MOTORING

Taranaki Daily News, 14 September 1934, Page 11

MOTORING

“KEEP TO THE LEFT” DISTANCE BETWEEN CARS. NEGLECTING THE REGULATIONS. (By “Spotlight") Some regulations more than others appear to, be. honoured more in the breach than jn the observance. “Strangely enough the , first simple rule of th? road, that. of keeping strictly to . ffie left,.not-only on the open road but in the city, is most neglected,” stated the Canterbury Automobile Association in a safety-first- message issued to motorists and other road users in 1932. One can hardly record an improvement in this connection during the last two years. ' There still appears to be a tendency to hug the .crown of’ the road. One needs little imagination to visualise the effect on traffic of this tendency. If vehicles keep to the middle of the road, overtaking vehicles are unable to. pass witho.ut bejng forced on to the incorrect side' of . tlte road right in the path of oncoming, traffic,. Unnecessary risks are encouraged. The “keep to the left” rille js one that should never be broken, particularly by slow > moving traffic. It;, is incumbent on all. drivers to make the safest and most 'proper use of the road, and •an - adherence' to the first law of motoring would considerably eliminate the possibility'.’of accident Another possible source, of danger is the tendency to keep ■ too close to the car in front, with the result that a sudden stoppage may cause a rear-end collision- A driver is, at all times, expected to give a signal when he intends to stop. A motorist travelling closely on the -.rear of' a car has not, in. the case of ah emergency, time to give the signal end check his car, with the result that not only does, he take the risk of coming into violent contact with the car ahead bpt also he is subjected to the likelihood of being rammed from beDistances are very deceptive, and no set rule can’be laid down as to the distance cars should keep apart. The ability of the driver and the particular car concerned are important factors in helping a driver to determine the “safety distance.” ■ ’ •' < In this connection interesting data, has been compiled by the Pennsylvania Highway Department (U.SA.). This sets forth the following margins between vehicles travelling in a single line op narrow roads at varjous speeds: At 30 m.p.h. the distance separating the cars should be 71ft., 35 m-P-h. 90ft., 40 m.p.h.. 113 ft., 45 m.p.h. 138 ft., 50 m.p.h. 167 ft., 55 m.p.h. 198 ft, 6Q m-P-h- 233 ft. These allowances ape based on a singl e 10ft of lane of > pavement, and figured at peak, traffic loads. Imagine also a road just wide enough for two lanes of traffic, with a continual stream of cars on each side.. Then one has an idea of the conditions, where the stopping margins specified should be allowed as a safeguard against rear-end collisions. On wide roads a smaller margin than, say, the 71ft. specified at a speed of 30 m.p.h. may be safely .allowed on. account of the greater flexibility .permitted , traffic. Although the Pennsylvanian .calculations are hardly applicable to Taranaki conditions they can be used as an indication to , reach a definite decision as io the required distance for stopping any particular vehicle in an emergency. HAND SIGNALS NOTIFYING DIRECTION CHANGE. ADVICE OF ASSOCIATION. “A distinct laxity’ is still noticeable in ffie manner ■ in which ail< l others' give signals of intended change of direction,” says.the Canterbury Automobile Association in its latest safety first message to motorists. “Some of the motorists show a marked reluctance in< givirg proper hand signals. Mapy drivers actually start. to turn their cars before they give a hand signal, and when they do so it is in a half-hearted way which. is po guide to a following driver. It is quite obvious that many, drivers who are neglectful with their hand, signals are also neglectful of the rear-view mirror. They will not go to the small trouble of consulting the rear-view mirror. They seem content to give as much trouble as possible to the driver of the car-'behind. • “It is the boupden duty of all drivers to sound the horn before making a change of direction. The horn is a warping to following traffic. .When that warning has' been given the plain display of the hand and arm signal should be made. To dangle one’s fingers over a half-opened window is. not the correct method of giving a signal. ■ Drivers who think that is proper signalling are poor drivers, and discourteous as well. “Cyclists are outstandingly lacking in traffic sense. when it comes t< the protection of themselves by giving hand signals. An overtaking motorist cannot guess when and where cyclist is going to change his direction suddenly, yet many cyclists take enormous risks in this matter. Many accidents would be avoided if motorists and cyclists applied ordinary rules of common sense to their conduct in traffic.”

COURTESIES OF THE ROAD CHANGE THAT COMES OVER MEN. NORMAL MANNERS DISCARDED. I (By “Spark Plug.") , Having covered a mileage of over 300,000 in my car I can safely claim that I have had some experience in driving on New Zealand roads. T have had two minor accidents, at the same time I have had many close shaves. I do not profess to be a so-called “expert driver” and I always play safe by taking no undue risks. When I have any appointments I leave myself ample time to get to my destination on time, at a reasonable speed. . It is regrettable the change that comes ovei’ motorists when once they get into their cars. Their normal courtesy is shed and they -ppear to become, selfish, self-righteous, obstinate, and incapable of showing the manners. and consideration which are usually second nature to them when not motoring. The spirit of give and take is deplorably absent; each appears to become a self-imposed judge of the driving methods of others, and quick resentment is roused by the action of another Who in all possibility; was doing hjs level best in the circumstances. Take the question of overtaking a slower driver than yourself, you sound youi" horn as a matter of courtesy and safety, yet there is no heed taken by the driver—-he ' keeps on in the middle of the road and forces the driver of the overtaking car to go on the wet clay edge to enable him to pass. This is no exceptional case, but happens every day. It pays every driver to give way when being overtaken by another car. Apart from the lack of courtesy it might easily cause a very serious accideiit. When a car is forced over- on a clay edge a very nasty skid might occur involving both cars in a serious smash. If we could only say somehow to the man ahead, “May we pass please?” his reply would be, “Certainly,” and he would draw over, to his left. In future when you hear the horn of an overtaking car asking you to. please give the driver enough of the road for his car to pass yours safely I hope you will respond to the request. These small courtesies on the road make motoring more pleasant and safer. NEW TWO-STROKE ENGINE A TWELVE CYLINDER UNIT. An entirely new type of power unit for racing purposes lias been ‘ developed in Germany by the Swiss engineer, Arnold Zoller, the inventor of the B.M.W. 750 c.c. motor-cycle, with which E. Henne holds the world’s motor-cycle speed record of 151.8 miles an hour. The New Zoller engine is a two-stroke of unusual design. The crankcase and cylinder jackets consist of aluminium alloy and are cast in one piece, and there are 12 cylinder barrels in two rows of six, in which steel liners are inserted. The detachable cylinder-head casting is designed so that each six combustion chambers serves two cylinders. The cylinders along the right hand side of the engine contain the exhaust ports those on the left the inlet ports, both sets of ports being opened and closed by the aluminium pistons in respective cylinders. The pistons in the exhaust cylinders work directly on the crankshaft, while the other pistons are linked to the connecting rods from the exhaust pistons at the big-end bearings, the angle being so arranged that the exhaust pistons open and close their ports earlier than the inlet pistons. This system is claimed to aid efficient scavenging and to permit a high degree of supercharging. At the" forward end of the crankshaft, driven through gears, are two Zoller superchargers which feed the gas at a pressure of 211 b. to the square inch. The two safety valves on the delivery pipe are set to open above a pressure of 281 b. The 12 cylinder barrels have a bore of only 43 mm. and a stroke of 84 mm., so that the entire piston displacement of the engine is less than 1500 c.c.

Owing to the dual cylinder arrangement it .is possible to feed this engine by supercharging with the.. same flmount of gas that an engine of 6000 c.c. would normally consume. The output of the Zoller engine is claimed to be about 200 horse-power at ‘5500 revolutions a minute, and as it weighs only 2101 b. the power-weight ratio is almost 1 h.p. to 11b. of metal.

When the car is washed with a hose, water often enters the brake drums, and as water acts as a lubricant on the lining the friction will be reduced, thus making the brakes less efficient. Always try the brake after the car has been washed, and if it is found that the water has entered the drums, drive the cai- for a short distance with the hand brake slightly on, to dry off the water. If the hand brake is kept on while the car is being washed it will help to keep the brake surfaces dry. * * * *

It is said that competition in Spain is so severe that some firms are giving away one tyre with every three tyres purchased.

IMPORTANCE OF SPARK PLUGS TYPES FOR EACH ENGINE. HOT AND COLD RUNNING PLUGS. No matter how good a sparking plug may pe it will not give satisfactory service if it is of an incorrect type. Generally speaking, the motorist fails to realise that there can be a great deal of difference between sparking plugs—not only as regards quality but also in the heat characteristics of the plugs themselves. The purpose of this article is to show what are the essential requirements of a sparking plug, and to trace their effects on the operation of the engine. Engines in use to-day vary widely in type from, say the large and relatively “woolly” engine to the small high compression, high speed type. The heat conditions inside ■ the cylinders of these engines vary accordingly. In addition to the different, designs of engine, the conditions under which they are operated, e.g., high speed—a great deal- of traffic driving—or continued heavy haulage, all have their effect on the suitability or otherwise of the sparking plug. No one make or type of' plug has? yet been evolved which will give satisfactory service under'all these varying conditions ?md, in consequence, each manufacturer has to provide a series of different types, each designed to give optimum results when used under a given range of conditions. The two essential factors to be satisfied are:—That the plug shall keep sufficiently hot that it will burn off any oil or carbon which may tend to. form on the insulator; that it will keep sufficiently cool, and it: will not cause pre-igni-tion.

The former requirement' is necessary on account of the fact that carbon is a good electrical conductor and, clearly, jf a layer of this substance is formed over tfie surface of the insulator, a short circuit would result and the plug would cease to fife. Pre-ignition implies that the points of the plug become so hot that they may eventually become incandescent and cause ignition of the charge before the spark fires it. When pre-igpition occurs very high pressure will be imposed on the piston before it reaches its top centre position. There is no difficulty in allowing the plug to become sufficiently hot to bum up the carbon but, unfortunately, the range between ffiis temperature and that at which there is a danger from preignition is relatively narrow. Time also has an influence on the performance of the sparking plug for is desirable that the temperature shall rise sufficiently rapidly to prevent fouling when the engine is cool. The method in which a plug loses its heat is very largely via the following path;, the heat travels up from the centre point through the insulator, through the copper gasket ipto the body of the plug, and thence either ipto the air or cooling water. .The shape and size of the insulator determine the heat range of the plugs for a given engffie <i.e. a.given set: of cooling conditions). It is advantageous that the rate of heat flow away from a plug be such that it balances the heat given to it, causing the temperature to rise to a safe maximum and stay there, i.e., that the plug does not get hotter and hotter as time goes on. A modern trend is to employ a 14 m/m type of plug in certain engines of recent design in place of the more orthodox 18 m/m type. The smaller plug is capable of being made with a wider heat range, that is, it heats up quickly but its temperature does not exceed a given maximum if the car is driven hard. It is useless to use a 14 m/m plug, in an engine made to fit the 18 m/m size, by employing an adaptor, for the presence of the' two threads will ' entirely upset the heat flow from the plug body to the cooling water.’ SELECTION OF SUITABLE TYPE. Racing, and sports car engines develop a relatively much greater amount of power per cylinder than their normal prototypes. Consequently, a greater amount of heat has to be handled by the sparking plugs of these engines. Therefore, it is necessary to use a plug which will get rid of its heat quickly,, i.e., a cool running plug. If .these cars be driven slowly in traffic jt is well-ktown that they are liable to suffer from “oil-ing-up.” This is due to the fact that under partial throttle conditions the amount of heat passing through the; plug js insufficient to raise its temperature to the degree required to’hurn off the carr bon. If on the other hand an ordinary or hotter running plug is used, trouble may be experienced from pre-igpitipn when .the engine is opened up to full throttle. ■ . . 'lt is proposed to give an. analysis of the different factors which can affect the performance of a plug. It is h.°P e d that the information will be sufficient to allow the motorist to decide intelligently for himself whether the plugs he is using are giving him the most satisfactory service and, if not, in which direction a change should be made. Persistent oiling or sooting up is an indication that the plug is operating at too low a temperature (e.g., a.’ sports car type of plug in a touring engine) and a change should be made to a hotter running plug. Pre-ignition or severe over-heating:— Overheating may be due to pre-ignition, which can be detected by a rapid falling off in power after the car has been driven fast for some time. If this condition is experienced, and it is further shown up in rapid burning away of the points, a change should be made to a cooler plug. High compression:—lf your car is fitted with a head giving a higher compres-

sion ratio than normal, it may require a change to a cooler running plug. Hot climate:—lf the car be operated in a very hot climate, a change to a cooler plug may be desirable also. Excess of traffic driving:—lf a great deal of traffic' driving is. done, especially in a high compression car, then the plugs may keep so cool that trouble from sooting-up .is experienced. A change to a hotter running type of plug will overcome this in most cases. Regular driving at high speeds:-If this habjt be indulged in owing to the presence of modern arterial roads, then the temperature of the plug may. in time become tod hot, although it might give quite satisfactory service under more normal conditions. If a loss of power is experienced, a change to a cooler plug should givr an improvement, but clearly more care must be taken to avoid oiling up when the car is used in town driving. Ethyl petrol?:—The march of progress has been towards higher compression ratio? and, to meet this, the oil companies are marketing anti-knock fuels. The most popular of, this, type are the ethyl petrol? which are now extensively used. These are high class petrols to which a minute quantity of ethyl fluid (which contains tetra-ethyl lead) has been added. When this is burnt there is sometimes a tendency for lead salts to be deposited on the sparking plugs. Whilst these are practically non-con-ductors at normal temperatures, an increase in temperature may result in the fluxing of them on the insulator, under which conditions they may become conductive. If trouble is experienced from these lead deposits—don’t blame the petrol, but change to a cooler plug when no further trouble should result. It will be noticed throughout this article that the terms “hot running’’ and “cold running” have been used, and it is as well to understand the meaning or these with the utmost clarity. By “hot running” is meant a plug which will work hotter than another, i.e., one with a relatively long insulator. Do not confuse this with the term “hot ( plug or “hot stuff plug” which is often used, and is rather a misnomer, since it implies in reality a “cool running” plug for use m a hot engine.