IMPROVED SPARKING PLUGS

New Zealand Herald, Volume LXVII, Issue 20538, 12 April 1930, Page 14 (Supplement)

IMPROVED SPARKING PLUGS

GEOLOGICAL DISCOVERIES.

Those who drove motor-cars a few years iigo will recall vividly among other troubles, tho inconvenience caused by cracked spark plugs. To-day wo have practically forgotten about spark plugs, as they havo ceased to bo a sourco of .trouble, and ono hardly ever hears of a cracked porcelain any nioro. Tho reason why spark plugs do not crack, and the way this improvement was brought about, was recently described by a member of the United States Geological Survey, who said that in June, 1926, in tho course of field work in California, a geologist saw an outcrop of rock that had been taken Ly one prospector for silver ore and by another for phosphate. It evidently was neither, aud so far as its appearance indicated was merely ono of tho host of rocks that' compose tho bulk of tho earth's trust. However, the geologist, recognising the mass to bo of an unusual character, stolo timo enough from tho otherwise economic work assigned to him to gather specimens and to ascertain the facta of its occurrence. Later, an examination of liis collection showed that the rock was largely composed of a mineral called andalusite. At that time andalusite was not known to havo any economic value. But, becauso of its scientific interest, a description of the occurrence was published in a scientific paper. ' Before that timo tho silicato minerals had been one of tho many subjects of investigation by the geophysical laboratory, which had, among other things, determined what to the layman might appear to bo a bit of perfectly useless information, tho amount of swelling and shrinking shown by andalusite and other minerals when they wero heated and cooled or, in scientific terms, their coctlicients of expansion. The geologic paper and tho results worked out by the physicists fell into tho hands of engineers. looking for substances with which to make spark-plug porcelains that would not crack, and andalusite was the answer.

The geologist's research had found the 'deposit, and tho physicist's research had shown its suitability for the purpose sought. Again in , tho courso of field •work, this time in another part of the country, the same geologist discovered another scientifically interesting occurrence, a mass of tho mineral dumortierite, which, in tho course of events he described, and of which tho physical properties had been made known as before, with the result that tho spark-plug makers ■were directed to ar deposit even more valuable for their purpose than tho andalusite. To-day as an indirect result of purely scientific, uneconomic investigations, motor-cars are driven with never a fear of a " missing " plug.

ROAD TO 10,000 FT.

Motorists on the Island of Maui, Hawaii, will soon be ablo to drive to tho " House of the Sun." A road to the top of Halcakala, the world's largest extinct crater, will lead to tho highest rim of ,the giant sleeping crator 10,000 ft. above sea level. Tho mountain has a circumference of 20 miles and is ono of the main touring attractions of tho Island of Maui.

In its offering of gorgeous panoramas of great extent, tho new highway will lie unexcelled by any scenic drive in tho ■world. From. Puu Pahu, at 6000 ft. elevation, five islands of the Hawaiian chain will be visible, rising from the blue plain of the outstretched sea: West Maui, Molokai, Kahoolawe, Lanai and, in clear weather, distant Oahu. The 'island of Hawaii is visible from the brink of Haleakala. At the present timo there is h road to within ten miles of tho crater rim, and the remainder of the trip is made o;i horseback or afoot.

MONUMENT TO RECORD HOLDERS

A monument in honour of the makers of all officially recognised world speed records is to bo erected at Daytona Beach, Florida, where most of the major auto"mobile straightaway trials of recent years have been staged. These achievements date back to 1898 when Chasseloup-Lau-bat, tho Frenchman, astounded the .world with a speed of 39 miles an hour. Since that time the speftd record has been broken 31 times by 25 drivers, a ]jst including such familiar names as Barney Oldfield, Ralph De Palma, Tommy ]\lilton and Henry Ford. The Daytona Ueacb speedway has been tho scene of every record-breaking achievement since Sir Henry Seagr&va, of England, in 1927 attained a speed of 200 miles an hour. Since then the record has been boosted to tho present mark of 231.362 miles an hour, which Sir Henry set last spring after his old time of 203.79 had twice been broken, once by his countryman, Captain Malcolm Campbell and once by an American, tho lato llay Keech.

REDUCING WEAR.

Increased engine speeds have in recent years directed attention to the urgent necessity of reducing wear as well as facilitating readjustment and replacement of wearing parts of power units. That thero has been considerable responso to this need was to be easily gathered from a study of many of the exhibits at Olympia in November last. Thero appears, however, to be a tondency among a. number of engine manufacturers to overlook tho means now available for reducing reconditioning costs. From tho maufacturing point of view it is, of course, necessary to study' the fluestion of production costs very carefully, and before introducing any departures from previous standard practice their value to the user in relation to any increase in purchase price they would in* jvolve must be fully considered. In theso days of keen price competition a cautious policy in this respect is likely to be followed by tho majority of makers so long as users regard low first cost as of p'rimnry importance. It is evident, however, lhat experienced operators aro realising irioro and more that it is more economical <o pay a higher prico for their machines jf they cart be kept longer in service between overhauls, and if necessary repairs »:an bo executed in a shorter time than before.

For the reduction of engino wear t'jnrc appears to lie greater possibilities in the use of better wearing materials than by ■the improvement of lubrication. The parts chiefly concerned .are those where sho engine power is first applied; namely, tho cylinder walls and the connecting rod and crankshaft bearings. Promising results have been obtained in this direcfion by the use of renewable cylinder liners of steel and centrifugidly cast iron, ,which, in addition, avoid reboring and (fitting oversize pistons when wear occurs, Lall and roller crankshaft bearings that require minimum lubrication and special uteols case-hardened without distortion by Iho nitriding process. Of these tho first lias already found considerable favour iimong British and Continental manufacturers ; tho second has been adopted with success on tho Continent cither by the use of a built-up crankshaft or employing special anti-friction bearings adaptable to crankshafts machined from the solid; thi third, so far, has been adopted experimentally by both British and foreign ongino makers, but it is difficult ifco suggest any reasons why its advantages should not bo fully realised. All ihesn means of reducing wear admittedly involve higher production cost, but, even bo, we aro of (ho opinion that their adoption should receive moro serious consideration as preferential alternatives to jolder practices which at present fiivc bo Jnuch cause for anxiety to maintenance (jngmeers.