SPARK PLUGS.

Press, Volume LXIII, Issue 18911, 28 January 1927, Page 6

SPARK PLUGS.

ILLUSTRATED LECTURE. A very largo gathering of motor enthusiasts assembled at the Canterbury Automobile Association's rooms on Tuesday night to witness a special screening of an educational film, "The Story of a Spark Plug." An interesting address was delivered by Mr O. A. Speers, who is at present in New Zealand representing the Champion Spark Plug Company of Windsor, Canada. In the course of his lecture, Mr Speers dealt with many problems in connexion with the ignition and the conservation of petrol. The picture, which the lecturer had projected in Africa and Australia, showed by slow motion the workings of a motor-car ongine, and also displayed the spark plugs in the making, from the mining of the sillemanito to the finished article, the process being very closely followed by the audience. It was explained that by the continued use of a spark plug for 8000 to 10,000 miles, the bottom portion of, the insulator became coated with particles of carbon and minute particles of the wearing of the walls of the cylinder, which, mixed with the road dust, formed the coating. This caused a leakage, so that only a portion of the electric current operated, resulting in the spark losing its intensity because of the great stress to which the plug was subjected in the engine operation. The engine was sluggish, power was lost, and petrol and oil were wasted. -Mr Speers stated that the installation of new pings once a year was not by any means an expense, but an actual economy, for the reason that they paid for themselves in the amount of oil and petrol saved. The installation of these plugs made a saving in another direction as well, and that was by frequently sating motor overhauling and similar expenses. Mr Speers also showed several race films of different European Grand Prix races, including one of a race over cobblestones.

Several samples of the raw material of which the plugs are made were on exhibition.