MOTORS&MOTORING

Dominion, Volume 9, Issue 2798, 16 June 1916, Page 9

MOTORS&MOTORING

[By Clutch.] Increasing the Car's Power. The power of a car can be increased in several ways, and the method ohoson must depend upon Hie results desired and ■ the expenditure one is willing to innke on improvements. If an increased ability to climb hills, or negotiate heavy sand, is all that. is required tho difficulty can be solved by using a lower gear ratio. • Of coursc, if this is dont iho engine will run faster for a given speed of the car, and, in general, the machine will not be capable of quite as high speed as before the change. Such changes in gear ratio, however, have made many cars do good work in a district where they were at first condemned as not powerful enough to negotiate hills or sand. In cases where the power of the engine is to be increased, and lienco both tho speed and hill-climbing ability of the car to bo improved, tho problem not nearly so simple, and the question of cost is often the deciding factor. There are three general ways of increasing tho power of an automobile engine, and they are: (1) Cut down friction losses and inertia losses, due to reciprocating moving parts. (2) Increase the speed at which the engine may be economically run. (3) Enlarge the valves and gas passages and thus allow more gas to l)t> taken into the cylinders, and hence more power produced at a given engine-speed. These have been taken up in the order of the difficulty which generally attends their accomplishment, and it should bu added that the last two are so intimately related that they are generally done together. The method of carrying out the abovementioned improvements must, of course, vary with the particular motor in question. Inertia losses may be materially reduced.by the use of aluminium alloy pistons, and the use of such. piston 3 will .also'out down the friction losses in the cylinders. Where more money is available it is sometimes possible to still furthe reduce the inertia losses by putting in lighter connecting roda made ol u high-grade alloy steel, but such a "hango should not bo made without consulting a competent engineer as to the strength of the proposed new parts. In ail cases where undue friction losses are suspected the lubrication of the bearing, or bearings, in question should be improved. f An almost, unlimited amount of money can. be spent (and sometimes wasted) on the two latter kinds of improvements, and in most oases a new motor will be the most practical solution of tho problem, but if the power of the old motor has to be increased it can be dont in the following way:—First, light pistons and connecting rods should be installed; secondly, tho valve timing should be altered to suit tho proposed increase m speed; and lastly, the area of ttio gas pasages should be enlarged, the valve seats bored out, and larger valves :n----stall- and a larger carburettor fitted to the motor. The great' difficulty of making these changes lies in the trouble and expense involved in increasing the valve sizes. At the best it is a big ■job, but it can be done, and where a etock car is to be converted' into a speedster or racer it may prove worth while. One successful English racingengine was made from the Btock; motor or the L-head type by boring ont'the cylinder heads and putting a single big inlet valve'in a cage in. the openin? this made in. each cylinder' head. Thesi, overhead inlets were driven by rockers and long push-rods from the cam shaft in the base; both the ordinary valves located in the pocket at the side of the cylinder were used as exhausts. Cushioned Wheels. The problem of securing resiliency, in commercial.-motor vehicles without departing from a durable form of tire has Jong engaged ihe attention of inventors, borne cushion tires of ingenious design have lately made their. appearance, but the solid rubber tire is found to be the most- enduring and -practical so far as commercial vehicles are concerned. Approaching the problem in another way than by altering tho tire, some producers are turning out cushioned wheels. One type has a double hub formation, in which cylindrical blocks of rubber are placed in semi-circular bed 6paoes between inside and outer hubs, these acting :as driving members as well as cushion--ing elements. As the rubber is not subject to depreciation due to contact with the road, as the outer solid tire is,'it ,can bo of very resilient composition. Another cushioned wheel acts on the same principle, except that the cushioning ele. ment is carried out near the rim.' The solid tire-is oarried on the outer rim, -which rests upon the special soft rubber cushion interposed between it and the wheel felloe.

Engine Efficiency. In order .that the efficiency of an engine may be maintained at its maximum it is important that the requisite amount of compression. for which. the engine was designed s.hould be maintained; for though it is true that energy cannot be added to that already stored up in the explosive mixture, the act of compression ensures that the maximum energy is utilised. It might be argued that to further increase the compression would serve to render the energy more effective, but there is a limit of compression which is soon reached, and the mixture, would bccome self-igniting. Even if this point be not reached, the'mixture would fire so rapidly as_ practically, to cause a detonating explosion, and would result in a very harsh running and uncontrollable engine, quite unsuited for touring purposes. Here and There. In 1770, a Frenchman, Joseph Cugnot,' built a steam automobile which hauled three tons a distance of three'miles. This' automobile is still in existence in France. A writer in "The Motor" 6ays: "There is a proper throttle opening,for every bill under given conditions. It i 9 such nn'opening as will take you up with the engine turning just happily. More than that or loss than that means strain. I cannot give you any rule or formula; you must just feel for the opening; cultivate a sense of sympathy .with your engine; float up the hill. /There is "no. sense in getting lip at 40 miles an hour. Wear and tear increase out of proportion to speed in hill-climbiae. You will strain your engine on a hill probably four times as much at 30 miles as at 20. Do not overwork the willing 20 h.p. This bill-rushing propensity is the novice's, mistake. He sees a hill ahead, doubts whether he will get up it, .opens his throttle wide, and howls up, patting himself on the. back for his folly. . .'. Next time you approach one of your pet climbs try a two-thirds throtle, awl the next timn after that you will probably be content with one-half." An American inventor has patented a < device whereby, the rear light is inter, connected with the gear level, so that when the gear is put into Teverse a white light is substituted .for the red glow in the tail lamp, thus giving a good light ior backing the machine and warning following traffic. , Soap is useful to the motorist in more ways than for clcansiug purposes.' A wayside repair of a petrol leak may be deiilt with satisfactorily with a bit of yellow soap made sufficiently plastic to m?,nipulate it. After pressing.into thq defective joint a wrapping or two should be placed round the "repair." Petrol .will get through most of tho substances, usually employed for 'this temporary service, such as white lead, rubber solution, etc., but it has only a very slow action on soap. A wind screen may bo kept free of raindrops if a piece of clean rug is moistened and rubbed on_ the soap and the glass :then covered with a' film and allowed to :dry and lightly polished afterwards. Still another use for soap is a. makeshift lubricant for gear wheels, springs, and parts : where there is heavy pressure between the surfaces. . Lighting-up time: To-day, 4.26 p.m. Next Friday, 4.27 p.m.