How To Drive A Motorcar
A Key To The Subtleties Of Motoring

HOW TO DRIVE A MOTORCAR look round at all the wires to see that the terminals are right, the connections good, and the insulation not broken anywhere in a position in which a shortage could occur. A plug may now be examined and, if found to be dirty, that is to say, internally, sooty or very oily, it is reasonable to assume that the others are in the same condition. Therefore, take them out and clean them, for which purpose a small quantity of petrol may be employed to rinse them in, although, of course, one must be careful as to its after-disposal. En. passant, it should be mentioned that one should never throw petrol down a water drain, and if it is necessary to throw the spirit away do not so dispose of it en masse, but sprinkle it about in small quantities over a good area, so that it will quickly evaporate. If by chance someone should throw a light down, it is only the few spots in question which will fire, and conse- quently no damage is done. About the Plug Gap There is usually too great a tendency to have a wide gap between the electrodes of the plugs ; the best work- ing distance between the points of a plug is .4 mm., or (very roughly) the thickness of a. fairly stout visiting card. Either more or less is, generally speaking, con- ducive to bad running, and is also detrimental to the ignition system itself. Also note if the tips are clean, if not they may be cleaned by the use of a very fine file, if one has one, if not one can generally use the blade of a penknife and carefully push it through, which is usually a fairly satisfactory means of doing the work. If the width of the gap is found to be too great the prong of the electrode should be very gently tapped over with a good-sized key, or carefully bent, as may seem more easy to the person concerned in the adjustment. Many motoriste are inclined to think that a wide gap in the plug means a big fat spark, and therefore a higher rate of flame propagation, and consequently more power. It must be remembered, however, that for other purposes it :s necessary to provide a safety gap in 44