THE MOTOR WORLD

Otago Daily Times, Issue 19010, 5 November 1923, Page 5

THE MOTOR WORLD

By ACCELERATOR

WHAT’S YOUR HURRY ? What’s your hurry ? Wo live in an Age of Speed, it is true, but it we expect to live in it long we must set a cautious pace. ENGINE KNOCKS AND PINKING. HOW TO TELL THE DIFFERENCE BETWEEN ONE AND THE OTHER. If your engine is knocking, can you tell whether it is really knocking,' pinking, or detonating? (asks Captain E. de Normanville in the Daily Chronicle). All these three are generally looked upon as being the same. But they are quite different. And, as their importance differs consicierably, it is as well that you should know, ‘t’other from which,’ and how to find out what ails your engine. And it is a comparatively simple matter. A- genuine “knock” is a matter which should have your early attention if you do not wish to lie stranded and incur extra repair bills. There is a distinct difference in the sound effect of a knock by comparison with pinking or detonation. But many motorists find it difficult to tell one from the other If you have an unpleasant sound from your engine of the knocking or pinking variety, you should immediately see that you stop it. If retarding the spark eliminates the noise entirely, it is only pinking—and not serious. But if when you retard the spark you still have a dull and subdued ‘ thud emanating from the engine, it is time to fear the possibility of a genuine “knock. Such a knock will bo due to a worn bearing, either the “big end” or the gudgeon pin bush -the latter is sometimes called the “little end.” To make sure, you must become your engine’s dor-tor ! You know how a doctor sounds a patient’s chest with a stethescopo? You con sound your engine’s chest in just the same way. You want a piece of hard wood, about a foot or two in length and about half an inch in diameter. One of the old-type circular wood rulers is excellent for the purpose. . , The feared “thumping” of your engine s heart is either in the big end or little end of the connecting rod. Put one end of the stethoscope on the outside of the front or rear bearing of the crank-shaft casing, as may be the easier. With the engine running slowly, place the lobe of your ear on the other end of the stethoscope, and press your ear against it with sufficient pressure to close the ear to any sound other than that coming up the piece of wood. You will now find your ‘ thud takes on a more definite sound. Transfer the itothescope to the outside of the cylinder walls, taking- each cylinder in turn. The cylinder which is at fault will give a pronouncedly louder knock in the stethoscope than the other cylinders. If you heard a similarly loud knock on the crank-shaft end bearings as well, you will know that it is a big end that is worn. If the sound is louder on the outside of the cylinder wall, it will be the little end which is at fault. Either should be seen to before it gets worse, but instead of saying to your repairer, “There’a something .wrong with the engine,” you can say, “I want you to take the bottom half down, and just tighten up No. 3 big end.” It's a much cheaper job when you give instructions like that! Momentary pre-ignition pinking (or, as it is so often erroneously called, “knocking”) dpes no real damage-;so long as it is only momentary. But if the spark is not quickly retarded you tend to produce worse ills. Pre-ignition generally comes in this way. As your engine gets carbonised you reduce the available compression area, thus tending to cause automatic ignition, and particles of the carbon stand up pinnacle-wise and become incandescent. This incandescent spot may fire the charge before the “official spark” actually sparks. And that firing takes place too early on the upward travel of the piston. If your engine is clean and still shows an inclination to pre-ignite, the sparking plug is the nrobable cause. Change it for one of accepted make with a tliicker central electrode. Pinking and detonation troubles can always be cured or greatly reduced by using some benzole or benzole mixture with your petrob A VISITOR’S IMPRESSIONS. “Chassis” (of Christchurch Sun) recently spent a holiday in Dunedin and has published his impressions:— in the matter of population, traffic, and traffic control there is very little comparison between Dunedin and Christchurch. Not that the authorities in Christchurch have anything to boast about in traffic control, both vehicular and pedestrian. On the other hand, there is a certain laxity in this city which does not augur well for the future when the traffic is still further increased. This laxity has been a thing of slow growth, suitably encouraged by the City Councils of the past. Traffic hag been allowed to do much as it pleased, and pedestrians have never received serious attention. It is well to tackle the problems of traffic as that traffic is growing, and now it seems to me is Dunedin’s chance to render orderly the slight confusion of the present which promises to become a chaos of the future. That traffic congestion apparent in Dunedin at present will become greater as time passes, even more so than it will in Christchurch, where there are so mauv main streets.’ Dunedin has but one that is popular, and that is Princes street. This muchused thoroughfare has been much improved since the central tramway poles were removed, but it seems that at the intersection of High and Pnncos streets there will always he trouble with trams, oars, and pedestrians crossing and re-crossing. I noticed a traffic policeman on duty at this point, and understood that his appointment was in the nature of an experiment. If so, or otherwise, his influence did not seem to count for much. When he was not talking to a pedestrian he was -iving signals that wore very distantly related to any system. It would bo wise to appoint a man who knows the work thoroughly, so that the public may be educated. Motorists in Dunedin, almost without ex-

ception, slick hard to the rule, compelling them not to pass halting or halted trams. The drivers travel at a reasonably fair speed, and carefully. I noticed one motorist attempt to cut a corner on his wrong side. Three constables were chatting in the roadway. One drew the driver’s attention to his breach of the rules of the road, but nothing further was done. Motorists must be educated, and it appears that a fine or two helps in that education. But motorists in Dunedin do not sound the horn at corners. Even motoring councillors in Christchurch forget that paramount duty. The Otago Motor Club is a live organisation without an established home. It is regrettable that there should be so much opposition to the proposal to secure permanent headquarters, but when the membership grows, as it shows every promise of doing, the dissentients will no doubt change their minds. It occurred to me that members could assist in a membership campaign by canvass instead of relying on lean etc 'Hie personal touch wins every time. For instance, hundreds of now members wore obtained in Canterbury last year through the efforts of members of the Canterbury •Automobile Association. Publicity is .a great, force, and it seems that the best publicity method —the newspapers—is not fully availed of. Fords seem to predominate in Dunedin. “KNOW ANT TARNS?” All’s Eni Moots’ brother wuz so used t’ facin’ fast trains in th’ movie theatres that ho neglected I’ slow down at Tharp’s Crossin’ yisterday. He wuz assembled by Coroner Gabo Crow. “Can you tell me how far it is to Little Mucklestone ?” asked the motorist of the farm hand. “Aye, zur; about a stone’s throw, as the crow flies, if ye drives fast!” “Do you think the motor will entirely supersede the horse?” ’T hope not.” replied Farmer Corntossel "There must be some market for hay. I depend on what 1 make on hay to buy gasoline.' 1 “I hope some day,” remarked Mr Chuggins, “to give up my flivver and have a private yacht.” "Why do you prefer the yacht?” “I can go to bed without being disturbed by the fear that someone is going to steal it out of the garage.” A Blenheim wag has originated a new car story. The other day a well-known Blenheim owner was performing prodigious feats with the starting handle, without the slightest response from the sulky engine, when the wag happened along. He watched the winding process for a minute or two and then drawled: ‘Say, why don’t you get an eight-day one?” “Are you still dreaming of owning a little home in the country’?” “No,” said Mr Gadder. “We invested the money wo’d saved up in a motor car. Now wo can go out on a Sunday afternoon and raise such a dust that the people who own little homes in the country wish they were back ii} town.”