MOTOR NOTES

Opotiki News, Volume I, Issue 59, 20 July 1938, Page 4

MOTOR NOTES

IF THROTTLE JAMS . . Although *a rare occurrence, the jamming of the throttle pedal in the ••open position >s not- impossible. > ix tlie throttle pedal jams, the driver should switch the engine off iui- ' mediately and apply, the brake., in the normal, manner. It lias been stated that die car will i 4 bo held in control by declutching, but / wjiilo, this is true, the -engine, relieved of its load, will imnfediately neoel: crate’to its maximum possible speed, and the noise it. wakes may distract the driver’s attention for the moment from the job in hand, which is to sfcuo the car. In addition, if the engine is allowed to race like this for more than a few seconds, there is a distinct f possibility of a connecting rod breaking. Wherever possible, it is always better to switch off before throwing out the clutch. . ’ ROAD ACCIDENTS !N U.SsA. _ * " * The Automobile Safety Foundation of America has advised that there are now many encouraging factors in the outlook for highway safety in the United States.

It is stated that highway fatalities throughout America showed reductions of 10 per cent, in both November and December and 17 per cent, in Janu-

ary, with indications of substantial reductions in February, when final totals are compiled for that month. These reductions were made in the face of increases in car use, as indicated'by motor fuel consumption.

The present death rate of 15.9 per 100, OX',COO vehicle miles is the lowest ever recorded. in America, •and: indicates an improvement of 14 per cent, over th'e year 1934, which showed the highest rate as related to “exposure’’ or motor car use.

THE DIFFERENTIAL WAS PATENTED FN 1827 . That ingeniously* supple piece of mechanism, the differential gear, which allows the inside back wheel to slow in >relation to the outside,one when negotiating a corner, and without which the 'moton- ear would not be the safe, efficient vehicle it is, had its origin early last century. it is thus one of those standard features of car design which was invented long before the internal combustion engine appeared. Towards the end of the eighteenth century and during, tlie early part of the nineteenth, engineers were very busy experimenting* with steam-propelled road vehicles, and a good deal of progress was made, some of these vehicles proving capable of quite a good turn ol’ speed. One of the big problems was the unwieldiness of a vehicle, with huge, steel-tyred wheels, when negotiating a corner. This was

due to both driving wheels being connected by a soljd axle.' One method of overcoming-,the trouble was tb : use a single, central driving , wheel’,- find, another to drive a wheel bn one side only, leaving the other free .tojf-ro-volve on the axle. Neither of these >vds entirely satisfactory, and vain, b attempts were made for years to. hud a solution to the'difficulty.- ■ Used' on Cteam Road Vehicle • in 1827 a Frenchman, • Onesiplioro Fccqueur, filed patent specifications for a differential gear whose principle is exactly that of the gear used today, and it was used successfully in a steam road vehicle which Facqueur built.

A few years, later, an English engineer, Richard Roberts, invented a precisely similar gear, apparently being unaware of the French inventor's earlier patent.’ ' *

Thus, many years before v the motor car appeared, the differential gear was in fairly general use. Without it. the stability and! efficiency of the modern car would not he pcssiljle,

Another interesting fact in connection with those early steam-prb]|elled vehicles is that one was produced! with three forward gears, by meafis of three sets of chains and sprockets of different size, the set required being engaged by dog clutches and the other running free. This is. exactly the system used in a fairly well-known light English sporting car to-day.

NEW BRAKE SHOES For years brake linings have boon riveted to brake slices,: with, the rivets countersunk about half-way down so that the linings have to be thrown away when about half ,worn in order to prevent the rivets coining int t contact jvitii the drums. An English manufacturer has invented a rivetless lining which' is so designed that practically the whole of the fabric can be worn away before replacements are necessary. - Tlie fabric is woven on to a slotted steel, strip, the whole being compressed under heat to. form a unit, Helming the shoo . simply involves the attachment of the strip to the shoe by four small bolts. Apart from any other considerations brake relining ' becomes greatly simplified by this new scheme, .and, as it has been introduced by a brake manufacturer of some importance in the motoring u&rld, it is possible that it will shorn become a standard fitting on several well-known makes of car. LITTLE KNOWN FACT With reference to the articles which have appeared from time to time concerning the importance of cleaning and setting'the points of the ignition distributor at fairly frequent intervals, it is not generally realised that a wide gap has the effect of advancing the ignition. This is a further argument in favour of the careful adjustment of these

points after they have been cleaned. The correct gap in most cases is .013 in., but the ■’proper setting can be obtained from tlie manufacturer's instruction book.

In setting this gap, almost invariably it will be found that an engine stops with the rocker arm off the cam, so that the points are closed. To save the trouble of getting out the starting handle, in order to get the points open, try the effect of moving the distributor head to retard position. This often will open the points fully, but if it does not, then touching the starter button to slightly alter the position of the cam, and then swinging the distributor head, should attain the desired object.