THE MOTORIST

Northern Advocate, 5 November 1932, Page 12

THE MOTORIST

TO CURE “SHIMMY.” 0 RIGIN ATINIt CAl'Shs. One of tho most curious and dangerous results of excessive axle tilt is exhibited when the front wheels yank violently and rapidly from side to side as the car is in progress- (says “Motor Transport.”). This condition continues as long as the speed of the truck and the road conditions remain unchanged. It is commonly called shimmy. Such a condition is initiated by an unbalanced wheel or by some irregular road surface which swings tho wheels slightly to one side. They then tend to roll in this new direction. Tho car, however, tends to continue straight forward. The wheels, due to excessive caster effect, are almost instantly straightened, with such force that they pass slightly beyond the straight ahead position.. During that brief moment while the wheels were (■jointed to one side the car has received through the springs and axle the slightly sideways motion. The car, forced to alter its direction, does so just as the wheels are whipped into the opposite direction. A definite lag in the change of direction which can only exist at certain speeds is required in order to have the side lunge of the ear -occur at the same instant that the wheels are whipped into the opposite direction. With the correct amount of caster effect the wheels will not bo whipped back with sufficient violence to cause shimmy.

The exact speed at which the condition exists is controlled by the flexibility of the springs, the air pressure in the tyres, the play or spring In the steering mechanist’, the weight of the wheels, and the weight of the car, but the basic, caus.e is nearly always excessive axle tilt.

Another cause of shimmy is an unbalanced wheel. This is move likely to show its effect when balloon tyres are used, ami usually occurs only at high speed. 'l’his condition can lie corrected by Jacking up the wheels ami attaching a weight to make (lie wheel balance perfectly.

Tliis is preferable to putting more air pressure in the lyres, as it corrects ihe fault without sacrificing riding qualities. A badly warped wheel will .sometimes cause a condition very similar lo shimmv.

Impropei adjustment of the drag link will sometimes cause shimmv.

On many engines (Hied with a fan (lie blades are painted the same colour as the cylinder block' and radiator honeycomb. Thus, when the engine is running the fan is practically invisible, and when making adjustments there is the risk that one's lingers may come into contact with the revolving blades—with painful results. It is a good plan, therefore, to paint the blades a bright colour, such as red, which will enable them to be seen Hearlv at all times.

NIGGARDLY LUBRICATION. So much publicity Ims been given to tho need for running-in a. new ear carefully that the veriest novice in motoring could hardly plead ignorance of that precaution, but it sometimes happens that the real benefits of a steady runmng-in are lost because tho motorist, who is driving a new car carries out his duties in a perfunctory and incomplete manner and fails to realise that the changing of the engine oil is as important as the observance of strictly moderate speeds. The following warning, published in the “house” .journal of one of the best-known British manufacturers, may well be taken to heart by all those who are “penny wise and pound foolish” with regard to the lubrication of a new engine: “One of tho cheapest and most effective forms of insurance against mechanical breakdown and against ‘falling out of tune’ is to drain oil! all the engine oil after the first 500 miles, to repeat that procedure at the conclusion or the thousand, and thereafter to do the same thing after every two or three thousand miles. This is not a costly process; it is indeed a paying proposition, for it means that at the end of a year 's running your engine will h? ‘hotter than new.’

“Too many motorists think that they have done enough when they have added fresh oil in order to bring the lubricant up to the right level. They forget that quality is just as important as quantity. Engines are like human being and prefer a fresh glass for a fresh drink, having no tolerance of the dregs of that which is ancient history. . . But anyone so foolish as to ]iut in a little extra for luck may do a great, deal of harm to his engine for the connecting rods may throw up an excess of oil upon the cylinder wails whereby carbon deposit will be encouraged, to say nothing of the fouling of spark plugs and the gumming up of piston rings.’-’ EVE’S INFORMATION. The following, states an exchange, are some questions and answers, as given by women learning to drive motor ears, at a motor school in Victoria, Australia. Q.: In parking the car, which side should be next the kerb? A.: The side nearest the footpath. Q.: Which of two cars has Ihe right-of-way at a street corner? A.: The one that gets there first. Q.: What is the proper precaution to take when backing your car? A.: Reverse your engine. Q.; What is the magneto? A.: The name of a thing that lias something to do with the inside ol a

Q.: What is the charging indicator? A.: Vonr account for oil and petrol. Q.: What is the first rule of the. road ? A.: Don’t run into anything. Q.: "Where should you display tlio registration number? A.: On your car. Q.: What is meant by "short circuit”? A.: Going around the nearest way.

STARTING- BY HAND

EASIEST AND SAFEST WAV. Many motorists have very little idea of starting an engine with the handle, and sometimes fail altogether when some cold morning the starter refuses to work for the first time.

The easiest way of starting an engine, and also ihe safest, is first to crank it with the ignition switched off and the strangler fully closed. Turning flic engine over a few times in this way will ensure plenty of fuel reaching the cylinders without risk of a backfire.

The ignition lever should then bo well ictarded ami the ignition switched on. Engage the starling handle so that it points straight down; put four

fingers round it, but not the thumb, iuul give a sharp pull up. This "will allow the hand to disengage and pull nut. of the way in ease of a backfire, nr should the handle refuse to disengage when the engine starts. The latter is not an uncommon occurrence with some of the poorly-made detachable handles usual on modern cars, and, like a backfire, it may easily cause a broken wrist.

Detachable handles should be very carefully engaged with the dogs on the front of the crankshaft. Otherwise the handle may come off and cause a black eye. Blisters on the hands quickly result from stiffness in the turning of the sleeve, over the handle grip. Tf no sleeve is fitted, as is the ease with many cheap cars, always grip the handle with a handkerchief, ft should bo remembered that a large throttle opening does not always facilitate starting.