MOTORDOM

Greymouth Evening Star, 1 May 1936, Page 4

MOTORDOM

NEWS OF THE ROAD

(By

“Gearbox” )

VALVE TIMING.

ADHERE TO STANDARD SETTING.

Many motorists are anxious to seek information on increasing the amount of overlap between the “inlet, opening” and “exhaust valve? closing” position. .. . Before passing to the question ot overlap it should be made cleai that the standard valve setting in all engines is a compromise between two extremes, and is the position which will provide the best all-round performance. If the valve setting is altered it will bring in its train certain disadvantages which will make the improved performance lose some of its fascination.

It is wrong to assume that the mere alteration of the inlet camshaft one tooth from its standard position will give an increased performance. The normal opening of the inlet valve on the majority of car engines is at top dead centre. Assuming for a moment that the inlet valve opening position is now put forward say 10 degrees after top dead centre, there will be a 10 degrees increase on the inlet closing lag position with a detrimental effect on the engine performance at low speeds for the following reason. In the cycle of operations performed by tho pistons and valves in relation to one another, the piston rises a very slight amount on the compression stroke before the inlet valve actually closes. To the uninitiated this may appear rather strange and probably give the impression that the rising piston would tend to push the incoming charge out again. This is correct if the closing position of the inlet valve is too late, but it is not so when the valve closing position is no more than 50 degrees after bottom dead centre.

The reason for allowing the piston to ascend on its compression stroke before closing the inlet valve, is that although the downward movement of the piston at the beginning of the induction stroke which created a gas movement, ceases at bottom dead centre, “vacuum” —to use a common term —still continues in' 1 the induction pipe, etc., and the gas will therefore continue to flow until its inertia ceases. This is the ideal position at which to close the inlet valve. It would seem, therefore, that if the closing positioh of the inlet valve is brought forward to 10 degrees after top dead centre previously mentioned, the closing position will be too late and the rising piston rapidly gathering speed will tend to blow the charge back through the induction system. Conversely, if the inlet valve is made to open before top dead centre, it closes earlier and a point well before the time when the incoming charge has reached its maximum speed, so that in this position the cylinder does not receive a full charge and consequently a power loss is sustained.

The object, therefore, of setting the camshaft in advance of the standard position is defeated by virtue of the design of the cam, and if improved performance is desired, a new camshaft with teams ground to give the necessary longer opening period and approximately the same closing position must be used.

With the fitting of the correct type of cams, additional miles per hour will certainly be obtained, but “what ife sauce for the goose is also sauce lor the gander,” and if the engine is improved in this direction it must also be improved in other ways, if mechanical break-downs are to be avoided.

Additional miles per hour will be obtained as a result of the increased revolutions per minute, but at the expense of imposing additional stresses and strains on other parts of the engine. Car manufacturers consider it inadvisable to alter the valve timing except on special engines, as the alteration entails the loss of slowrunning and involves increased petrol consumption at low speeds as well as making the engine extremely rough. The owner is therefore well advised to leave questions of variation in valve timing to the racing enthusiast and adhere to the standard setting.

NEW' CHRYSLER AIRSTREAM. A recent test on New Zealand roads revealed the distinctive charm and performance of the 1936 Chrysler Airstream. It was obvious at the first glance that the new car is a sleek, trim, beautiful creation. The flowing line has been notably beautified, giving long, low, finely tapered lines and smoothly rounded curves that express modern style with high individuality. While built on the same length chassis as the 1935 model, the 1936 Chrysler Airstream actually has the appearance of being many inches longer. Through a unique rearrangement and redesigning of the interior, three inches more width in the rear seat and also in the front compartment have been accomplished. Within the body itself, there is an increase of four and one-half inches of passenger space. This has been made possible by moving the dash forward and by redesigning the rear panel. Additional leg room is also provided. Several important improvements in the ventilating system permit a scientific circulation of fresh air to suit individual passengers and to prevent draughts.

The radiator is a flashing shield of stainless steel and enamel, beautifully designed to carry out the greater streamlined appearance of this 1936 Chrysler Airstream. The body of the car, solidly built of steel and welded into one unit, is fastened directly to a frame of exceptional strength, so that the two serve to strengthen one another. The combination of new frame design and direct body mounting lowers the whole body one inch, adding greatly to stability and roadability. An important improvement in the new car consists of rubber pads which completely insulate the body from the frame.. At no point whatever are the frame and body in actual contact—thus road noises cannot be transmitted through the frame of the j body. There is no rumble inside the ■ body, due to this effective insulation. | The test revealed other surprising, Chrysler features, too many to be re- ’ ported in this short description. Suflice it to say that the new car is full of delightful improvements, making it an outstanding achievement of modern engineering and science.

STOP! LOOK! LISTEN!

MOTOR CARS AND A WARNING.

(The Author (Rupert H. Tribe) acknowledges inspiration for this article, published in the “Sydney Morning Herald,” to one published in the “Readers’ Digest” in August last year, entitled . . . “and Sudden Death, by J. C. Furnas, an American journalist at present travelling in Australia. In the article herewith the Author has endeavoured to drive home the gruesome reality of the figures relating to motor accidents, to. analyse the chief causes, and to pungently re-state the rules for "Safety First and Always!”) There is no form of death and injury worse to look at or take pait in than a bad motor accident. 1 have been driving motor cars for 33 years without being personally responsible for an accident, or in one, or the pedestrian victim of one. I have not smashed a car up or been in a smashed up car, for reasons which I shall presently set forth. I have not been the pedestrian victim of one because I am prepared to never hurry, forget my business and pleasure, concentrate on my safety, and pray for a large measure of luck whenever leaving the safety of the footpath anywhere. Wowen are vastly safer drivers than men. They have a quicker imagination, no special pride in the mechanical performance of their car, little desire to see or accept a speed challenge, and they place a much greater value on their own and others’ safety both in the abstract and the concrete. When a woman driver has an accident it is genuinely an accident. When a man driver has an accident it is often the result of reckless folly, overweening egotism, or sheer damn-fool lack of common caution .. . plus speed. Approximately four hundred people were killed and eight thousand injured by or in the automobile last year in New South Wales. How many men, as they read this, will . . . Stop! look! and listen? Very few! But thousands of women will; their quick and colourful imagination, plus intuitive practical common sense, will visualise a veritable battlefield of' dead and maimed. Then, as is a woman’s way, it will become instantly personal. They will shudder and glance fearfully at their loved ones; their darlings of school age . . . the grown son or daughter, perhaps using a jolly speedster or sports car . . . the beloved husband, who perhaps has a couple of “quick ones,” then races home, “Wouldn’t keep wifey waiting for anything!” except sudden death. Women who drive cars don’t drink when driving .. . many men do. Women don’t “shout” and it’s easy to say “no.” Men “shou,t” and can’t get out of it.

Somebody has said that life is a paradox of which the only solution is death. Well, here is another seeming paradox: women are the “safe” drivers . . . men are the “best” drivers and the “-worst.”

CASUALTIES. You know that old familiar column in the newspapers . . . doesn’t mean a thing to you personally . . . just a few paragraphs. Somebody’s little boy or girl; father or mother; son or daughter; ambulance .. . hospital . . . morgue! Even a call at the hospital or morgue will only temporarily make you realise that “stepping on it.” is giving death a “lift” and a chance to do another gory job. But if you could have been on the spot and seen those accidents at the moment they happened!; The elderly grey-haired woman .. . somebody’s mother .. . leaves the pavement; a tew hurried steps ... a split-second sense of danger . . . crouches paralysed with death in her eyes ... a scream of tyres, and a dull crash . . . blood and mud and horror! Perhaps a little child . . . pathetically crumpled ... a look of arrested unendurable agony on tiny twisted face. Speed and more speed; powerful cars and perfect road surfaces; speed and reckless blind egotism, inherent atavism and drink —and you have the mixture that composes 90 per cent, of the motor accidents recorded with cold regularity in the Press. The undertakers’ best friend and' the hospitals’ main work and debit.

Here .is another shuddering penpicture of what it means when an automobile —perhaps yours—is driven with death at the wheel. And this time you are going to a massacre. It’s a perfect Sydney day, sun shining from azure skies, perfect visibility, soft warm breeze. We’re off to Katoomba, the whole car load of us, three Jacks and three Jills (Jack fell down and broke his crown and Jill came tumbling after—well, it’s a hill this time but not a pail of water). “Step on it, Jack!” “Don't be a goat—let’s gpt past Homebush —we’re doing 50 now!” Gee! Jack, she’s a humdinger! (just 120 b.h.p. of tons velocity to th square foot). “Say folks, just a small gargle at the Woolpack—sez you!” And now “we’re on our way to Mandalay .. .” “Say, Jill, when 1 say ‘Prospect’ I mean ‘damn’—a big one, get me? Fla! Ha! “Count ’em up Jill—that's twenty-four eating our dust since Paramatta! “Get this one, Jack—step on it—it’s a ‘go’ boys—there’s nothing coming over the top—it’s all over bar —Crash! Crash! Crash! Just three cars in one ghastly mess. Two racing neck to neck, and one coming the other way, as thej- reached the top of the hill—together! “Every action has an equal and opposite reaction!” That’s a law of dynamics. So, when your car is doing ‘fifty’ and stops deadi—very dead and suddenly—your body just continues to travel at ‘fifty’—as far as the roof or tlie windscreen. If another car has rammed you amidships or telescoped it head-on, your short flight is complicated. With a third car for good measure —well, flesh and blood and bone just can’t stand it. Torn, ripped, spouting, broken, scalped and pulped. Clawing, moaning, gasping, shrieking, and lying very still. Impaled and crushed. Jack and Jill went up the hill—witfy speed and liquor and bad judgment—that’s all; blood and agony and sudden death.

THE SPEED CRAZE. / There's just one major cause of motor accidents—speed! To-day most cars have an overplus of power. And to-day most male drivers use a lot of it all the time and all of it some of the time. And 75 per cent, of drivers.

have not the necessary temperament •to be in charge of a hurtling deathdealing machine such as the modern car.

There's just one way to drive a car properly and safely and continuously under present conditions. That is to be prepared for every contingency all the time and everywhere. And that is not possible at speed. The “safe” driver must rigidly (one hundred per cent.) observe all the rules of the road. He must assume that no one else will—and be prepared, therefore, for the other fellows’ negligence, or ignorance. He must believe that every child and old party is going to step suddenly into the roadway, and that every cyclist and dog is going to get under his radiator —and give them ample yet not startling evidence of his approach. He must believe that every other vehicle is going to stop cr turn suddenly, and without warning in front of him—because they will certainly do it—sometime. He must

reckon that a mad mullah is going to career blindly or drunkenly out of every side street. He must never overtake on a rise or on a narrowing or curving roadway. He should never drive ‘blind’ at speed into the other hog’s glaring ill-focussed headlights. He should always remember that you can’t see khaki at night, or too well at any time —that’s why it’s army shade. He should always make sure that his brakes are effective — all the time and all of them —not afterwards. He should never guess about anything—or make a psychic bid; that’s alright at “contract” sometimes.

And above all else, if a driyer is once convicted of driving while under the influence of strong drink, he should never again be permitted to hold a license; might as well let him loose with a machine-gun. And though, as I said earlier, the fair sex are instinctively “safe” car drivers, nevertheless, these rules for

driving safely are worth their close consideration also. I might add finally that I never get into a car unless I know the driver is “safe’’; what’s a picnic or a “lift” if —well, I don’t repeat it?