Motoring.

Southland Times, Issue 18822, 15 May 1920, Page 9

Motoring.

(By “Headl'ght.” i

In America the driver of a smoky motor car is always in danger of being ctopjg-d by a policeman and asked (o explain the reason for the smoky condition before the Traffic Court. Tills is r. step that could be taken in New Zealand with benefit to the comfort and health of the city communities. Most of the smoke which we see comes from too much lubricating old supplied to the engine. This may come from having the reservoir too full, that is, with oil above the level indicated by the manufacturer. The remedy would be to draw off the surplus. But the fault may be in the construction, with too much oil fed to the engine even, when the reservoir level is normal. This means lowering the level by altering the splash troughs, or narrowing the, dippers so there will be less splash. In some cases it may be found that the cylinders have worn, or that the piston rings may be gummed with carbon deposit mixed with oil, or they may ha'e lost their original spring. All these things will permit a large amount of oil to work up into the combustion chamber to burn and cause carbon deposit and smoke. The remedy is to have the cylinders rebored or ground and new pistons fitted; or it may

be possible to correct the trouble -with fecial piston rings which take up the wear and keep. the ezcefis of oil from, the cylinders; for gummed rings cleaning alone is necessary. ' Most of the trouble with oil comes when driving at low throttle opening. When touring, there is likely to be very little smoke, as the engine is run, with fairly wide throttle most of the time. When the car enters the city, where there must be much throttling down, ■ there • may be trouble with smoke. The reason is that with a closed throttle the gas drawn in does not fill- the vacuum in the - combustion chamber, and this draws oil past the pistons. The same thing comes when the engine is running idle -at the curb- for some time, as the chauffeur put? it, oil.” The trouble is likely to occur more in cool weather than when it is warm and vaporization is perfect, for the engine is more often kept running so it wUi not cool too much, or freeze. Running idls also causes the carburetor to load up and dense black smoke is the result when the engine is started. Smoke caused by excess of gasoline may be distinguished by being black, while that from excess oil is blue. There is always steam issuing from the exhaust, and as soon as it strikes cool air it is white. One of the products of combustion in the cylinders is water, which is vaporized and passes out with the exhaust, becoming steam. It might be suggested that, since there are smoke offenders, the police go to school to an expert in gasoline combustion, to learn the ways of smoking cars and how to know the chronic offender from the one who is merely the victim of cold weather and an engine that pumps oil. One of the interesting recent motor developments in America is the wheel now being worked out experimentally by a large aluminium castings company in t&at country. The wheel is a one-piece aluminium alloy easting made in either hoDow spoke or disc type designs. Extensive road and laboratory teste to date indicate that the new wheel, unconventional in design as well as in material, possesses all the desirable features claimed for- the wood or steel wheel, and in addition enjoys certain very important advantages common to neither of the existing types. The aluminium alloy wheel weighs about half as much as any other wheel on the market. It will therefore, decrease the weight below the springs (the unsprung weight) very materially and at the same time should guarantee ample strength. The importance of reducing the weight of the unsprung portion of the chassis on motor vehicles is not generally appreciated. There is, however, a wide divergence of opinion among the leading automobile engineers as to the proper ratio between the sprung and the unsprung weight. Some hold this ratio to be 10 to 1, while others place it higher or lower as their opinions may be, hut it is generally admitted that a great deal is to be gained by saving unsprung weight in the following respects: Economy in tyre wear, increased carrying capacity, improved riding qualities, economy in fuel consumption, better acceleration. It is obvious that when a motor vehicle is travelling at fair speed over an irregular road, there is a tendency for one or both wheels to break contact with the ground immediately after passing over some obstacle. If one rear wheel leaves the road it is free to rotate at any speed which the engine may induce, i.e., at any abnormal rate of speed. Consequently, when the wheel again comes into contact with the road a certain amount of slip must occur until its speed is made to conform with that of the other wheel. The slip Is very detrimental to tyres, causing severe road friction and abrasion. The rebound or tendency to leave the ground is materially levs with light wheels. All the arguments advanced by the advocates of lighter oars in respect to economy of operation apply • with equal force to the car equipped with ■ aluminium alloy wheels. There is no doubt, that a lighter wheel forecasts im-. port.ant paving in fuel, as well as better • acceleration and more comfort, j One of the most satisfactory development* to hs traced in some of the new cars coming .dong is the appreciable reduction in chassis weight without decreasing the strength of the whole structure. In some oases scientific designing has actually brought about an increase of power with a decrease in weight. If the body builders can cany mi this good work, we shall have cars lacking nothing nothing in comfort, good appearance and durability, and yet considerably lighter than the pre-war models. The saving in petrol, tyres and general upkeep, coupled with the better running of the new cars, should well justify the prices which are asked for them. One Ircquently hears remarks in reference to weight reduction, but it is forgotten that weight reduction on scientific and safe lines is a costly process. Taking the factors of passenger comfort and speed into account, it is evident that weight reduction can only be fully and safely practised on the very high-grade cars which cost considerable sums. When a leather-to-mefcal cone clutch gives trouble in the nature of slip, it is possible that a ridge has formed on the extreme outer edge of the cone, which prevents the clutch from fully engaging. This ridge can be removed by a rasp or a sharp knife. It is as well, at the same time, to withdraw the clutch as far as possible, when the leather can be scraped clean and washed with petrol. Perhaps the best dressing for the leather is made up of two-thirds rollan oil and the other third of the quantity made up of two parts of caster oi! and one of paraffin. Attendance at the Motor Boat Show, lately on at the Grand Central Palace (New York), showed that interest in the sport did not die as the result of the war, during winch motorboating as a sport languished, hut instead that is received wonderful impetus as a direct result of the - xperience many young men gained in naval service. Practically every exhibitor at the show had talas to tell of inquiries made by men who first came to know of die enjoyment and sport offered by power craft during their service afloat in the : ervicc of Uncle Sam (says an American paper). Many of these newcomers into sport of motorboaiing have placed orders for craft ranging from diminutive dories to the largest of sea-going power cruisers, and a majority of the new owners 1 1 avo had far more experience in the handling of motorboats, under all sorts of weather conditions, than the average new owner prior to the great war. It is estimated d <u„ r . •; r e 350.000 motorboat enthusiasts in the United States, and the crafts . ’ i • the Grand Central Palace in th- Fifteenth Annual Show indicate a general demand for increased seaworthiness, comfort and sightliness in design, quite in keeping with the increase in the number of owners. While there are few, if any, radical changes in design, still the effect of the experience gained during the war has been to develop craft of a much more seaworthy type than were generally to be found a few years ago. The high cost of gasoline is responsible for widespread interest in other fuels. Several motors on the market burn kerosene, or either gasoline or kerosene, but one of the best, prospects in new fuels for small boats seems to be crude oil. On the Pacific Coast this fuel is especially popular. Technical experts cite impressive instances of the saving in fuel expense afforded by crude oil. In one case aji eight horse-!>ov.-er. single cylinder gasoline motor consume;! an average of a gallon an hour, the gas costing 30 cents a gallon, while a seven and one-half horse-power crude oil motor, single cylinder, burned two quarts of crude oil at a cost of 8 cents a gallon.