Spark plug

“ The spark plugs, though used, are nevertheless Champion plugs and not those of another make. [5] There is evidence to support what one would suspect, that a used spark plug which has been repaired or reconditioned does not measure up to the specifications of a new one. ”

“ If no spark passes when the timer makes contact, the trouble is in either the wire or the coil; if a spark shows, it should be of good strength, for a current that will produce a fair spark in the open may not have sufficient strength to produce a like result when under compression. If a good spark shows, the spark plug may be suspected of being fouled and thus short-circuited, of having a breakdown in its insulation, or of there being too great a distance between its points. ”

“ A good plug properly constructed should outlast the life of the motor. When purchasing new plugs, first examine the old plug and get one of the same length. This is very important as spark plugs are made in as many different lengths as required by high and low compression motors. High compression motors have a small low walled combustion chamber, while low compression motors usually have a spacious high wall chamber and require a longer plug, whereas if the long plug is used in the high compression motor it may be put out of commission by the ascending piston. ”

“ If, with an apparently good spark, you have compression and there is mixture passing into the cylinders, the trouble may be in the spark plug. To test a spark plug it is necessary to remove it. Widen the gap to 1⁄8 inch and lay the plug with wire attached upon the cylinder; crank the engine and see if a spark jumps the gap. Widening the gap is necessary because the spark will not jump so far under compression as in the open air. If it does not jump, the plug may have a broken insulator porcelain or need cleaning. ”

“ The first thing to do is to loosen one of the wires from a spark plug and lay it so the bare end will be 1⁄8 inch from the base of the plug, and have someone crank the engine by hand or with the starter. If a spark does not occur, go first to the interrupter points and short circuit the fixed point with a screw driver or other metal tool and see if there is a spark when the engine is cranked. ”

“ It is hard to obtain absolutely perfect insulation; for the terminals deteriorate as they become overheated, break, or become foul (Fig. 13) . In oil-engines, especially, soot is rapidly deposited on the terminals, so that no spark can be produced. In benzine or naphtha motors, such an accident is less likely to happen. In automobile-motors, however, the spark-plug only too often fails to perform its function. The one remedy for these evils is to be found [33] in the most painstaking care of the spark-plug and of the other elements of the ignition system.
Fig. 14.—Magneto ignition apparatus. ”

“ The electrician held out an instrument resembling the spark plug of an automobile. "This is all we need. I've connected a dead wire in the loading room to this switch. If the plant is to be blown up, all that will be necessary will be for me to put this plug in a light socket in that room, then come back here and throw the switch. The minute the switch is thrown a streak of fire will shoot out from the spark plug. It will ignite the explosive dust with which the room is filled. The factory will be blown to pieces." ”

“ If the electrodes or spark points are dirty they should be cleaned with fine sand paper, special attention being paid to the surfaces from which the spark issues. When reassembling the plug, see that all of the washers and gaskets are replaced and that the length of the spark gap is unchanged. A little change in the spark gap may make a great change in the spark. A good spark is blue white with a faint reddish flame surrounding it. When the discharge is intermittent or sputters in all directions, either the coil or the plug are partially short circuited. Always have a spare plug on hand. ”

“ When the primary current is at its maximum and its circuit is broken, another condition exists, for then the secondary distributor is making contact, the only gap being in the spark plug, but the sudden demagnetization of the armature core as the primary circuit is broken, and the additional effect as the armature passes the vertical position, induces in the secondary winding a current of great intensity that passes to the spark plug by way of the distributor, returning to the winding by the ground. ”

“ The ignition system is the name applied to the batteries, coils, commutator and spark plug which, acting as a whole, produce an electric spark hot enough and at the right time to fire the charge in the cylinder. There are three ways in which an electric current may be obtained which have been found to be of practical use in automobile construction. ”

“ The current from a high-tension magneto is of such intensity that the small points of an ordinary spark plug would quickly be burned, and it is necessary to provide plugs with heavy points, which will stand the work. ”

“ I began to crank, praying steadily for a miracle. Now and then I managed to coax forth a gaseous chortle or two. The convention on the landing understood every chortle in a truly marvellous way.
"It's the spark-plug, that's sure!" announced one with an air of finality. "When an engine has run for a while (!) the spark-plug gets all smutted up. Have you cleaned your spark-plug?" ”

“ When the vibrators are not properly adjusted more current is required to make and break the contact between the points, and, as a result, at cranking speeds you would not get a spark between the spark plug points. ”

“ Although only called upon to jump a gap about a sixteenth of an inch across, the ordinary high-tension current is capable of bridging a space eight or ten times this width in order that ample pressure will always be assured for the formation of the spark. Furthermore, the warm gases in which the spark is formed in the cylinder increase the resistance ordinarily encountered and it is consequently necessary to raise the voltage above the amount that would be needed were the plug exposed to the open air. ”

“ The induction-coil is fitted with a trembler or interrupter, which easily gets out of order and which must be regulated with considerable accuracy. The spark-plug is a particularly delicate part, subject to many possible accidents. The porcelain of which it is made is liable to crack. ”

“ A high tension spark occurs at each contact of the roller with the sectors, as the contact allows current to flow through the primary of the coils. The high tension 238binding posts S1-S2-S3-S4 are connected with the spark plugs or spark gaps U1-U2-U3-U4 by means of high tension cables. As soon as the timer grounds a coil, the coil produces a high tension spark in its corresponding spark plug. ”

“ The space filled with air or other dielectric between high potential terminals (as of an electrostatic machine, induction coil, or condenser) , through which the discharge passes; the air gap of a jump spark.
Spark plug. In internal-combustion engines with electric ignition, a plug, screwed into the cylinder head, having through it an insulated wire which is connected with the induction coil or magneto circuit on the outside, and forms, with another terminal on the base of the plug, a spark gap inside the cylinder. ”

“ The ignition system differs from that of the conventional automotive types in that it has no distributor. A circuit breaker alone is used. Both coil high‐tension winding ends lead directly to both spark plugs. Thus both plugs spark at the same time, one cylinder being on compression stroke while the other cylinder is on exhaust stroke.
83. SPARK PLUGS. a. Defective spark plugs are indicated by engine missing, overheating, knocking excessively, and lacking normal power. ”

“ It is no more than a restoration, so far as possible, of their original condition. The type marks attached by the manufacturer are determined by the use to which the plug is to be put. But the thread size and size of the cylinder hole into which the plug is fitted are not affected by the reconditioning. The heat range also has relevance to the type marks. And there is evidence that the reconditioned plugs are inferior so far as heat range and other qualities are concerned. But inferiority is expected in most second-hand articles. Indeed, they generally cost the customer less. ”

“ While turning, watch the spark between the two points. If it is feeble the adjustment is not correct, the screw is either tight or too loose. After a few attempts you will be able to adjust very quickly and almost unerringly.
See that the points are kept free from oil.
Loose terminals.—The car may run badly on account of a loose terminal of the wires on the sparking-plug or battery. This is simply a matter of thoroughly tightening up the various little nuts with a spanner. ”

“ Another perennial problem was spark plugs. It was almost incredible how sensitive such little things could be. One might think that the manufacturers should long ago have discovered all the secrets of such a simple device, and reduced the product to some degree of standardization. But everything in aviation was so high-strung, every device so sensitive, it seemed that just changing one minor dimension of a standard nut or bolt set in motion a whole chain reaction of troubles. Pressing always for higher power on lower weight, we created more and more troubles for ourselves. ”

“ The four-spark magneto is provided with a safety spark gap, and when the points of one of the spark plugs are separated too far, or when there is any interruption of the secondary circuit, a spark will show there. Sparks should not be permitted to pass in the safety gap for any considerable period, as damage will be done, and when they indicate by their presence that something is wrong, the trouble should be located and repaired without delay. ”

“ Sparking at the breaking contacts of an electric bell is detrimental to the platinum points, and many remedies have been devised to overcome it.
Sparking is due to the self-induction of one turn of the wire coil acting on its neighbor, and this property is utilized in the gas engine, or gas-lighting spark coil, where a fat spark is needed to ignite gas. ”

“ The veriest tyro in electrical operations knows that electricity will cause a spark, and most persons are aware that the spark possesses considerable deflagratory powers, varying with the character of the spark. In electric gas lighting a spark of the proper character is passed across a jet of gas and ignites it. Sparks can be produced by various means: friction, battery current, induction either galvanic or electro-magnetic, by a Wimshurst or Toepler Holtz machine, or an induction coil operated by a battery. ”

“ The spark might be caused by bringing the electrodes sufficiently near together at just the right moment, but the more practical and usual way is to break the current, closing it sharply by means of a lever worked by the gearing at just the moment the piston is ready to return after compressing the charge. The electric spark is by long odds the most desirable method of ignition, being safer and easier to take care of, but it requires some knowledge of electricity and electric connection to keep it always in working order. ”

“ Sparking plugs are often a source of worry, but a friend has travelled 11,000 miles and only required three plugs. Apart from an absolute fracture of the porcelain, the main cause of stoppage is owing to the plug inside the cylinder becoming fouled with carbon through an imperfect mixture being used. Often too much lubricating oil is inserted in the crank-case. This then gets over, the top of the piston and is burnt up when an explosion takes place, leaving a heavy deposit of soot. When this occurs the plug should be removed and the points cleaned. ”

“ In automobile work, where a heavy strain is made upon the engine, as in climbing heavy grades, it has been found that a stronger spark gives surer results. This would indicate more battery current through the coil, and it is a wise precaution to have a few extra cells attached that can be 40switched on if necessary.
In constructing spark coils for gas engines particular care must be given to the contact breaker. In most types of gas or oil vapor engines it is absolutely necessary to have the spark pass with uniform regularity, and immediately and surely when required. ”

“ 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. ”

“ The wire used to connect the burners is generally bare, although an insulated wire is sometimes used. But the electromotive force of a 2-inch spark is so high that it is better to run the wires so they do not come near anything liable to cause a leak. The remarkable tendency of these high-tension currents must be most carefully guarded against; indeed, it is what makes this style of gas lighting so often unsuccessful. A damp wall, gilt wall-paper, a gas pipe hidden in the plaster, will often lead off the current. ”

“ But it is only by raising the voltage of the current that even a short air gap can be bridged by the spark. In fact, a pressure of somewhat over fifty thousand volts is required to produce a spark less than an inch long in the air. ”