MOTORING AND MOTORISTS

Evening Star, Issue 22620, 12 April 1937, Page 13

MOTORING AND MOTORISTS

by "Radiator”

LIGHTING-!!? TIMES

To-day 6.39 Tuesday 6.37 Wednesday 6.36 Thursday 6.34 Friday 6.32 Saturday 6.30 Sunday 6.2'J

CITY DRIVING AT NIGHT

The greatest danger of night driving in populous areas comes from pedestrians in dark clothing crossing the road. This is mainly because the street lighting effectually “kills” the illumination from the car head lamps and throws conflicting shadows across the roadway, so that far too frequently the motorist is unaware of the _ presence of foot passengers until ho is dangerously close to them. It is because of thie danger that very great concentration is needed. The motorist cannot afford to let his attention wander for one instant from the roadway, and unless he is quite sure that he can see the road very clearly he should slow right down. There have been many most uhfor-i tunate accidents in which motorists have knocked' down pedestrians on badly-lighted streets, the unhappy consequences of driving just a little too fast when the illumination of the roadway was insufficient to delineate with absolute clearness everything in front of the car.

WHEN NOT DRIVING

OWNER’S LIABILITY The question sometimes arises as to the liability of _ the owner of a car which is not being driven by himself. ■lt has been held on several occasions that the question of control is all important. • The general principle is that, in the absence of special circumstances, the lender of a motor car is not liable for injuries paused to third persons through the negligent use of the car by the borrower. Where a servant is driving the car for the purposes of the owner, and an accident occurs as a result of the servant’s negligence, the injured party can claim against the owner as well as the servant. If judgment be obtained against both, and one, say the owner, pays the amount, then he is not entitled to contribution as to half the amount from the servant and vice versa. Mere ownership of a car per so does not involve the owner in any liability without showing that the person driving the car is his servant or under' his (the owner’s) control. Where, for example, the owner lends his car to his son and an_ accident occurs while the son is driving for his own purposes, the owner is not liable, as he has no control of the car. Difficulties arise where there are con-

siderations as to whether there has been any control retained by the owner so as to render him liable. The following examples illustrate the point : (1) A prospective purchaser, his son, and the owner of a car went for a trial run. The son drove and an accident occurred. It was held that the owner, by his action in allowing the son to drive, had not abandoned his right of control and was liable.

(2)_ The owner, who had a chauffeur, permitted his son to drive provided that the chauffeur accompanied him. The owner was not in the car when an accident occurred. It was held that an inference could be drawn from the

’act of the owner always insisting on tis chauffeur'accompanying his son that

he had not given up control of his car, which he retained through his servant the chauffeur. It can thus be seen that each case resolves itself into the question as to whether the authority retained over the driver of the car is such as to show that the owner had the actual control of the car.

SWITCH OFF YOUR ENGINE

It often happens that a motorist leaves his car with its engine running whilst he himself dashes into a shop for a packet of cigarettes or some other trifle.

In the driver’s mind there is only the idea that he will be away from his car for less than a minute, and the fact _ that he is creating a hazard, causing waste, and inviting theft does not make itself evident to him. The running motor at the kerb is a strong temptation to irresponsible persons who, enjoy nothing better than meddling with those things with which they are unfamiliar.

Once started ahead in low gear or backward in reverse the damage that the vehicle might do is inestimable. There is nothing more certain that the first move of the tamperer would be to desert the car and run for cover. Unattended, the machine may knock over and fatally injure some unoffending passer by, it- may crash into another vehicle and cause serious traffic congestion, or it may damage anything that impedes its progress. Of course, if the law were obeyed, as it should be. the leaving of engines running while cars are unattended would be unknown.

0!L IN TAPPET COVER

la many cars the valve tappets cover consists of a pressing of steel made concave in the centre m order to stiffen the plate. Niue motorists out of ten, however, always draw the retaining nuts down too tight, so that the plate is buckled and oh is free to leak from the bottom, where the plate Should make a good joint with the cylinder block. Careful tightening of the nuts so as not to buckle the plate should overcome the trouble, but if it still persists, and the packing consists of one large rectangular piece of cork, it is possible that oil collects between the cork and the plate, finding its way there via the stud holes in the cork. In order to allow the oil to drain back to the crankcase two or three holes may be cut in the cork near the bottom, or, better still, cut away the entire unused inside portion of the cork, leaving only a continuous narrow strip round the edge of the plato to make the joint. The packing should be secured to the plate with shellac, while the tendency to allow oil to leak will be minimised if the joint between cork and cylinder block is made with hard grease.

THE TOOL KIT

NEED FOR IMPROVEMENT About tiie worst feature of some modern cars is the tool hit (remarks an expert), which is generally poor m quality, comprises only the barest necessities, and is stowed away In some place where it is thoroughly inaccessible and involves disturbing passengers or groping about in the fastnesses of the rear trunk in order to get at it. Manufacturers apparently work on the theory that modern cars are so reliable that the owner rarely has occasion to use the tools, which is true enough as far as serious adjustments are concerned; but if the bools were housed in a place where they can easily be reached the owner would have some encouragement to rectify immediately such small loosenesses in the controls and bodywork which soon develop in every car instead of waiting until they become so loose that they cause bad rattles.

Apart from this, a long country tour in the best car is rarely unaccompanied by minor troubles to the wiring and parts of the body, and it is a great convenience if the small tools are easily accessible. Surely in even the cheapest cars it is not asking too much that a special pocket be arranged in one of the doors or the back of, the front seat to accommodate a screwdriver, . a. pair of pliers, a small adjustable spanner, and a plug spanner. This would be appreciated by every motorist, and the tools would be used on minor adjustments much more frequently, to the car’s benefit, than they are at present.

A very neat arrangement which is just about ideal was seen recently on a small English car of rather high quality. A shallow drawer was arranged beneath the facia board, and when pulled out this disclosed the small tools, each lying in a speciallyshaped, felt-lined recess in the drawer, from which they could instantly be taken, while the arrangement was such that it was impossible for them to rattle about.

This brings us to another point. In most cars all the tools, including the larger ones, such as the jack, pump, wheel-brake, and engine starting handle, are simply thrown into some sort of compartment at the hack or under the seat, where nothing on earth short of wrapping them all up in hessian and jamming them into the compartment will stop them from bumping about on rough roads. Recently what was thought to he serious looseness in the rear shackles was traced to this cause. , In cars of good quality it is customary to provide clips to hold these bulky tools against the walls and floor ot the tool compartment, and ip some cases the admirable scheme is adopted of housing them in the space between the engine bulkhead and the instrument panel, where they are instantly accessible when the bonnet is lifted. This is the best arrangement of all, and is one which could be adopted by manufacturers of production types. The cost would be small, and the convenience of the idea would be greatly appreciated by motorists.

Whatever policy is adopted, however, manufacturers should study the tool-kit question more than they do. giving it better accommodation and improving the quality of the various implements.

PROPELLER SHAFT

It is not a difficult matter to remove the propeller shaft, the usual method being to uncouple the rear llange and slide _ the shaft out of the front universal joint sleeve. When replacing, in the case of Spicer type joints, it is most important to' line up the arrows stamped on the sleeve and shaft. Should these be difficult to locate, painted oi-er, or not provided in manufacture, the rule is to replace the assembly with the outer trunnion of each joint in the same place. Rough action, high speed, vibration, and excessive . wear, are then rarities. Do not paint the outside of the spherical casing.

CRACKED WINDSCREENS

There arc many motor cars with cracked windscreens or cracked win1 his is most dangerous, as the continual vibration of the car will gradually loosen the glass until a sudden stop or slight collision in traffic, will shatter it. Driver and passengers may then receive serious cuts from fragments. It is not very expensive to have a new windscreen cut and fitted, and it is well worth the money as an insurance against accident. Although unshatterable glass is expensive compared with ordinary plate glass, it has obvious advantages which make it highly desirable. In several countries legislation has been passed prohibiting the use of any other type of glass in motor vehicles*

WHY AND WHEREFORE Of GARBURETION

The modern method of delivering petrol to the carburettor by means of a pump demands the correct adjustment of the fuel pump to ensure that the fuel in the float chamber is maintained at the correct level. If the delivery pressure is too high, this will tend to depress the float, thus artificially raising the level. As a result, the mixture will be enriched to the detriment of economy. A check of the fuel pump pressure, by means of a gauge, will often indicate the reason for a low mileage per gallon, when other avenues for improvement have failed. Carburettor.—The function of _ the carburettor is to mix fuel and air in the proportions required by the engine under the varying conditions of speed and load.

Considering petrol or gasoline as the fuel, the correct mixture ratio for complete combustion is 15 parts of air to one part of fuel by weight. In other words, completely to burn 11b of fuel, we require 151 bof air. As would be expected, the mixture ratio which allows for complete combustion also will give maximum economy. Although the above air-fuel ratio (15-1) will give maximum economy, it has been found that a richer setting, approximately 13-1, is required for developing the maximum of power. The reasons for this apparent anomaly are the design features of the engine itself, and the different speeds of combustion in fuel-air mixtures of varying composition. To ensure satisfactory fuel economy and a high power output, some compromise must be made between the airfuel ratios giving maximum power and maximum economy. A sutable compromise for average conditions is an airfuel ratio of 14-1.

The effect of variations in air-fuel ratio can be summarised briefly as follows:

(1) The economy (or miles per gallon) of an engine increases as the airfuel ratio increases from 1-1 to 15-1. As the air-fuel ratio increases still further, the economy is reduced. Therefore no advantage is gained with mixtures leaner than 15-1.

: (2) Power increases as the air-fuel ratio increases, reaching a maximum at approximately 13-1. Further leaning of the mixture causes a slight falling off in power up to 14-1, thereafter the power falls off rapidly. . Nowadays the air-fuel ratio supplied by a carburettor is measured by means of an exhaust gas analyser, of which the Engelhard Air-Fuel Ratio Analyser is a well-known example. We are not concerned with the theory of operation of times instruments, as long as they do their job accurately in indicating the mixture strength. The exhaust analyser continuously draws a sample of exhaust gas, automatically analyses it, and indicates the air-fuel ratio by the position of a pointer moving over a scale. These instruments are calibrated originally by means of actual chemical analyses of exhaust gases from an engine in which the mixture strength can be varied at will.

The analyser, therefore, provides a reliable and infallible means for checking carburetion. It has the further virtue of eliminating, to a great extent, the human element in this very important phase of motor tune-up. Provided an auaylser of a reliable type is used, an expert and detailed knowledge of carburettors is unnecessary. An understanding of the fundamentals of carburetion, coupled with an appreciation of the necessary air-fuel ratios required for power and economy, places the operator of an exhaust analyser in a very much superior and more efficient category than the mechanic who continues to use trial and error methods, or who relies only upon his experience to guide him. Depending upon the equipment available, a definite procedure should be drawn up and adhered to for all tuneup jobs, excepting in those cases where the fault is a single one, and readily is apparent. The advantage in adhering to_ definite procedure is that the work is carried out in a logical sequence of operations, which prevents a fault being overlooked, and moreover demonstrates to the owner the thoroughness of the service given. A further advantage lies in the time saved by the tuner knowing exactly what to do next, and where to lay his hands on the necessary tools.

TIGHTEN SPRING BOLTS

Few parts of a car are subjected to so much stress and strain on a long tour as the “ U ” bolts which hold the springs to the axles, and cine to vibration and stretching of the bolts the nuts are apt to loosen. It is particularly important to take a spanner to these bolts at the end of a hard country run extending over some hundreds of miles and see that they are thoroughly tight. At the same time the spring shackles should be examined and any side play which has developed removed, though it is important not to make them too tight, as freedom of movement is essential.

If tightened right up the spring leaves will not he able to flex, and one or more broken leaves are almost certain to result.

HAZARDS OF THE MIGHT

It is fear that keeps a large number of motorists off the roads at night —fear of the dark; fear of the dazzling beams from the headlamps of approaching cars ; dread of the risks they run when blinded by brilliant lights; dread a J®° of the nervous strain of peering ahead trying to see what obstacles may remain beyond the range of the headlei nips. Have your headlamps working efficiently. Have them adjusted correctly to prevent dazzle. On a car properly equipped for night driving none of these fears need arise. It is seldom convenient or desirable, especially in cold or wet weather, to drive with the windscreen open; yet at points where the risks of night driving are greater than usual, such as an ill.city street, it will be found that visibility can be greatly increased by opening the screen. The improvement

is all the more noticeable if the glass is coloured in any way. The great thing, however, is to avoid a vertical screen, for this will reflect straight into the eyes of the driver the rays frofh the lamps of an overtaking car and of the street lights.

Strain in night driving can be reduced to almost infinitesimal proportions by keeping the speed down. Far too many motorists expect to put up the same speed at night as in the day time, and they are always forcing themselves ot drive faster than they really want to. They are always trying to see just beyond the range of their headlamps, and are for ever on the qui vive with the foot ready to dart to the brake pedal should some unexpected obstacle arise.

DOOR DANGERS

PROPER CLOSING ESSENTIAL Motorists whose cars have doors hinged to the central pillars should be very sure that they are properly closed before starting, and they should not try to open the doors while the car is in motion. Recently a passenger in the front scat of a sedan car of moderate size which had the doors hinged in this manner noticed that while the car was travelling at 40 miles an hour the front door on the driver’s side was on the first latch. Ho directed the driver’s attention to this, and the driver opened the door, with the intention of slamming it. The wind created by the speed of the car wrenched the handle of the door out of the driver’s hand and swung the door wide open. The huge “ air brake ” thus formed by the open door slewed the car right round, and only by quick action was the driver able to control the car and bring it out of its skid. Such an occurrence could easily lead to a serious accident. Many front doors have been wrenched off their hinges because a motorist has started and accelerated rapidly, not knowing that one door was not properly latched. The sudden movement lias thrown the door wide open, and it has struck some obstruction, such as a post or another car.

MOTOR CYCLING

A.A. (OTAGO) FIXTURES April 20.—Monthly meeting. April 24.—Treasure hunt. May B.—Slow hill climb. May 18. —Monthly meeting. May 22.—Paper chase. Juno s.—Sporting trial. June 15.— Annual meeting.

TOLD AT THE WHEEL

Magistrate; “ What have you to say for yourself? ” Prisoner: “I s'ay I wish I was in a place where there were no traffic cops.” Magistrate: “Granted. Twentyone days.”