MOTORING WORLD

Manawatu Standard, Volume LIV, Issue 295, 10 November 1934, Page 9

MOTORING WORLD

NOTES. High hopes centre round a reported discovery of oil in Morocco. After long research, it is said that a considerable steady flow of crude oil lias been obtained.

The Monte Carlo Concours D’elegance used to be open to cars costing 100,000 francs ancl upwards. The luxury embodied in light cars lias brought about a change, and the,-, car costing half of this sum is now a beauty competitor. The historic car in which the Archduke Ferdinand was assassinated is exhibited in the war museum iu Vienna. Marks are clearly seen on the car. of the bullets that brought down upon Europe the Great War. The Ontario sections of the transCanada motor highway are to be completed this summer, according to the Provincial Minister for Lands and Forests. No fewer than 1000 miles of the new road are in the province of Ontario.

An interesting development of the last few years in British motoring circles lias been the spread of onemake car clubs, which are proving highly successful both from the point of view of members and the trade. By such means the members, that is to say, the car owners, are able to enjoy rallies and competitions, which give an added zest to their motoring, while the resultant interest in the cars concerned is all to the advantage of the manufacturer.

SQUEAKING SPRINGS

After they have been on the road for n time some cars develop squeaks in the springs. This is often due to water and dirt having found their way in between the blades. If rust has formed it should be removed by opening the leaves and injecting paraffin. The car should be jacked up at the chassis frame—not under the axle, since it is necessary to open the leaves —for then the springs, wheels and axle actually hang by their own weight from the frame, and the blades of the springs tend to separate. A screwdriver or special spring opening tool should be used to open the leaves- still farther. Looseness ol the spring clips may cause a squeak. Wear between shackle bolts and their bearings is another cause of spring rattle. Execessive sideplay between the shackle pins and the spring eyes will often result in noise. The latter trouble can be cured by tightening the nut on the shackle bolt. If this does not cure the noise, the cause is probably wear in the spring eyes and the shackle bolts. Care should be taken, when tightening the shackle bolt nut, to avoid excessive clamping, for this will restrict the free action of the spring and may result in the upper blades breaking. Shackle pins that have worn must be replaced with new oversized pins, the spring eyes being reamed out to fit. Regular greasing and spraying of the springs with penetrating oil will, however, help to avoid these troubles.

ELECTRICAL EQUIPMENT

There would seem to be no limit to the way in which electrical equipment can be extended, one component after another being added as time goes oil. For 1934 the most important addition was represented by the direction signal, which will, of course, generally be operated by a self-cancelling switch. Provision for an in-built radio set is an important 1935 development, which will lie found in very many cars. This will enable motorists to obtain radio equipment at a minimum cost, while its installation is facilitated by special provision for the components, aerials and suppressors. _ \ To cope with the steady increase in such equipment compensated voltage control was introduced on many cars of medium price for 1934, and will be extended for 1935 into the low-price field. In this system the battery receives a supply in accordance with the conditions, so that overcharging is avoided. Another 1935 development is to increase the dynamo output. Tandem windscreen wipers are to be general and many makers will employ the inverted type driven by a mechanism boused underneath the scuttle.

INGENIOUS FUEL TRAP

Under certain conditions of running, an appreciable amount of petrol is deposited in the intake manifold and may be drawn into the cylinders in a raw, anatomised form. To counteract that, an ingenious fitting has been patented. A tube is taken from the inlet pipe, near the carburettor, to a sealed container, so that petrol which collects in the induction pipe when the engine is cold runs back into the container. At the base of the latter is a circular pipe perforated with fine holes and leading, by means of another pipe to a manuallycontrolled valve on the intrument board. When the valve is open after the engine has warmed up, air is sucked through the perforated ring, and passing through the petrol which has accumulated in the container, feeds a subsidiary supply of mixture to the cylinders as long as there is any petrol in the container. The fitting is not put forward because of the slight benefit which might be secured from that source,, but principally as a means of reducing crankcase dilution.

ACCURACY OE SPEEDOMETER

INFLATION OF REAR TYRES

It is not generally realised by motorists that if the rear tyres of a car aro allowed to run with reduced air pressure, it might have a decided effect on tho accuracy of the speedometer. The gear ratio of the speedometer drive is chosen according to the back axle ratio and the tyre size. If the tyres are not inflated to normal pressure, their effective diameter will be reduced, since there will be more deflection of the tyro at the area of contact with the road. Therefore, for one revolution of the rear wheels, the car will travel forward a smaller distance than it should normally do, and accordingly the speedometer will show a higher speed than it should, or in other words it will read “fast.”

REAR-AXLE HUM. INACCURACIES IN DIFFERENTIAL. Both new and old cars sometimes develop a humming note in the rear axle, which is known popularly as “diff. hum.” Such a condition is evidence of some disturbance of the accurate meshing .of the pinion and crown wheel, and various adjustments aro provided for the correction of such errors. But the necessary work is definitely too delicate and intricate for the amateur, and should be carried out by a skilled mechanic and tested with proper gauges. A common mistake is to assume that the existence of “diff. hum” indicates that the crown-wheel and pinion are not closely enough engaged, and that the fault can be put right by manipulating the adjustment so that the pinion is moved into closer contact with the crown wheel. Often that is the correct course, but it is essential that the cause of the noise should be traced to its source before any variation is attempted. The humming might arise from wear of the beaimgs sup-

porting the parts, or from cliipperl teeth, and the wisest course is to have all the parts well examined and not to depend only on an alteration of the ineslung. Loss of good meshing can bo caused by any one of four defects; the crown-wheel may have moved,so as to tighten or slacken its mesh with the pinion, and the pinion may have shifted backwards or forwards with similar effects.

When rear axle noises give notice of some fault it is best to determine by a simple test on the road whether the hum occurs when the engine is driving the wheels or when the ear is coasting. The ear should be driven in top gear on a level road, in quiet surroundings. If the noise is evident when the engine is accelerated from a slow speed it can be assumed that the pinion and crownwheel are too deeply meshed, but if the hum is absent when the engine is driving the car, but begins only when the vehicle is allowed to coast in topgear, the inference is that the meshing is not deep enough.