MOTORDOM

Greymouth Evening Star, 28 September 1928, Page 3

MOTORDOM

NEWS OF THE ROAD

(By

“Gearbox”)

KEEPING OIL COOL. SPARK SYSTEMS. Motorists must, be particularly inI frosted in the efforts that are being made adequately to coll lubricatiug oil. Thus bearings shall be fed with cool oil instead of lubricant which is at a temperature near or above that of boiling water. It is probably not generally realized that a crankshaft performing reasonably hard work,, say pushing a. cai at o 5 to 40 m.p.h., may reach a tempeiature of 200 degrees. The oil, therefore, must reach practically the same temperature, and in full pressure lubricating sy-stems, the same oil that passes (through the main bearings is carried I onward to the big ends so that the latter are fed with hot, thin, oil.' The Ford, for instance, has retained this system, as by its means the big ends are fed with comparatively cool oil. With the pressure system, the only wav the oil can be cooled is for it to be taken out of the sump and sent through some type or other of cooling apparatus. Late researches into engine operation have demonstrated a real need for reducing the oil temperature. Some makers have already increased the size of their sumps, and ribbed them heavily, so that the'heat is carried away by the rush of air underneath the car. While the system helps to cool the oil, it does not go far enough, and manufacturers both of cars and of accessories are busy on the job of developing thoroughly efficient cooling apparatus. One system which has been developed recently called for two independent pumps, one Supplying the bearings while the other forces oil through a radiator placed at the back .of the water radiator so that it participates in the rush of cool air thus induced by the fan. The cool oil is fed back to a wall from which the bearing pump takes its supply. The super-charged Arrol car has another system whereby the oil is contained in a tank between the front dumb irons, where it is fully exposed to the flow of cool air. Another* big maker —Peugeot—has adopted a forced system whereby oil is taken through the radiator from a by-pass valve. Most racing cars are now fitted with oil cooling devices of some form or other, and it is only a matter of very short time before passenger cars will be fitted in a similar way. Experiments . with the Peugeot system in operation on a fast touring car showed that whereas the working temperature of the oil without an oil 'radiator in operation was 195 degrees, th" temperature was reduced to 100 with the radiator in action. Furthermore, and most important, it was found that when the oil temperature was kept low there was a marked decrease in consumption, amounting from 15 to 20 per cent. The importance of keeping the oil cool when the engine is under pressure can be gauged when it is considered that the strength of white metal decreases quickly after a temperature of 200 degrees is reached, and that at 300 degrees it becomes fluid. In a country such as New Zealand, where in summer engines run under very arduous conditions, this matter of oil cooling is of great importance, and developments will be watched with keen in terost by motorists who are more than mere drivers.

VALVE KNOCK.

NOISES IN THE HEAD.

Overhead valve engines are admittedly noisier in operation than engines which have their valves at the side, but the adoption of the covered-in head has reduced the clatter from the push-rods and rockers considerably. In order to securp the maximum of silence from an overhead valve engine, the clearance has to be very small, find in addition has to be checked every few hundred miles to ensure that no valve is riding. On this account many owners make their clearances a good deal greater than the limit of safety, and, in consequence, their engines make no small amount of noise in operation. Strangely enough, however, it is not the valves as a whole that make the objectionable noise, but nearly always one or two only. With a little care the offenders can be traced, and by a reduction of the clearance the whole of the valves can be made even, and quietness of running gained. The method to be used in detecting the noisy valves is quite simple. The engine must be kept running at a moderate speed with the valves exposed. The blade of a pocket-knife is then pushed between the tappet and the rocker until all the play is taken up. It will bo found that the objectionable clatter will disappear when the knife is pushed under the offending rockers. The engine should then be stopped and the clearance of the valves perfected.

THE AUTOMOBILE.

WHO WAS THE INVENTOR?

The appointment of a. committee by the President of Austria to collect funds for the erection of a memorial to Siegfried Marcus, Austrian engineer, revives again the question: “When invented the automobile?” The answer to the question depends very much upon how one chooses to define the word ‘automobile,’ ” says the Denver ‘Post.’ “If one means a vehicle capable of self-propulsion, one can go back as far as 1770 to find the first automobile, for in that year Nicholas Cugnot, a Frenchman, designed and built two road carriages that propelled themselves .by steam. Oliver Evans, a Philadelphian, achieved practical success in the same way a few years later. ‘Steam Wagons’ occupied the attention of many inventors during tho first quarter of the nineteenth century 911 the Continent and in England particularly. Apart, from the fact that they had no hors'es hitched in front of them they did not resemble the automobile as it is now known. The first vehicles that might be regarded as the lineal ancestors of the modern automobile appeared in the United States in the early ’nineties. And from these machines, so scorned and mocked at in those days, have come the superb automotive creations of to-day. It may be that the automobile was invented in Europe, but certainly to tho United States must go a large measure of credit for its development into the most useful medium of individual transportation the world has ever known,”

TROUBLESOME CLUTCH. THICK OIL AND SLIPPING. Among the many troubles which are liable to upset the equanimity of an owner are those incidental to'the clutch. In the last five or six years very great improvements have been made to this important unit of the car, but even the best of clutches will slip, and when this occurs a good deal of damage can be done if the job of correcting the trouble is not set about in the proper manner. In nearly every case where such slipping is experienced it is due to . an overplus of thick oil finding its way on to the clutch faces. The remedy for this state of affairs is to clean the excess oil away. This can be done by means of thoroughly swilling the clutch out with petrol. It is advisable to use kerosene for the first flushing, as this seems to get deeper into the plates and allows the petrol to make a cleaner job. In most cars there is an inspection plate in the top of the clutch housing, and this will have to be removed. While an assistant pushes the clutch out as far as it will go, about a cupful of kerosene should be squirted, by means of a long-necked oil-can, between the plates. The clutch can then be let in and the engine started. With the clutch running at a medium speed, the centrifugal force will throw the kerosene off the plates, carrying a large percentage of the excess oil with it. The same process can then be repeated two or three times with the petrol, using about a cupful each time. With a dry plate clutch no further work will be needed, but in the case of the metal unit a small amount of light oil, such as “3 in 1,” should be injected between the plates. After the clutch has been cleaned in this manner, it will quite often be found (that slipping still occurs. This is due 'to an entirely different cause. The clutch plates being clean, they require the rearward travel of the clutch pedal to be greater before they arebrought into close contact. The clutch pedal, will either be found to come back against the footboards or the stop set screw which is fitted to some clutch pedals will be found screwed down too far. Slightly lifting the floor board by means of a rubber or fibre pad, or easing the set screw until the clutch is fully engaged, will cure the slipping.

NEW TRANSMISSION.

ENGINEER’S DESIGN.

What is likely to be the automobile of the future, at least in a number of particulars, was recently discuss,ed at Quebec, Canada, at the summer meeting- of the Society of Automobile Engineers. The various speakers talked about the details of development which promised motor-car improvement along Several lines. One of the addresses that attracted widespread interest was that of M. de Lavaud, a French ''engineer, who described his invention of a new transmission that eliminates gear-shiftling and automatically changes speeds. Fie said that the operation of automobiles on the streets of Paris with the new transmission had convinced him of its practicability. Because with ordinary gearshift cars the driver never operates continuously at the most efficient relation between speed of engine and wheels, M. le Lavaud claimed that the automatic transmission will increase the average speed possible and effect a fuel saving of more than 20 per cent in the dense traffic areas in cities. A long transmission shaft is driven directly from the engine and rotates an inclined “inertia, hub” which changes the rotation of the shaft into reciprocating motion. Connecting the inertia hub with the drive of the rear axle are rods which, by acting on roller ratchets, translate the back and forth thrusts into rotary motion applied by the brakes to the wheels. The trick of the transmission consists in the variation of the inclination or the inertia hub with the enginb torque and road resistance which automatically varies the throw of the connecting rods, consequently the rotation of .the wheels and the speed of the car. This automatic transmission is combined with a gearless differential and a planetary reverse gear located on the rear axle.

WHY STREAMLINE BEST.

NATURE KNOWS HER JOB.

“Because the pressure of the air from every angle must be considered, the designers of Segrave’s and Campbell’s machines had to depart from the rules established by airplane builders. It is the practice to test the air resistance of a very part of an airplane in a wind tunnel, and thus to discover the shape which can be driven through the air with the least amount of energy. Wind tunnel research proved that the traditional sharp prow of a ship is scientifically wrong. Fast swimming birds and fish are correctly designed. Nature discovered long ago that the prow must have a rounded rather blunt form, and that the tail must be fine if speed is to be attained with little effort. This is what is meant by ‘streamlining.’ No eddies must be stirred up, if possible, and no wake should be left behind. Foaming bow waves and wakes gladden the eye of the marine painter, but they are the visible evidence of inefficiency to tho engineers. The truth is that our locomotives and steamships pay too high a. price for speed in the form of engine power, and therefore fuel. Probably the Mauretania and the Twentieth Century Limited could attain their present, speeds with half the fuel that they now consume if they were streamlined.”