MOTORDOM

Greymouth Evening Star, 20 January 1939, Page 9

MOTORDOM

NEWS OF THE ROAD

(By

“Gearbox”)

OVRDRIVE DESIGN.

INTERESTING DEVELOPMENT

Technically, one of the most interesting developments of the c years has been the- auxiliary ovcidißc gear, by which a motorist can so iai.-c the final latio between engine and road wheels, that engine revolutions drop by about one-third tor any giien road speed, and important savings arc made in fuel consumption and cylinder wear, while the car in operation becomes very much quieter. Naturally, this high gear impairs acceleration and pulling power, but when cruising at fast speeds in level countiy it, has proved itself an undoubted boon. There are two ways in common use of arranging this overdrive, the most popular being a planetary arrangement behind the gearbox, engaged and disengaged automatically by centrifugal force. This has recently been medilied so that a driver can disengage it at any time without having to allow the road speed to drop to 30 m.p.h. or thereabouts. Ihe other method is a two-speed rear axle, under the direct manual control of the driver at all times, while the driver can use each of the three forward speeds without altering the back axle ratio. That is to say, the car can be started from rest in the normal manner by running through the gears, whether the high ratio is engaged or the low one. However, about two years ago, when overdrive first became prominent, a suggestion was made that a logical way of arranging the extra high ratio for cruising, would be to build a four-speed box in which third speed would be direct drive and equivalent in ratio to the normal top gear of a three-speed box. Fourth speed’ would be geared up ratio which could be held in reserve for fast running on level country. It was stated that this would avoid some of the complications of the other methods and would place the overdrive under the direct control of the driver, an extremely desirable feature in certain circumstances.

It is therefore intel eating that this method has been adopted for the 1939 model of what probably is Great Biitain’s finest sports car. As this is a vehicle 'which sets the fashion hi many respects, it will not be surprising if its example is followed in other makes.

FRONT TYRE WEAR. A most important preliminary to any projected long distance tour is a thorough “vetting” of the car to see that everything is in order, ami in this process, examination of the front wheel alignment is the first essential. On city blocks, a slight misalignment may pass unnoticed in its effect on tyre wear, but w’hen the car is travelling fast on stony, winding country roads, this inal-adjustment will soon become apparent in the rapid scrubbing away of the tyre treads. The cause of this rapid wear will be seen from the torn appearance of the rubber. In exaggerated cases, it is easy enough to wear out a pair of new tyres within 2,000 miles of driving, so that the great importance of wheel alignment is obvious.

But it is of equal importance that the tyre pressures must be maintained at the correct figure, and it should not be forgotten that modern balloon tyres lose their pressure fairly rapidly. if long distances are covered day after day, it will be wise to test the inflation at least every two days.

With regard to this, the loading of the car must be considered. If, for instance, a pressure of 261bs is right for normal running, this should be increased to 281 b, and even perhaps to 301 b at the back, if the car is loaded with five people and their luggage.

On the other hand, the pressure must not bo put up too high, because this will bo followed by wheel spin on corrugated sections, and consequent excessive wear, while the tyres, will not have sufficient rubber in contact with the ground, and will tend to wear down the centre line.

At the present time, when very hot days may be expected, fast running cn country roads will produce so much heat within the tyres from a combination of internal friction and the temperature without, that tyre pleasures will rise by air expansion by three or lour pounds. This is another factor to be remembered when inflating them.

COOLING SYSTEM. With the advent of hot weather special attention should be paid to the cooling system on the motor car or truck: Overheating through shortage ot water in the radiator, or through a defective fan, might lead to seizure or other serious damage in the engine. The radiator core requires periodical flushing to remove scale and dirt which lodges in the small water passages, and old hosing connections should be renewed before the inside rubber becomes perished and swollen. To flush radiator first drain off water by unscrewing radiator tap; then insert nozzle of hose in top opening, and allow water to flow through for a few minutes. Better results may be obtained by forcing water through the core in the opposite direction to its normal flow. This may be done by removing the lower radiator hose connection and injecting water under pressure in the radiator outlet. If the core has become plugged, fill the radiator with a solution of washing soda and water (about lib of soda to live gallons of water), run the engine slowly for a lew minutes, and drain off; then flush out thoroughly with hose and till with clean water.

Do not pour a large quantity of cold i water into radiator when w;it<‘r level is low and the engine hot. otherwise clacking of the cylinder head may follow. It engine is running hot through lack of water, pour a little cold water into radiator slowly, so that the fresh stream may have time to gain heat Iw-t'ors it leaches the engine wall channels. Grease and oil should be kept from' fan belt. If belt, is loose enough to cause slipping its tension should be adjusted, without making it too tight.

CARE 01 FINISH.

GOOD POLISH NEEDED.

All of the sheet metal and body meta) on cars is protected from the formation and spread of rust by a Lon derising process. Yet, if the tinisli is scratched or bioken from the surtace of the metal and the surface left exposed to the elements for an indefinite period, rust may form eventually and spread under the paint Him. Therefore, it is important that any scratched or broken places in the finish be touched up as soon as possible.

No paint will last forever, and the greatest factor to eventual paint failure, normally, is certain light rays. Therefore, whenever possible and practical, a car should be kept under cover, when not in use, to prolong the life of the paint. The result, of these light, rays, which eventually break down the linish on any car, is indicated by what is commonly known as chalking.. This is the normal condition common to all colours, but naturally more severe with some colours than others. Consequently it is only natural to expect that more frequent polishing and cleaning operations will be necessary on colours that are most affected.

The selection of a polish must be carefully made and only that used which has been proven satisfactory. A liquid emulsion polish is recommended provided it is free from acids and alkali, and the occasional use of an abrasive paste polish is satisfactory, if directions for applying are carefully observed. If a linish is given the proper care, it will be washed often enough to keep it free from dust and road scum, and then only with clear water, either lukewarm or cold, applied with a sponge. A soap may be used providing it docs not contain a strong alkali and provided the surface of the car is thoroughly rinsed immediately after the soap is applied. It is important that a car should not be washed or polished in strong sunlight, as this will contribute to water spotting and staining, which are difficult to remove.

The linish may bo damaged if the car is parked under trees exuding sap, under building drains, or close to manufacturing plants producing acids or alkalis. Damage resulting from alkali and acids in the air can usually be identified by stains, winch may be irregular in shape. The colour of the stain will depend on the character of the substance causing it. These stains can be removed, in most cases, by the use of au abrasive paste polish, followed with an emulsion polish. But if such stains are allowed to remain on the linish for any considerable length of time, it may not be possible to remove them and refinishing will be necessary. Tiny specks in the finish, which may bo white, red, yellow, or brown, result from the particles in the air settling on the linish and tlwsn embedding themselves in the paint lilni after exposure to light rays, dew, etc. If not allowed to remain too long, these specks can be removed by the use of an abrasive paste polish, followed with an emulsion polish. Cold weather operation requires that care be taken with the finish because of the damage which may result from anti-freeze preparations being spilled, or from chemicals. In the event of either of the foregoing things occurring the car should be thoroughly washed as soon as possible to prevent any results detrimental to the linish.

WHITE LINES EXPERIMENTS. From reports from overseas it is evident that earnest endeavours are being made by traffic authorities in many countries to bring about greater safety on the roads, largely by the use of white lines, such as already are adopted on most of the main highways in Victoria, though with some variations. One experiment which is reported to be exciting a good deal of interest is being carried out on a busy English road, the Kingston By-pass, and is described in a recent issue of the ‘'Autocar.” Briefly it is explained, in an endeavour to create a sort of "no-man’s land,” the single white line down the centre of the road is being replaced by double lines 3££t apart. The experiment is being made for points at which visibility is cut down to something less than 500 ft, and' the idea, simple though it is. should prove effective in minimising the risk of head-on collisions. Unless the visibility ahead is clear for some hundreds of feet tiespassing over the white line on high-speed roads is a dangerous, but often-to-bc-observcd practice. The two lines will, it is hoped, exercise a strong deterrent effect. The white-line system of directing traffic is applied in various ways. For example, in America a dangerous corner may be indicated by sudden waviness of the normally straight line. But the painting of white lines is by no means a cheap process, and in bad weather the line very soon needs renewing. The cost has to be closely considered.

Another interesting experiment in road safety is being carried out in England by the Epsom and Ewell Council. About half a mile of roadway is being widened from 20ft to 44ft. Alongside the white kerbstone on each side of the road will be two 10ft strips of brick-red indelible concrete. Inside these there will be two further 10ft strips of white concrete, and running down the centre of the road another strip of red concrete 4ft wide, fl he total cost is estimated at £7.000. It is hoped that traffic will keep to the red and white side lanes and regard the central coloured strip on the crown of the road as a "no-man s land.” In this way the road will be similar to a dual carriage-way separated by a grass verge, with the ad-

ditional advantage that the "verge" can be used lor traffic in an emergency. The two-colour roadway, it is added, should also assist night driving. It the scheme is a success and accidents are reduced. I he other roads in tlis district will be similarly treated where possible. CAKDIi AL PF.I’ 1 CIFLEA It has besoms customary to regard 'the modern car as almost fool-prbof As a result one or two cardinal principles of driving, which years ago received publicity, have been overlooked

lately, although they still arc as important as they were previously.

Older motorists have, never forgotten these points and still employ them in modern cairs, but, from the reports which have been received concerning clutch and gearbox trouble, it is evident that, a number of motorists who have begun to drive within the last two or three yeais, are unfamiliar with those principles which have a bearing on the transmission. There is, for instance, that almost elementary rule concerning the clutch that, once it is engaged, the foot should be removed from the pedal. If the new motorist will lean down and press the clutch pedal by hand he will find that there is an inch or two ci' fairly easy movement, before the full icsistam.e of the clutch spring is tclt. 'J ills free movement is put there (•elibeiatcly, because within its range, the forked member within the clutch bell housing is not in contact with the clutch throw-out bearing. It is only when the resistance of the main spring is felt that this fork connects with that bearing. .