UNDUE SPEED HAS TO BE PAID FOR

Dominion, Volume 32, Issue 93, 13 January 1939, Page 13

UNDUE SPEED HAS TO BE PAID FOR

A Few Facts With A Bearing On Economy And Safety

The effect of speed on petrol consumption is quickly a f, re b« "ls..s «n.l nU. ot "ear ot tread are not so obnons as is the consumption of petrol.

Actually the modern pneumatic tyre is a spleiidid product, and if properly looked after gives a long and troublefree life. The length of that life is, however, a matter which is within the control of the driver, as he is lesponsible not only for correct inflation of tyres, but also for the speed at which his vehicle travels. No better Illustration of the effect of speed on tread wear is provided than the short life of tyres on racing machines in long-distance contests, during which high speed is reached. Tyres that would normally run anything from 15,000 to 20,000 miles are worn down to the cord casing in anything from 100 to 150 miles of travel. In a lesser degree there is even a. wide difference between tyre wear on a touring car driven under normal conditions and those of a fastly-driven sports car. Tests in this connexion demonstrated that the same amount of tread wear took place while a touring car travelled 5000 miles on the road at normal average speeds, and a sports car covered only 335 miles at 90 m.p.h. on a track. . / Fast travel on the road causes an abnormal amount of slip between the tyre and the road surface. This oc-

Punctured Carburetter Float. In most carburetters and vacuum tanks a float of hollow brass is used to control the petrol level, and if flooding occurs it may be due to the float having punctured. This can be veil* fled by shaking the float. To find the leak and expel the petrol, immerse the float in hot water, enlarging the hole slightly when found if necessary, to get rid of the petrol inside. Extreme care, however, must be taken when carrying out this operation not to allow petrol or petrol fumes to come into contact with a naked light. Soldering should be done very carefully so that the smallest quantity of solder needed to repair the float is used. Otherwise the increase of weight may raise the petrol level sufficiently to cause heavy consumption or further flooding. Cork floats may become soaked with fuel, losing buoyancy. Dry the float out thoroughly and give it a coat of shellac varnish or clear lacquer.

Removing Lamp Bulbs. When headlamp bulbs stick in their sockets, there is a risk of crushing them when attempting removal. A good type of holder which will grip without exerting dangerous pressure is a piece of H-lnch radiator hose, about an inch long. Slit it lengthways, and cut a few longitudinal grooves in its Inside surface. It Is slipped over the blub, and then gripped with the fingers.

curs to a degree at all times. Under normal running conditions it is found to be about 1* per cent., but on a rouga surfaced road at 60 m.p.h. it has been proved to be about 4-} per cent, to .> per cent., i.e., three times as much. As the rate of tread wear varies roughly as the square of the slip, it means that if the slip is trebled, as mentioned, the rate of tread wear is increased ninefold. The foregoing shows that undue speed has to be paid for. Motorists who travel above normal touring speeds are advised to change tyres round every 2000 miles to equalize wear. It is particularly important that the front wheel tyres should be changed round, as the camber and toein have a tendency to wear the tyre chiefly on the outer edge, of the tread. Some drivers never think of changing the tyres round. On the other hand, we know of motorists who make a practice of changing the tyres round every 1000 miles when the sump is drained and refilled. The wheels are changed from left to right, and front to rear. This changing round of the tyres means also an occasion to check up on the wheel nuts, greasing, etc.

Cleaning Spark Plugs. Spark plugs are constructed so as to resist great heat without damage, so long as the heat is applied uniformly and not too abruptly, and this provides a very simple method of clean-, ing them, whether they are of the detachable or one-piece type. Fix a length of wire to the plug to serve as a handle, and heat it in the fire or over-a gas flame until it is hot enough to burn off the deposit of oil or carbon. Hold It at this temperature for a few minutes, and allow it to cool off. All oil will be evaporated from the inside, and the carbon converted to a dry powder easily scraped away. Remove the copper gasket first, as the gradual cooling would harden it, spoiling its elasticity. Excluding Dust. Much of the dust which collects in car interiors rises through the rear floor. If you lift the rear carpet and seat, and stick wide adhesive tape over cracks and holes, the car interior will remain much cleaner.

Cleaning Fuel Filter. Leakage of air is a common trouble after the bowl of a fuel filter has been removed for cleaning and replaced. Often a cure is effected if the gasket Is removed and turned unside down, so as to substitute different surfaces and overcome Irregularities formed by constant pressure.