COIL IGNITION

Rotorua Morning Post, Volume 2, Issue 314, 30 August 1932, Page 2

COIL IGNITION

USEFUL POINTS i i CARE AND MAINTENANCE WILL ENSURE SATISFACTORY RUNNING. It is interesting to note that coil ignition was the earliest electrical means of producing the spark in the combustion chamber, and its total eclipse and subsequent return to favour in without counterpart in the development of the motor car, states an article in The Morris Owner. i Contrary to general accepted ideas, coil ignition is actually simpler than a magneto. Moreover, if any thing does go wrong, everything is readily accessible and no particulav mechauical skill is, demanded in rectifyirg matters. The reason for its return is simple; all cars now have a large capacity accumulator on board for lighting purposes, and the almost negligible amount of current which coil , ignition demands even for a six-cylin- J der car. Indeed, while there is a mere glim- j mer in the headlamps from the ac- ; cumulator, there will be sufiicient cur- j rent from the battery to ensure a ready start (although, of course, in such an event the starting handle wonld have to be used), and as the quality of the spark is not degenpent on the speed with which th'e engine is revolved, starting is definitely easier than in the case of the magneto. A Simple System. Unless a car has been standing by for months, it is most unlikely that there would ever be insufficient current for starting purposes, and as the coil consists only of a number of turns of two gauges of wire, it means that the only thing in the circuit requiring attention, or calculated to he affected by wear oi' neglect, is the contactbreaker. This, however, can he of sturdy dimensions, with generous contact surfaces, so that it is only at widely separated intervals that even this component demands attention. Occasionally one should remove the distributor moulding and inspect the electrodes to which the high-tension cahles are secured. This is easily effected if the two securing springs are pushed aside. °Upon inspection, the electrodes should be clean and free from deposit. They should be wiped with a rag just moist with petrol, particular care being taken that the central contact is clean. If it 'should he unduly polished, it might even be prudent to scrape it very gently with a blade of a penknife. At the sama time the contact spring should be ruhbel o\cr. Keep Contacts Clean. We must be quite sure that our make-and-hreak mechanism is working ^Toperly, because upon the strength of the low-tension current depends that of the high-tension surge and consequent spark. Contact points should meet cleanly and he free from pitting, and hroken, should be the correct distance apart, which is .015in. On the littie spanner supplied with the car, a gauge of the correct clearance will he found, which may be inserted hetween the points aftir the engine has been turned into such a position that they remain open. It sometimes happens that these points become dirty, and in the case of abject neglect it is possihle that they mightmritimately reach a condition where no spark at all was induced. This state of affairs, however, always gives us preliminary warning with an elusive misfiring, and at the first signs of such misfiring, the contact brealter should he inspected and, if necessary, cleaned. Here, again, a rag dipped in petrol will serve the purpose, except in very bad cases, when it is permissible to use a nail fil'e, the finest grade emery cloth or, better still, the sides of a safety matchbox pushed down between the points. These points, he it noted, are made from a precious metal; more than two or three strokes ohviously should not be made lest it be worn away unduly. e Adjusting Points. Having finished the cleaning operations, it is, of course necessary that the whole contract breaker be wiped over with our friend the rag-moisten-ed-with-petrol, because the least littie hit of emery can do a great deal of damage. While the emery cloth is in operation, the rag, as a matter of precaution, ought to he beneath it to catch any particles of emery that may be detached. It is seldoin that the gap' at the points will require adjustment, and an owner may keep his car over a long period of years and find that it never varies from the gauge on the spanner. Should it do so, adjustment is a simple matter. The locking nut on the fixed contact is slackened off, while the other— to which the platinum point is affixed — is rotataed half a turn when the gauge is once more brought into play, and if the gap is found correct the lock nut can be tightened once more, great care heing taken of course that the adjustment is not lost. In some instances it is necessary to use two spanners, to ensure that' the screw does not turn when the lock nut is heing tightened. Push Leads Home. Care should he taken when the distributor is heing reinstated that all the wires are inserted well into their holders. Cases have been known where high'-tension cahles disturbed during cleaning operations have not been poished right home, and have been the cause of a difficulty in starting. Incidentally, leads should always he kept separated as much as possible, and a separator is standard on the car. Further, high-tension current with battery discharge caused through old leads which ane too close together can materially weaken the spark at the plugs; so much so, in fact, that it might he ' responsible for diffieult starting. It is possihle that a ear which has been unduly exposed to the sun with