MOTOR & CYCLE

Taranaki Daily News, 6 August 1932, Page 3 (Supplement)

MOTOR & CYCLE

ON HANDLING A CAR

THREE TYPES OF DRIVERS. NEED TO ACQUIRE KNOWLEDGE. (London Motoring Correspondent.) Driving a car is so easy nowadays, thanks to lightly operating controls and the high standard of mechanical excellence of the modern vehicle, that it is often forgotten by many motorists that there are degrees of driving efficiency. These may be classified as driving, good driving and better' driving. To my mind driving merely consists of piloting a car through the streets or along the reads without coming into contact with other cars, road users or obstacles. It represents the lowest form of driving efficiency-—knowledge of the operation of the controls without imagination. It is thia type of driver who keeps to the crown of the road most of the time, chooses the narrowest winding lanes for crawling along with the result that no other car can pass, makes a habit of trying to turn in the most crowded city thoroughfares, reverses in a series of jerks, parks his car two or three feet from the kerb and generally makes himself a nuisance to everybody without actually breaking any motoring law dr damaging his own or anybody else’s. car. The good driver commits' none of the aforesaid offences and does his utmost to show consideration to all. other road users by giving signals which state his intention clearly; in fact,’he gives evidence all the time of knowledge of the controls plus intelligence. He eeems to be able to gauge' exactly when he can overtake without inconveniencing anybody, he knows to a moment when ho ought to take his, foot off the accelerator -pedal preparatory to slowing down, And. he knows also what it is safe to do and what it is not safe to do. ■ ' 'KNOW YOUR ENGINE. Now we come to a definition of the better driver. . I would describe . him as a driver who in addition to using his controls intelligently, and doing all the things implied in the term 4, road sense,” has also as complete a knowledge of •: the mechanism and capabilities of -his car 1 as it is possible for any motdnst who is not an engineer to possess; The “better” driver and his car. react upon each other all the time. He knows from .the note of . his engine what sort of mood it ie in, and he handles his car , accordingly. He knows in short how to get the best out of. his car, and in getting the best out of it he also, of- course, gets the best out of motoring. By way of illustration I may give one instance of , the additional knowledge which goes to the making of the better driver. Most drivers when they are nearing the top of a.hill automatically press down the accelerator pedal when the car begins to slacken speed. But the knowledgeable driver does, just the reverse. Instead, of opening the throttle more he, closes it slightly with • almost imperceptible touches and the result is that the engine is helped to do its work. One of the annoying things to a motorist is to see a. fellow-motorist with exactly the same model pass him on * hill. As often as not the explanation is that the passer is a better driver than the passed. It may be that he knows how to control the throttle and the probability is. also that he knows exactly when to change down to a lower gear. These and other driving refinements can only be acquired by ap intelligent interest in the mechanism of the car and by constant study of its performance under all conditions. 1 CARBURETTER LORE.

From a recent 'Automobile Association return I notice that during one month this year no fewer than 2306 A.A. members called upon the patrols for assistance to overcome carburation trouble. I think I am safe in saying that the large majority of these car owners do not belong to the better driver class, and I , suspect that their carburation trouble was not much more than a choked jet. The better driver cleans his filters periodically, uses only a reputable brand of fuel and seldom has trouble with his carburetter. But even if trouble comes he knows how to deal with it. It is curious how few car owners take pains to find out how to dismantle a carburetter and clean it. With the modern carburetter there is nothing simpler in the world than to take it down, remove any foreign matter and re-assemble it agai- 1 . But that is the worst of the modern car. It discourages all mechanical initiative with the result that even the carburetter is looked upon by many as something with which only a qualified mechanic can take liberties. To good drivers who aspire to be better drivers I. suggest, as I have probably done on previous occasions, that they should ask the mechanic at their garage to show them 'how to get the better of a choked jet. The small gratuity consequent upon such information will prove well-spent money. It may even save the considerable expense of having to summon aid from a distance. TWO REFINEMENTS. I mentioned as one of the attributes of the indifferent driver the inability to park his car close to the kerb. In this connection it is strange that so few otherwise good drivers take the trouble to acquire the knack of parking a car neatly close to the kerb. It only wants a little practice. Tha.t such inability is widespread is evident from the fact that in one of the eliminating tests in the Scottish rally a car must be parked with its near-side wheels five inches from the kerb. The thing is by no means as easy as it sounds, but the knack can be acquired with a little practice. Chauffeurs as. a rule. are. remarkably good at it, and it is a real pleasure to see them slipping into what many amateur drivers would consider an inadequate space. They can do it as a result of practice, and the owner-driver who takes a pride in his driving should emulate the chauffeur in this respect. Another refinement worth practising is starting on a steep hill. Much indifferent skill in that respect is to be seen on any steepish hill leading to a busy road. The policeman’s hand goes up and the leading car stops promptly, but it is a different matter when the leading car tries to start again. In many cases there seems to be no co-ordination in releasing the handbrake and pressing down the accelerator pedal, with the result that the car as often not ■bounds forward or begins to slip back to the alarm of all the following cars. Here again the better driver scores. He has learnt so to co-ordinate his movements that even on the steepest hill the car glides away smoothly and gives every indication of having an expert at the wheel.

BRITISH MODELS.

MANY COMMERCIAL TYPES. A summary of the cars and trucks now being manufactured in Britain provides some interesting facts. All told there are 35 manufacturers of cars, covering 111 models, and 46 makers of trucks, extending over a range of 270 models. The most striking feature of these figures is the huge number of types of commercial vehicles made to cover the variety of services to which British motor trucks are now being put throughout the Empire. The carrying capacity of these trucks ranges to as high as 30 tons. Of the 270 models, all but seven are shod with pneumatic tyres. The avenge horse-power of all the types of cars is 19.5, which is surprisingly high considering the large percentage, of light cars now being made ano sold annually in Great. Britain. It is interesting to note that the average hbrse-pbwer of Continental types of cars sold in England is 22.9, and that of the American types sold there, 31.13 h.p. The relative truck horse-power figures are: British 27.42, Continental 33.1, and American 25.941 . u As regards the power units of the British cars, 19 models are fitted with four cylinders,. 29 with six cylinders, four with eight cylinders, and one with

FLOORBOARDS. METHODS OF FITTING. A weak point on the bodywork of a great number of cars, which body-mak-ers have been slow to correct, is the method of constructing and fitting of floorboards. Some cars, of course, have well-designed boards fitted with aluminium or other metal frames, and provided with sturdy and positive catches for holding them in place, but a great many other floorboard’s are of ordinary soft wood, generally too light for the purpose, secured in place with screws. When it is necessary to remove the floorboards to gain access to units, such as the battery or the gearbox filler, it is difficult to imagine a less convenient arrangement. The removal of the screws, especially on the front corners of the floor, where one must work in the restricted space under the dash, .is difficult, and the operation is so long that battery "topping” ie generally undertaken far less frequently than it should be. Moreover, when the screws are removed, it is practically impossible to prevent grit from working into the screw holes. This impedes the replacement of • the screws, and ultimately breaks away the wood, so that the screw will no longer grip. The difficulty can be overcome permanently by fitting small brass screw buttons, of the type used as catches on safes and small doors, to the sides of the body, so that they can be used to hold the floorboards in position. When these buttons are fitted it will probably be found that the boards lie loosely in position—a certain source of rattle. To correct this, strips of rubber cut from an old inner tube, or, better still, strips of sponge rubber cut from a cheap rubber sponge, should be fastened with small screws to the underside of the edges of the board. This rubber will then compress when the board is in place, and will make a thoroughly rattle-proof job.

WHEEL WOBBLE. CAUSES AND A REMEDY. « / . ■ The most common cause of wheel wobble is a loss of the tilt or castor setting of the front axle, which is always tilted slightly backward so that the wheels will tend to swing back to a straight-ahead position after they have been turned to one side or the other by means of the steering mechanism. This tilting of the front axle is also of benefit in that it lessens the shocks and jarring caused by the front wheels striking irregularities in the road. The most frequent reason for loss of front axle tilt is the settling of the front, springs, and its. effects are much more pronounced with modern cars because of the use of balloon tyres and very sensitive and light steering apparatus. But investigation has also revealed that the settling of the rear springs will aggravate the condition. The . common remedy is to insert thin wedges between the axle and the front springe, and so to restore the original degree of tilt, but motorists are not advised to undertake this experiment haphazardly. While it is possible by a process of trial and error and the experimental use of wedges of different thicknesses to obtain the desired result, it is far better to have the work done at a well-equipped service station.

TESTING CARS. INGENIOUS MECHANISM. An ingenious mechanism for testing the various capabilities of cars was introduced in England recently. The tester consists of a set of drums all mounted on ball-bearings supporting the front and rear wheels of the car or chassis, one drum being directly coupled to a Froude dynamometer of the type which has been adopted in most parts of the world for testing automobile engines. The dynamometer is supplied with water from the mains and resists rotation of the drum to an extent which can be regulated by means of a single hand-wheel. The arm of the dynamometer pulls upon a weighing machine arranged to show direct and instantaneous readings of the tractive effort and brake horse-power at the surface of the power drum. A pair of ramps is mounted at the rear end of the plant so as to permit cars of varying wheel track t run up them under their own power. On reaching the upper end of the ramps, the front wheels sink into the space between two rear drums, but do not remain there, passing on until they come to rest on front drums mounted on a, trolley running ’n tracks which are laid down on the floor of the test shop. A safety device prevents the trolley from moving forward until the front wheels have come safely to rest upon it. By means of a hand winch, the car and the. trolley are moved into testing position, in which the rear wheels rest over the rear drums. A flowmeter is connec’ d to the carburettor, and auxiliary cooling arrangements are quickly adapted to the radiator to allow for the absence of the cooling air stream experienced on the road.

RUNNING COSTS.

BEAL RELIABILITY. That there is scope for improvement, in spite of the extreme reliability of modern cars, is shown by the records of some modern commercial vehicles. Discussing running costs with the owner of a fleet of high-grade trucks recently, an Australian writer was told that six of these vehicles, which had been on the road between 11 and 12 months, had already covered up to 43,000 miles each, the "laziest” having 37,000 miles to its credit. Only one of them had had the cylinder head lifted, at 42,000 miles, and so good was the condition of the valves that it was decided not to disturb the others. Repair costs had been nil, and tyre mileage had averaged between 30,000 and 40,000. Such running economy is the result of several factors. In the first place the vehicles were of the highest grade. All the drivers were well trained, and rigid supervision prevented both high speeds and overloading, the two chief causes of mechanical trouble with trucks. Finally, each vehicle received regular and skilled attention, both as regards lubrication and adjustments, tyre pressures, for instance, being checked twice a. week. Many users of motor-trucks, more especially those in a small way of business, who cannot afford to waste profits, fail to obtain satisfaction simply because of neglect. The cheaper type of vehicle, especially, requires reasonable care to enable it to be used most profitably. The arrangement of adequate provision for maintenance is not a difficult matter, but the control of drivers is not always easy. A plan which has worked well is to set a reasonable standard of running costs, giving the drivers a percentage on the amount they can save on it. It is surprising the number of major economies a man who knows his job can effect when he has a direct interest in so doing.

CHANGING DOWN. THE RIGHT TOUCH. In changing down the most common fault, even on the modern car with its greatly simplified gear change, is changing too late. This may in some ways sound contrary to the idea of fuel economy, but the fact remains that a delayed change puts increased stress on the engine, requires greater throttle opening in consequence, and may often on a long steep hill call for a iurtner change down. Additionally, engines are designed to run most efficiently at the higher speed, and therefore it is cleat that the rate should be kept up whenever a severe and prolonged load has to be tackled. It is evident that where a driver has delayed his change down, so that eventually he has to make a further change, the engine will do many more revolutions over a given distance than would be the case in which, with a good driver, the change had been made early, one change sufficing. Moreover, ‘by over-late changing down average speed is lowered.

SPARK TIMING. HOW IT, AFFECTS COMPRESSION, How spark timing affects compression is little understood by the average motorist, yet it is easily explained. Since petrol vapour requires a measureablc period of time to burn, it is customary to time the spark in the cylinders to ignite the gas before the pistons reach the top of their compression strokes. With the spark properly advanced enough gas should start burning to compress further its unburned portion, bo that when the pistons start down on their power strokes they may do so with greater force. If the flpark is too early and too much gas starts burning the tendency Is for the pistons to be prevented from reaching the top of their compression strokes. This causes pronounced knocking, and during cranking results in back-firing. The faster the engine runs the more, within limits, the spark can be advanced with safety and efficiency. In this way the igniting of the gas charge itself affects compression and power. This knowledge is elementary, but if owners studied its effects they would obtain better performance from their cars.

THE FILLER CAP. ATTENTION NECESSARY. The rear petrol tank fitted with either pump or autovac feed to the carburettor 'demands a form of attention that is somewhat new in upkeep processes to a great many drivers, even those with many years’ experience. That is 4 o say, it is highly ■ important that the small air vent-hole in the filler cap should be kept clear by occasional probing to remove the mud and dust that tend to choke it. A blocked or partially choked vent hole may be the cause of erratic running of the engine, particularly when there is need to run the latter at high speed and full throttle, as in climbing steep hills. Air. cannot then enter the tank fast enough to take the place of the petrol that should issue to the carburettor, and.what is known as petrol starvation” occurs. Popping in the carburettor is sometimes a symptom. With autovac feed the result of a choked vent-hole may be far more serious, for if air ■ cannot enter the tank while the engine is running an intense vacuum is set' up inside it, representing, at its worst, a pressure of roughly 141 b. per square inch from every direction upon the' whole of the exterior surface, or nearly half a ton in a in the case of quite a small tank. The ultimate effect is that the tank is unable to withstand the stress and collapses, concertina fashion.

DANGEROUS PRACTICE. RUNNING ON WORN TYRES. There have been several instances in England recently where motorists nave come into conflict with the traffic police owing to the tyres in use being deemed unsafe under the regulations of the Road Traffict Act, which makes it a punishable offence to drive motor vehicles with tyres in a worn-out condition. The contentious point appears to be: When does a worn tyre become defective and a source of danger? A motor cover that has the tread pattern worn off and the traction area of the tyre quite smooth may be quite safe under certain road conditions, but on wet roads such tyres may be conducive to skids, particularly if brakes are suddenly applied. Covers with smooth treads on the back wheels are at all times wasteful, inasmuch as there is considerable wheel-spin, owing to lack of road, grip, with consequent waste of power and petrol. Covers that are so worn that several

plies of cord casings are cut through are approaching the danger mark, because they are likely to blow out when put under any undue stress. Covers in such a condition are a definite risk, particularly on hilly roads or when cornering at speed. Under no circumstances should tyres that are obviously nearly worn through be used on the front wheels of a motor vehicle that may be driven at even a fast touring pace. If they must be used, then it is better to reduce the risk by fitting such covers on the back wheels, and high speed should be avoided. Tyres are now so low priced that it is, really false economy for any owner or a motor-vehicle to try to get the last few miles out of tyres that are not fit and safe for further use. A wrecked car, with possible harm to occupants, is a heavy penalty to risk just for the sake of obtaining extra miles, which, after all, only represent a few pence, based on the modest outlay that nowadays will purchase even the highest grade tyres.