LATEST IN CARS

Timaru Herald, Volume CXXV, Issue 18459, 28 December 1929, Page 14

LATEST IN CARS

SILENT THIRD GEARS COMING OF THE SPRAG. One of the outsanding features of the Olympia Show is the large number of cars fitted with four-speed gear boxes, and the increase over -last year of the use of coil ignition, which—it is stated—is now used on 60 per cent, of the makes of cars on the British market. Till recently American designers regarded four speeds as unnecessary on cars of high horse-power, but there are no less than five American makers among the converts to the four-speed gear box. The increased popularity of coil ignition is due to the fact that modern coil apparatus is efficient and entirely reliable. It is also a means of slightly reducing the cost of the car, though this is of small importance compared with reliability. For many years coil ignition suffered from a prejudice against it handed down from the very early days of motoring, when coil, condensers, contact breakers, and distributors suffered from as many defects as did the early chassis themselves, and batteries gave endless trouble, as they were not specially built for the work they were called upon to do. The battery has been so greatly improved since those days, both as regards mechanical construction and electrical efficiency, that there is now no reason why an ignit.on system depending upon it should be suspect. The American conversion to the four-speed gear box is not a conversion to four forward indirect speeds, but the adoption of what is known as the “silent third.” This is obtained by various applications of the use of constant mesh gears, some makers using external and other internal forms. It is the perfection of these systems that is making them popular. They are often spoken of as “twin high.” the use of the term arising from the fact that the driver has the choice of a speed of slightly lower ratio which he can utilise on hills or in traffic without the car giving any indication of being on, an indirect drive. One of the American cars, in addition to its four speeds, also has a sprag to prevent backward running on hills. The sprag also enables the car to be started on a hill without the driver being troubled to hold it on the brakes, an easy and clean get-away.