BE DISCREET !

NZ Truth, Issue 1187, 30 August 1928, Page 15

BE DISCREET !

When Buying Plugs When purchasing plugs it is not sufficient merely to go into a garage and ask for a plug without specifying the- type of, engine m -which it is to be used. ~ THERE are several kinds of plugs, but ■*■ for general purposes they can be divided into two types. One is a plug- m. which .-the, electroder. are of, moderate size, -and- the other m which the electrodes are of heavy section. The first type is useful' m engines which are liable to oil UP easily, the light section of the electrodes allowing them to get hot, whereby the oil :s readily burnt off. • This type of plug would obviously be unsuitable for fast' revolving engines m which the working temperature is high. An engine of that kind requires . a plug with plenty of metal m the electrodes so that they do not become incandescent, and fire the charge before the spark passes. If at any time it is necessary m an emergency to jjse a plug whose electrodes project further into the cylinder than the plug which is being replaced it is necessary to make sure that the body of the plug does not project sufficiently inside the cylinder to allow the piston to strike it. This can readily be ascertained by screwing the plug m and . turning the engine over very slowly by hand.