unit that has been made in any quantities, but it was recently announced that this type would, in the very near future, be built for motor trucks and other commercial vehicles. ”

“ Types Of Motors There are certain events that must happen in a gasoline motor before the engine will run of its own accord. For instance, to obtain successive power impulses, the charge must first be admitted to the cylinder and compressed; it must then be ignited to form the explosion that creates the force at the flywheel ”

“ Although, of small volume, such a spark generates intense heat, and it is upon this quality, rather than upon area, that the charge depends for its ignition—although it is claimed that a large flame will produce more complete, rapid, and consequently more efficient, combustion. But the jump spark possesses the advantage of requiring no moving parts projecting through the cylinder walls into the combustion chamber, and its greater simplicity over that of the make-and-break system has resulted in its almost universal adoption by automobile manufacturers. ”

“ Numerous cases are on record in which cylinder heads have been blown off or castings cracked by the force of some of the explosions when too much "dope" has found its way into the mixture.
Although the average motor gasoline obtainable nowadays is hardly all that could be desired as automobile fuel, a little care taken when filling the tank will eliminate many of the carburetor annoyances to which many cars seem to be subject. ”

“ Therefore, in winter, a thinner oil was required than in summer, for the more a lubricant is warmed, the thinner does it become—and vice versa. With the mechanical force systems now in use, however, practically the same kind of oil may be used throughout the year—although many motorists believe that better results will be obtained if a heavier oil is used in summer than in winter. The oil will be warmed by the motor and it will not require many minutes of operation before a lubricant made thick by a low temperature will flow freely and do its work as efficiently as a thinner oil. ”

“ If the owner would satisfy himself that the cylinders are receiving a sufficient amount of oil, he may open the individual pet cock on each, and if he finds there a faint blue trail of smoke at each explosion in that cylinder, he may rest assured that harmony exists between the rubbing surfaces of the piston and the cylinder walls. ”

“ The practice of "doping" the fuel tank by adding to the gasoline ether or some other highly volatile liquid is not to be recommended to the average motorist. A few ounces of ether or chloroform added to the fuel will form a more volatile and consequently more powerful mixture, but unless the greatest care is taken, the motor is liable to be completely ruined by such a procedure. ”

“ Even when ignition does take place, the resulting power impulse will be weak because of the comparatively small amount of pressure-producing gas in the mixture. The explosions may occur regularly for a while, but there will be a marked decrease in the power developed by the motor, and owing to the fact that weak mixtures may be slow-burning, "back-firing" will often result in some engines to which such a charge has been fed. ”

“ The expert will judge of the condition of a motor by the wear that has occurred in the bearings rather than by any exhibition of temporary power that it may develop in a short test, and it is for this reason that the "general public" runs a risk whenever it buys a second-hand car that has not been thoroughly overhauled by a reputable factory or inspected by a competent engineer. ”

“ Carburetors And Their Fuel Although gasoline is inflammable in its liquid state, its combustion is not sufficiently rapid to approach the explosive point necessary to render its energy available in the automobile engine cylinder. The proper proportion of gasoline vapor and air, however, forms a mixture that is highly inflammable and that will be entirely consumed in the engine cylinder under ordinary conditions within about one-twentieth of a second after the formation of the spark. ”

“ In other words, there is an explosion in each cylinder of the two-cycle motor with every revolution of the flywheel,—instead of with alternate revolutions, as is the case with the four-cycle type. But the number of events necessary to produce each explosion must be the same in both types of motors, and consequently it is only by "doubling up" and performing several operations with each stroke that the two-cycle motor can obtain a power impulse with each revolution of the flywheel. ”

“ It is evident that, beyond a certain size of cylinder, a bloc casting becomes too bulky to be handled conveniently, and as the entire casting must be removed when it is desired to reach the connecting rods, crank shaft, or piston rings, a motor so designed will seldom be found that develops more than forty or fifty horsepower. ”

“ But even between the best-lubricated surfaces, employing the most efficient metal as a bearing, some wear is bound to occur. The crank shaft of a four- or a six-cylinder motor is forged or sawed from one piece of steel, and with the accurate machining, finishing, and grinding to which it is subjected, it becomes an expensive part of the engine. ”

“ The coil and batteries or magneto by no means form the entire ignition system, although the generation of the spark depends entirely upon them. The spark must be regulated to occur at the proper point in the stroke of the piston, as a continuous spark would not only waste the current, but would cause the ignition of the charge during the upward stroke and would result in an impulse in the reverse direction that would prevent the motor from running for more than half a turn. ”

“ A clogged gasoline pipe or dirty strainer will produce the same effect on the operation of the motor as will a float that is set too low on its stem. When the motor seems to starve at high speed, and it is evident that there is sufficient gasoline in the tank, the union should be disconnected at the point where the feed pipe joins the carburetor. ”

“ The modern carburetor is sufficiently automatic in its action to provide the proper mixture within wide ranges of speed change of the motor, but even nowadays it is often found necessary to increase the gasoline supply or to reduce the amount of air admitted to the intake pipe whenever it is desired to throttle the motor down to a very low number of revolutions per minute. ”

“ Therefore such surfaces as the cams or valve stem rollers will demand less oil than will the bearings revolving at higher speed and carrying heavier loads. But it is the hardest-worked bearings that form the majority of the friction surfaces of a motor, as will be realized when it is remembered that all points on the circumference of a three-inch crank shaft bearing will travel at the approximate rate of 1,000 feet per minute—and these are the portions that also carry the heaviest load. ”