MOTORING & MOTORISTS

Evening Star, Issue 21655, 26 February 1934, Page 13

MOTORING & MOTORISTS

[BY RADIATOR.]

LIGHTING-UP TIMES To-day 8.3 Tuesday 8.1 Wednesday 7.59 Thursday 7.58 Friday 7.5(5 Saturday 7.55 Sunday ... 7.53 1934 AMERICAN CARS INDEPENDENT SPRINGING OF FRONT WHEELS In a review of new things in connection with the American cars of 1934 a prominent motor engineer refers to the matter of independent springing of the front wheels. The idea of independent springing, lie remarks, is not new, because there has always been a demand for easy riding, especially in regard to cam with short wheelbases. , Manufacturers outside America have used forms of independent suspension for some time, md as long ago as 1913ui number of small cars in the United States were so equipped. While- better riding quality was the aim some years back, the need for separate wheel action has been greater since balloon tyres arrived. Such tyres, he says, upset front-end stability and brought in a host of troubles which called for correction after correction as the years went on. Now, with still faster and softer tyres, with the addition of softer- front springs, freedom from shimmy, tramp, and all the other names given to front wheel and steering actions and reactions, the need for a'radical move has given independent suspension. Springs are usually thought of as having to hold up the car, but they have to do more than that. In the rear in nearly all cars they also transmit the drive and absorb the rear axle torque The, car is pushed through the rear springs. Sometimes they are reslieved of extra work, as when a torque tube.or rod is used. In all cars with semi-elliptic front springs the latter have to support the frame, take brake torque, and keep the front axle in place. Obviously, with all manner of forces acting on them they cannot' be made - too soft in action; rather they must he fairly stiff, hence not so easy riding. Moreover, -whatever movement the

Brief accounts of holiday trips, roads, and places of Interest are invited for this column.

front sprints impart 1 to the frame has its effect on the rear springs by lifting up the front of the frame and compressing the rear springs. What one wheel does after a bump means some transfer of movement to the solid axle, the steering, and perhaps the other front wheel. When the front wheels are independently sprung each spring has its own wheel, and what it does is its business almost exclusively, so all the spring has to do is hold up its end of the frame, riven the shock absorbers can he set once and for all, whereas with semi-elliptic springs and the previous designs the spring varied in “ rate," depending on whether they were- oiled or rusty, because the leaves slid over one another. With independent suspension the shock absorbers do not have to change their action, depending upon interleaf friction. There is from four to six inches of wheel movement with coil springs, against a limit of mbout 3in •before bottoming with the former designs. Here he brings in a “ but.” He says that with independent suspension a lot more is going to be heard of tyre scuffing and about wheels slanting on turns. However, what faults the various independent systems may have are minor compared with what took place before. Tyre treads have been designed to take care of any added wear from scuffing. RADIO FOR MOTOR PATROLS A report on tests that had been carried out with short-wave radio sots in the cars of motor patrols was made by Mr W. A Sutherland, secretary of the Wellington Automobile Club, at the half-yearly meeting of the North Island Motor Union. He said it had been decided that in view of the service which could be given, the expenditure would not be warranted at present. 'The proposal might, however, be worth reconsideration in. a few years. ROUGH RUNNING Rough running of an engine is often caused by wear or faulty adjustments, which result in differences in ignition timing in the cylinders, and is specially noticeable with modern engines using high compression pressures. Many such

engines or the multi-cylinder type are fitted with distributors having duplex contact breakers, and unless the owner is prepared to go to the trouble necessary to synchronise their opening by means of test lamps, adjustments arc best made by the service station. Plugs also should bo all of the .same type and accurately adjusted. In the case of cars which have done considerable mileage, the fault may result from uneven wear of the contact breaker cam or distributor driving gears. Other causes which are usually fairly easy to rectify are poor compression in one nr more cylinders, with good compression in others, and inaccurate setting of valve tappets. Detonation and pre-ignition are other causes. If it is the former, it will be reduced or overcome by the use of a loaded fuel or a mixture of petrol and benzol. The latter is indicated when the engine continues to fire after the ignition is switched off after some fairly hard driving. Retarding the sjiark will reduce pounding from detonation, but will not materially affect that from preignition. Roughness similarly will re r suit from over-advanced ignition. A cause of apparent engine roughness is to he found in dry or worn nnivcrsals or tailshaft vibration, while a similar effect is sometimes produced by loose engine mounting. This, of course, does not apply so much to rubber mountings, which, if tightened too much, will cease to he of benefit owing to loss of necessary' resiliency'. One effect of rough running is that it sometimes will be confined mainly to one cylinder. In such cases the pounding, which is especially noticeable at low speeds with open throttle, is easy to mistake for a loose main bearing. Excessive carbon deposit favours the development of local overheating in the. combustion chamber, the basic cause of pre-ignition and of most cases of detonation. Such' overheating does not necessarily mean that the water boils, for it often occurs with the-'tempera-ture of the main water reserve at normal Automatic control of ignition timing will do a great deal towards eliminating roughness. Some engines require constant attention to variation in ignition timing in accordance with speed and load conditions, and this cannot be provided satisfactorily by hand. It is the ease with which automatic control can bo provided with coil ignition which has led to the displacemeht of the magnetic on most modern high-compression

engines, the latest devices adjusting the spark in accordance with both the speed and load factors encountered. THE BEST SELLERS The following table shows the number of cars with sales of fifty or more for the year 1933 in New Zealand: —

TYRE DAMAGE EFFECT OF CARELESS DRIVING The main reason for the great improvement in tyres lies in the construction of the casing, or cord foundation of the cover, and in the better compounding of the rubber tread with toughening agents. There arc still occasions, however, when, through careless driving or mishap, tyre troubles subsequently result, perhaps a considerable time after the real damage has been done. Many drivers think nothing of striking a kerbside a somewhat severe glancing blow as the vehicle is drawn to the side of the road; probably just before it stops. Such treatment may bring about an impact burst in the casing. At the time, no outward sign of a bruise in the foundation of the cover may be apparent, but after running perhaps thousands of miles, the casing at the point bruised by the impact, may weaken, so that the cover fails prematurely at that spot. The same warning applies to running over large stones, a brick, or any comnaratively sharp-edged obstruction. PRESERVING SPARE TYRE. Many car owners fail to realise that lie life of a motor tyre, not in regular ise, can be nearly doubled by keeping t in a cool, dark place. Tyres not in use, states a well-known rubber com : pany, should not be exposed to light and heat for any great length of time, since deterioration quickly sets in. This advice applies not only to tyres hung up in one’s garage, but also to the tyre on the spare wheel. Thanks to the greater dependability of the present-day tyres, long periods now frequently elapse before the average motorist has need to use his spare wheel, and unless the trye is protected by some form of cover, it suffers more barm through exposure than it would during many miles of normal use. The best plan to adopt in regard to the spare wheel is occasionally to put it

into use, for it is better to wear the tyre out than allow it to perish through deterioration. . HIGH AVERAGE SPEEDS When covering the less interesting parts of a holiday tour high average speed is often very desirable in order that more leisure may. be available for the pleasant portions of the itinerary. Covering the distance in minimum time does not require speed of a racing order, but rather the maintenance of a steady pace, without , lost time.’ Driving at speed approaching the maximum of which the car is capable often results in loss of time, either , through mechanical trouble or driver, fatigue. Good tyres are most important, not only to avoid trouble, but also to ensure safety. Few people realise' that brakes alone have nothing to do with stopping a car;' their power must be transferred through the tyre, as must that of the engine, and an efficient non-skid surface is important. Worn tyres also may conceal hidden defects in •. the casing, leading ultimately to a blowout, which may have serious results at speed. Correct inflation has a considerable influence on road-holding, and this reacts materially on the safe and comfortable average that can be maintained. If corners can be taken slightly faster, for instance, the saving of time in a day’s driving will be considerable. For this reason it is worth while to experiment with shock-absorber.settings until one is found that is satisfactory all round. The best setting for fast driving usually is one that is slightly too hard for. maximum comfort at low speeds, particularly with the friction type of damper. Weight distrbuton is the other important factor for comfortable driving, and it can be effected by the placing of passengers and luggage. If possible have your heaviest passenger in front, and do not place heavy luggage on the rear carrier. The heaviest items are best placed amidships, in the body, and it is best to carry luggage on both running boards, or else to balance it by putting heavier passengers on the opposite side of the car. Correctly-adjusted steering and a comfortable driving position are other factors which contribute to creditable averages by making possbilo longer stretches of driving without, rest or refreshment. CARELESS FILLING The flouting of public safety by motorists who fail to shut off their engines while taking in petrol at garages has been noted by the National Roads and Motorists’ Association of Australia. There have been several instances of late of cars having been totally caught almht, ami one garage was burnt out as well. A slow-running engine will sometimes “ miss ’’ and when it picks up a small quantity of petrol vapour passed through to the exhaust is likely to ignite, causing a flame. This flame near the petrol tank is quite sufficient to cause the spirit vapour to ignite. It

is even more dangerous to leave the engine running on a' small "car. which carries its petrol tank under the bonnet. A spark from the distributor or a faulty high-tension wire are capable of igniting the vapour that collects round the tank when it is being filled.' " - 1 BRAKE TESTING MACHINE A brake-testing machine, which is being operated successfully by Government departments and transport organisations in New Zealand, was tested'in Melbourne recently by officers of the Defence Department and others interested (states the Melbourne ‘ Age ’). It consists of sets of electri-cally-driven rollers, sunk level with the floor, which cause the wheels of the vehicle being tested to revolve. The vehicle’s brakes are then applied, and the retarding action is clearly shown by a hydraulic recording device. This method is a distinct advance on the “ road test ” system at present employed in Melbourne in which the human factor plays a large part, and which largely depends on guesswork. Another advantage is that it clearly discloses distortion of the brake drums and considerably reduces the time required to make accurate adjustments. The machine is known as the Hawson hydraulic brake tester, and it is manufactured by Rawson Brake Tester (N.Z.) Ltd. The difficulty of providing an equitable test of brake efficiency has been one of the obstacles in the past to the introduction of a system of compulsory tests of the safety factors of motor vehicles. The use of such a machine as the Rawson brake tester, which is purely mechanical m operation and which is based on sound principles, should overcome this objection. Q.M.C. LIGHT GAR SECTION FIXTURES March 6.—Monthly meeting.. March 10.—Run to beach races. March 23.—Run to Mjddlemarch. April 4.—Monthly meeting. April 22.—Petrol consumption. May I.—Monthly meeting.. May 6.—Trial to include speed judging and braking. May 19.—Night trial; June 3 and 4.—King’s Birthday Trial. June s.—Monthly meeting. June 16.—Despatch run. October 20, 21, 22.—Labour Day trial.

« Number Percentage sold. of total. Ford ... ... ... 938 25.80 Austin ... 724 19.91 Morris ... ... 464 12.75 Vauxhall ... 222 ■6.10 Hillman ... 196 5.39 Singer '... 189 5.19 Standard ... 178 4.89 Chevrolet ... 120 3.30 Essex • ... 87 2.39 Dodge .... ... ... 78 2.14' Riley ... 61 1.G7 Other cars ... ... 378 10.47 3,635 100.00