Motoring

Hawke's Bay Tribune, Volume XV, Issue 167, 20 June 1925, Page 14

Motoring

SWEET RUNNING.

AND THE CUMi’RESiSION. -POINTS WHICH COUNT. A joke that is often played upon the ran garage apprentice is to send him out to buy a 'can oi compression.” And since the coming ot the seifstarter, engine compression might as well be in a can lor all the average motor-car owner knows or cares. I>ul, probably, the chief secret oi a sweetrunning engine is—compression. Try the compression 01 each cylinder by tunning the engine over with the hand crank. If it is weak m- if it varies in different cylinders have the trouble repaired at once. Compression may leak past the piston rings; it may escape through a leaky valve, or ooze past a sjxirk plug. 'I here possibly may be a cracked cylinder, in which case you are totally “out of luck.” A couple o' piston rings may have turned so that both grips are in line or you may be using such a light oil that the engine does get a tight compression seal. Some oils when heated are very thin, in some cases patented piston rings will help eliminate the leakage. If the cylinder is worn oval there is no remedy, except that of reboring or replacing it. Kerosene will help tree the rings of carbon, but it is best to use it when you are ready to drain off the old crank-case oil. .Make sure that the spark plugs fit tightly and that, they are provided with good asbestoes gaskets. A cracked porcelain will allow compression to escape. Look over the priming cups and see that they all fit tightly and stay closed. During compression the valves should be tightly closed. A broken spring or faulty adjustment will prevent their closing, and this will result in no compression at all, or, in the case of incorrect timing the trouble will be noticeable as a lack of power in all cylinders. Carbon under the values will prevent them from seating tightly. The remedy here is to keep the engine free from carbon, the valves clean, and Ik* sure that the timing of the valves and the tappet, adjustment are as set down in your instruct ion book. When an engine that is clean, properly lubricated and has its valves ground regularly, shows a, serious loss o!< power, the lack of proper compression may safely be ascribed to some of the piston ring gaps having worked into line or the cylinders having worn to a point, whore the pistons are unduly loose. With the modern type rings, the former is a .rare fault nowadays, so that the cause is narrowed down to plain wear. These are the chief causes of loss of compression. Watch the compression —it will save you money that- otherwise you would give to the repair man. * * * * SAFE DRIVING SPEED. I LX El) BY STOPPING DISTANCE. 'The suggestion put forward in France that, motor traffic should Ik* regulated not by speed limits but by the ability ot motor vehicles to pull up in a specifiexd number of feet, according to the locality, has attracted considerable attention in America. The “Scientific American” (New York) in an article dealing with the subject, states:— So long as it is the inability to stop in lime which is the cause of most accidents and the reason for all speed laws, let us go directly to the source of the trouble. Let us require that every car shall he driven only at such a rate that it may be brought .to a complete standstill within specified distances; these distances varying with country and ci.ty driving conditions much as do the variable speed rates now permitted. Wo could stipulate, lor example, two hundred feet as the required stopping distance on an open country road, fifty feet in some sections of the city, even fit teen or twenty feet in the more congested portions. We could mark all school streets as “ten foot zones” indicating that, on such streets the motorist must have his car under such control at all times that it can be brought to an absolute stop within ton feet after the danger has been noted or after a proscribed signal has been given. One of the principal values of such a system is that it would take into consideration. absolutely ami automatic-

ally, all conditions then prevailing which would affect the stopping ability of the car or of the driver in question. On a slippery road the driver would need to exercise much greater care and would dare drive, possibly, at only a quarter of the speed that would permit stopping within the same distance on good, dry roads. The design and condition of the braking mechanism would represent, also, a vital factor in determining the speed at which the car might, be operated without danger of violating tho stop-ping-distance provision. The operating machinery for such a method of speed regulation would be much simpler and more effective than that employed a.t present. Quibbling over the inspection and accuracy of speedometers and disputes as to Ijie distance over which the speed limit had been exceeded would be avoided. All that might bo necessary for proof of careless driving would be a .taj>c line and possibly a piece of chalk. No expensive motor-cycles or high-speed cars arc needed, nor any highly trained body of “motor-cycle cops.” Every policeman could produce the necessary evidence of careless driving.

Suppose, for example, that a police officer on foot is walking on what is known as a “twenty-foot street”—this meaning that any vehicle driven on that street must be operated at such a speed that it can be brought to n dead stop within .twenty feet. The pavement is wot. The jioliceinan. seen a car approaching at what ho considers ! to be a dangerous speed. He need only step to the curb, raise his hand and blow his whistle. If the motorist is able to bring his ear to a complete stop within twentv feet from the point at which the prescribed signal was given. he has demonstrated that he was driving carefully, within .the meaning of the law. It is inconsequential whether his speed was ten or twenty miles an hour, whether he used chains or non-skid tyros or whether his car was provided with two or four-wheel brakc< Those matters are entirely Ins own business. He has passed the test. “As long as we have automobiles, we will have the eternal discussion of what constitutes a safe driving speed. Then* is but little room for argument, however as to what constitutes a safe stopping distance. This stopping distance represents the entire basis on which safety depends. Why not adopt the plan of using this stopping distance, not a speed limit, as the sole method of judging the carelessness of car operation?” « * * * TIME-PAYMENT SYSTEM. It is interesting to note the growing popularity ol the Chevrolet car in U.S.A. In March this vear the output was over 48,000. In the same month 173,000 Fords were turned out. It is now an easy matter to buy a Ford in America. The latest Ford purchase plan in Detroit (I .S.A.) is as follows: A deposit of £2 10/- secures delivery of car, the balance being paid by weekly instalments o!< £l. By the introduction of this easy purchase system Henry Ford expects to open up a new big virgin field for sales in U.S.A. BRITISH CAR PRODUCTION. British car production has made a notable advance during the past two years and it now hxiks as if the British car is again coming into its own again. In 1922 the value of British cars made was £20,000,000 and despite greatly reduced prices m 1921 the figures totalled £36,000,000. In 1922 cars made numbered 40,000, as against this in 1923. the output was; Private cars (17,334, commercial vehicles 22.34(5, whilst the 1921 totals were 102,248 cars, and 31.350 commercial vehicles. * * # * SHORTAGE OF RUBBER. It is stated that unless provision is made to increase the world’s output of rubber, that by 1930 there will not bo sufficient crude rubber available to cope with the world demand for motor tyres. In America in 1911 only 3300 tons of crude rubber were used for motor tyres. In 1923 the motor trade in that country consumed 251.000 tons or S 3 per cent, of the rubber imported into U.S.A. By 1930 it is predicted America will require 400,000 tons for motor tyre manufacturing alone. The world’s output of crude rubber for 1925 will he in the region of 481,000 tons.