MOTORS AND MOTORING

Dominion, Volume 11, Issue 33, 2 November 1917, Page 9

MOTORS AND MOTORING

IB? Clxttoh.l

Tyre Economy, The mileage obtained from tyres varies most romarKably, even with tho same pattern of .tyre 011 tho samo model of car, and, whilo evory motorist is naturally desirous to get the most lie can out of liis tyres, luck or chance enters very largely into the question. At the same time, even though the best of tyres are iitteu, method or good management is a, great factor in determining tho lengtn of servico (expressed in miles) from a set of pnoumatics. A plan of interchange that helps in lengthening tho lifo of tyres is, after the car has run 1000 miles, to take olf the right rear cover and carry it as a spare, replacing it with, a now spare. At the end. of another 1000 miles the left , rear cover is removed, and iitted on the left-front whaei, and a new or little-used tyro, is placed on tho right rear wheel. ' Thus tho tyres are kept moving from wheel to wheel in a clockwork direction. . it .is assumed that tho right rear or oft'-sido tyre has leas wear tnan that on tlia near side, as it generally has tho better surfaced portion of the road to run upon; but that really is of little moment when tho changing of the tyres is effected every 1000 miles. As each new or littl-ueed cover comes into use, or is changed from wheol to wheel, especially from off-side to nearside, care should bo taken to reverse tho direction of travel; motorists of long experience assert that this practicc, carried out methodically will add many miles to tho'effective usefulness of a tyre. Whore cars aro fitted with interchangeable wheels—and there aro somo on which all lour wheels aro standardised--tlio process of changing about the tyres is much simplified.

Carbon Deposit. Muoh oil is wosted and carbonisation accelerated, by the great heat generated or attained" in the piston head, which, presumably, is the Hottest part of tho internal combustion engino. There is no obvious reason why oil should ever reach tho lower disc of the piston head; and if - this can be prevented without introducing counterbalancing faults tho oil will keep cooler, more work will bo done with it, and carbon will form much less slowly. Carbon deposit inside the piston is the hardest to get rid of, and with motor-cyclists it is often left untouched, being difficult to bo removed without the. gudgeon pin being released —a job from which the average rider is apt to shrinkj and not without reason. The inside of a piston: really acts as a little roasting oven.for the oil, while'tho carbon so formed is mildly abrasive in character, whioh naturally helps to wear down the bearings, besides .-wasting the oil. An effort 'is being made to keep the piston head cooler by adding a dummy head—practically a double-decker piston. As carbon formed- in the combustion chamber is deposited only on surfaces which are not in contact with other surfaces, it by a natural accumulation, fills Tip the empty nooks and spaces, and probably its presence there is duo to tho escape of hot gases. By filling up thesa empty spaces, it makes up for deficiencies m fit, and its presence quite conceivably prevents the escape of useful pressure at those-points whore there is no metallio contact to prevent it. In cleaning the' cylinder head it is the practice to removo every particle of carbon deposit, not only from the head, but also from the sides of tho piston, the piston grooves, otc. An expert declares that there is nothing to be gained in cfcaning out the'piston rings ana grooves;' .but ho adds that' if one of tho piston rings is "gummed up" it is, of course, nocessary'to remove it and replace it cleaned and polished into the carefully scoured groove. If tho rings are free, and performing their function satisfactorily,, it is far better to lcavo them alone. i

Here and There. Driving a car around a sharp oorner at twenty-five miles an hour does more damage to the tyres than twenty miles of straight road work. Exoessivo side pressure on tyres may pinch the tubes and it always strains tho sido walls of the casings. ' The majority of modern mbtor-cars develop their maximum cfficioncy with lowest expenso at speeds ranging from fifteen to twenf.y-fivo miles an hour, depending on the make of the car and condition. of the roads.

Among tho necessaries whon touring should be,a supply of tyre valves and caps. A slight leak in a valvo will cau/le a!> much daluy as a blovr-out. A good valve is often hard to obtain when on the road, and considerable annoyanco can be avoided by carrying these accessories. A valve tap and die should also be added. , ■ _ , An American verdict: 'The automobile lias brought good roads, officienoy in industry, bettor wages, and better factory conditions, and a higher goneral standard of botli labour and pleasure than the world knew in all tho centuries before its invention. It is the greatest, modern convenience; it is directly responsible for a big share of America's happiness, prosperity, broad-mindedness, and general alertness." . . Plain cold water, a judicious application of soap and plenty of care aro -without rivals, in preserving the hnish ol ! a motor, whether it be the top, the leather cushions,-tho varnished body or the' enameled fenders. A non-scratching polish may be used on the nickeled parts. Care in washing a car is woll worth whilo, for it pays a big return in appearance. ■ If you have detachable wheels,.remember that the metal parts may rust, livery time you change a wheel cover the metal contact surfaces with grease, otherwise tho detachable wheol will no longer be detachable. Don't start the motor -with wide-open throttle or far-advanced sparlc. Don t put oil in the crankcaso before first seeing that it'is' free from dirt. Whon two or inoro leaves of a spring break, it is not advisable to instal new lcave3 without resetting tho spring. If tho spring is used for some time its set is different from that of tho new leaves installed, and the effect results m another broken spring very soon. Liglitang-up time; 10-day, 6.32 p.m. Next Friday, 6.49 p.m.