Ignition, timing and valve setting

Many of the troubles from which motorists have suffered in the past - and still suffer, in fact, despite recent improvements in construction of all the essential parts of the automobile - have arisen from failure of the ignition system to perform its proper function. While these troubles may perhaps be minimized in the latest model cars, there are still in daily use in the United States and Canada many thousands of machines built and equipped in the days of motor-car development, and to every owner and operator, no matter whether his car be new or old, the subject of ignition is of the utmost importance.

To know what to do in case of ignition troubles, it is imperative to learn something definite about the principles of the ignition system used on the car. Intelligent handling of the car in emergencies can only be assured when the operator possesses such information. It will not pay to "go it blind"

I in seeking the causes of ignition failure. When the engine stops or misbehaves from such causes knowledge is indeed "power."

The object of this treatise is to equip the reader with such a knowledge of the interesting subject of Ignition that he will be able to handle his own particular apparatus with intelligence and skill. The mere consciousness that he understands the principles and construction of his ignition devices will add immensely to his comfort on the road, giving him greater confidence in himself as a driver and stripping the ignition bogey of most of its terrors.

Then, too, the very practical sections on Timing and Valve Setting will enable the intelligent reader to make all necessary adjustments of his ignition apparatus and should save many a garage bill.

All the systems of ignition in present use are described and illustrated in this work and particular attention is called to the elucidation of the magneto system - both high and low tension methods being described in detail in terms that he who runs (a motor-car) may read.

One of the subjects of primary importance to the automobile owner or operator is that of Ignition, or the means employed to produce the combustion of the gasoline "mixture" in the motor cylinder or cylinders. It is altogether desirable, if not essential, that the motorist should acquire a knowledge of this subject very early in his automobile career and the various methods of ignition employed in modern motor-car practice are here presented in such a manner as to be readily understood, even though the reader has but a smattering of knowledge of the principles of electricity. A careful study of the ignition system used on any particular car is recommended to the owner and operator, and such study will surely be repaid in added comfort of travel and avoidance of ignition troubles.

Whatever may be the system employed on his car, the reader will find in the following pages many valuable hints for his guidance in emergencies. One cannot know too much about the subjects treated.

Ignition - The act of igniting, kindling or setting on fire; also, a means of igniting. A term applied broadly to the apparatus necessary for the ignition of the explosive gases in. an internal combustion engine.

Ignition methods may be primarily divided into two systems electrical ignition and incandescent ignition. So far as the purpose of the motorist goes, the incandescent ignition may be practically left cut of consideration. The type of incandescent or catalytic ignition in which a spongy platinum plug is caused to glow or become incandescent under the influence of compressed gas has been experimented with by many, and in the future may provide some measure of success. At present it would appear that the difficulty of accurately timing the explosion is one which has not been overcome, and, until it is, the system may be put out of court as an efficient method for firing a car engine. We are, consequently, left with practically only one broad principle of ignition, that is by electric spark or sparks ; but the multitude of means by which this spark can be produced and regulated makes the question very much wider and more complicated than it would at first sight appear.

Before commencing the study of any of the different systems of ignition it will simplify the matter in the mind of the reader to grasp first the requirements of the internal combustion engine in the matter of the ignition. The cycle of operations inside an engine being understood, it will be seen that the first and most important requirement is that the spark for igniting the charge should take place at a predetermined and easily regulated time relatively to the position of the piston in the cylinder. It being one of the requirements of the internal combustion engine, as made to-day, that the gas charge should be compressed in the cylinder, it is obvious that to get the best results it should also be exploded at the time when it is most fully compressed. This time, of course, is the time when the piston has reached the top of its stroke and is commencing to descend. The greater the delay in the generation of the spark after that point has been reached the less will be the power generated by the explosion, not only because the piston has traveled part of its course, but also because for every fraction of an inch it moves downward the compression of the gas charge is being reduced. It is clear then that as well as the electric spark and the method of producing it, we must have some method of regulating the time at which it shall take place.

Putting aside the question as to the production of the electric energy required, it will be seen that we not only require apparatus for its production, but we also require mechanical means for the adjustment of the time at which it should operate. This applies to every type of electrical ignition, and no matter what the source of the electric current may be, there must be this mechanical timing apparatus working in conjunction with the engine and capable of being adjusted.

As to the method of its operation we may take an imaginary case of the simplest form of ignition which it would be possible to use. Consider it as consisting of some source of electric energy, such as a dry battery, some means of conducting the electric current to the inside of the cylinder where the explosion is to take place, and some means of causing it there to give an electric spark hot enough to ignite the gas. If our source of electricity were capable of giving us sufficient voltage and current, we might very easily arrange an electrical system which would consist of a couple of insulated wires leading from the source of supply, and, inside the cylinder, some method of causing the ends of these wires to come in contact and allow the electric current to flow, and then, at the time the ignition should take place, to separate themselves by some mechanical movement operated by the engine itself. It is an electrical phenomenon that when an insulated path conducting a current is suddenly broken a spark will pass between the interrupted ends.

While a system operated on these simple lines really covers the whole ground, yet the actual difficulties to be overcome in applying it to an internal combustion engine, as well as the fact that in its simplest form it would be wasteful, render the adoption of more complicated methods necessary. In the first place, the arrangement of a mechanical contact breaker inside the engine introduces difficulties not easily overcome. In the second place, the nature of the current given out by a dry battery is not the most suitable for this particular work. These difficulties have resulted in the adoption of numerous systems, underlying all of which, however, this fundamental principle will be found. We can divide the systems roughly into two classes, depending on the method of producing the electric energy.

In one case the electric energy is produced by the chemical action taking place between two dissimilar metals or com- pounds under the influence of an acid or salt; in the other it is obtained from a mechanical appliance provided with permanent magnets, the magnetism of which can be used, under suitable conditions, to produce or induce a flow of electric current; that is to say, the magnetism of the permanent magnets can be turned into electric energy.

The first method uses a dry battery or an accumulator, both being chemical appliances - the first a prime source of electric energy, and the second a storage appliance for electricity produced by any of the known methods and commonly called a storage battery. In the second division the source of power is a magnetic dynamo, usually known as a magneto, and this is driven by the engine. The source of electric energy is thus made part and parcel of the mechanical plant of the car, and independent of any outside source of supply.

The electric system of ignition by magneto is again subdivided into two classes depending on the nature of the current which the machine gives out, about which we shall have something to say further on, but they may be classified here as Low Tension and High Tension. These three sources of current supply - that is, the dry battery or storage battery, the high tension magneto and the low tension magneto, practically cover the entire field, but their application is varied indefinitely, and combinations of any two, or even three, systems are sometimes to be found in one motor.


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Ignition, timing and valve setting