Revolutionary Design Of New Sparking Plugs

Poverty Bay Herald, Volume LXIV, Issue 19248, 13 February 1937, Page 9

Revolutionary Design Of New Sparking Plugs

ICFYKRAL inquiries have been reI 1" reived, says ihe Sydney .Morning Herald, abotii the rather revolutionary design of sparking plug with platinum central electrode, which was introduced from England late in If'•"'Hi. 1 Tim design i , of \i'i-y great lei hnietil interest, representing, as n does, ilie only real alteration which has jboeji made in more than I'D years 1.0 JI his most import am unit of Ihe ignition system. j The ci in in I elect rode of a sparking , ping of normal design is made of Ivory hard sn-el, and, while this is ; satisfactory. it does lend to bum away lairly rapidly, especially when operating under the arduous conditions imposed by modern high compression engine-. In order that Hie gap lie maintained at the most, eilicient measurement, it is necessary to reset it about every 4000 miles to compensate for the metal burned off. While this does not involve any hard work, it is doubtful whether many motorist- I.other lo cheek the gap as often as they should, and it is possible that manv engines are used with .-parking plug gaps that arc 100 wide. The new sparking plug has a Hue platinum wire set in the end of the central electrode, and it is from the platinum point so formed that the spark bridges the gap between il and the outside elect rode. Durable Metal.

Platinum has a very high resistance 10 heat, and i; is claimed that this point will not burn away during the life ot the car, and that the gap never has to be reset. Furthermore, if can safely be operated at a very -high

temperature, at which a much lower voltage is required to bridge a given Sap. (Vinsoqhently, if the normal gap is retained, the stress on the ignition system is much reduced; alternatively the gup can be made much wider than is usual without requiring abnormal voltage, and Uiis increase iu width will give a marked improvement irt starting and slow running. Actually, with the new ping, it is customary to operate it with a gap of between -0 and L’b thousandths of an inch. This comparatively low voltage feature enables the plug to operate satisfactorily when it is dirty, while another peculiarity that has been discovered is that the platinum point refuses to retain a drop of water across the gap, so that, the new pi tig is not likely to lie put out of action by condensation tit the points. It has boon found also that, with the new plug, pre-ignition does not. occur. Mr. 1). M. Ca.stle, formerly of Auckland, is 1.0 leave Ipswich, Suffolk, for Iraq, to join the l’oyal Air Force there.