MOTORS AND MOTORING

Dominion, Volume 24, Issue 201, 22 May 1931, Page 14

MOTORS AND MOTORING

(By

"SPARE WHEEL.”)

Avoid rubbing tires against the kerb when parking a car. This action weakens the walls of the tire.

'The proper time to add water to a battery is just before Ihe ear is to be run, not after puting it in the garage.

"What makes our car so hot, so hot?” ■ "Why, this, my darling daughter: "You give it scads of gasoline, “But nary drop of water.”

All patches put on inner tubes must be vulcanised, as cold-cured patches lift off when the tire warms up. It is useless for the average person to attempt to repair an outer cover—this can only be done by an experienced man. It is unwise to allow the petrol tank to become completely empty, as this results in foreign matter being drawn along the suction pipe into the vacuum tank or carburettor. It is desirable to drain off the petrol tank about once a month. There is usually a plug or cock provided for this purpose. If a car is fitted with a vacuum tank, this also should be drained once a month, by drawing off a little petrol from the cock or plug fitted to the bottom of the vacuum tank. If any dirt has accumulated, this will then come away. V * * PUBLICATION RECEIVED. Fred. Berry’s “Motor Annual.” A well-compiled book brimful of much valuable motoring information (both for new and old drivers), clearly explained articles, and . helpful .illustrations. A real self-help publication for the owner-driver.

FOUR-WHEEL BRAKES

Correct Adjustment

EFFICIENCY IMPORTANT

The importance of correct adjustment of four-wheel automobile brakes was recently demonstrated by tests conducted at the National Physical Laboratory, London. A working model of a car was used in the experiments. It was found that the model skidded perfectly straight for 4 feetwith all four brakes on and the wheels locked.. With the two rear wheels locked the ear skidded 9 feet forward, and deviated 1 foot to one side, while with the two front wheels locked the machine skidded 5 feet forward and kept a straight course. With both front and the right-hand rear wheel locked there was a skid of 4j feet and a slight deviation to one side. The investigation resulted in the following conclusions : —The tendency to overturn is specially marked at high speeds with the following brake combinations. Two rear brakes only in operation—a diagonal pair of brakes — and also when one front and two rear brakes are applied. In the case where the front brakes lock the wheels of a car, the driver has little or no control aver the direction of travel so long as those wheels are locked. On the other hand, when the rear wheels lock, the stability of the motion is better under control. These experiments indicate the importance of correct brake adjustment.

Nowadays, with high speeds and more road traffic, the efficiency of automobile brakes becomes more important than ever. The standardising of four-wheel brakes has given to motorists greater control over their vehicles, but at the same time has introduced a more intricate braking system when it calls for adjustment. The appearance of so many black smears of rubber on the surface of city streets is only too significant evidence of the number of automobiles that are running with unevenly adjusted brakes. Admittedly not all brake systems are easy to correctly adjust, and where there is any doubt in this respect it is advisable to let an experienced mechanic handle the job.

For those who desire to handle the adjustments themselves, one of the best ways is to jack up both axles so that all wheels are free of the ground at the same time; then cut a strut to press down.the brake pedal from the dash or from front of seat, whichever is the most convenient. Go to each wheel in turn and make the adjustment so that you can just manage to turn the wheel by using the whole of your strength. Compensated brakes present the greatest difficulty and may make it necessary to go the round of the wheels several times. This is because individual adjustments affect the other brakes. In carrying out such an adjustment it is well to remember that worn treads of tires do not give the same road grip, as do covers with the patterned tread in good condition ; also that tires should be evenly balanced as regards tread surface on the wheels of each axle.

CAMPBELL’S BLUE BIRD

Some Interesting Facts

At a dinner in London tendered to Sir .Malcolm Campbell by the British Racing Drivers’ Club, upon his return from America, after rasing the world’s automobile speed record from 231.36 m.p.li. to 245.73 m.p.h.—a speed of over 4 miles per minute —some interesting facts were disclosed.

It was stated by Campbell that only 4J minutes elapsed from the time he started his first run on the Daytona Beach (U.S.A.) until the completion of the second run in the opposite direction. He travelled in all approximately 18 miles—9 miles up and 9 miles down the beach, and made a turn, also having necessary refills of petrol tank and radiator made. Owing to the perfect condition of the tires at the end of the first run, no change was thought necessary, although special provision hud been made in the construction of the chassis to enable the Blue Bird to be quickly jacked up for a change of wheels.

It was also stated that although the maximum “revs.” of the Najiier engine were 3536 per minute, during one of Campbell’s trial spins—presumably when the gear lever slipped out—the revolution counter shot up to 5000 with out harming the wonderful engine.

Mention was made of the fact that had the Blue Bird on its record runs struck anything in its path it would have hit it with a blow of 30,000 tons. Sir Malcolm paid a tribute to the fine sporting spirit of the Americans he came in contact with during his visit. The American Ambassador, General C. G. Dawes, created much laughter when in supporting the toast of the evening remarked, “You’ve goth the man. you’ve got the car, but we’ve got the beach.” He also stated that he considered at men like Campbell. Segrave, and Lindberg helped to cement international relations more than a 1000 ambassadors and 50,000 politicians.

LEAKY CARBURETTOR

Source of Danger

A leaky carburettor should be attended to without delay, because, in this condition, it is a potential source of explosion and lire danger. When petrol can be smelled strongly when entering a closed garage it is time to have the carburettor float mechanism set in order before a backlire or a stray spark starts a lire that may destroy not only the ear, but the garage and adjacent buildings. Keep the tank supply shut off while the car is not in service until the required repairs can be made.

DON’T GRIP THE WHEEL

More effort is required to control awl steer a car when travelling at low speeds in city trallic than when a moderate or fast pace is maintained on the open road, which sometimes accounts for undue fatigue of which novices sometimes complain, while getting accustom cd to driving. But a more common cause for fatigue is occasioned by the habit of gripping the steering wheel tightly at al) times, so that the muscles of the hands and arms are continually under stress. This, of course, prevents the wheel from being moved freely and hinders the sensitive control necessary for accurate steering, besides interfer ing with the natural tendency of the front wheel to return to normal straight position on their own account after tak ing a curve. The facility for the front wheels to castor freely and with accuracy is essential both for safety and comfort of the driver, and therefore this action should not be hindered by undue interference by the driver, as happens when the wheel is gripped too tightly.