MOTORING WORLD

Manawatu Standard, Volume LVII, Issue 212, 7 August 1937, Page 7

MOTORING WORLD

NOTES. The problem of polishing the contact segments of a distributor cap without scratching or damaging them or .the insulation is met by the use of an ink eraser. The use of sand or emery paper should be avoided in distributors where a carbon brush is used to establish contact, but the eraser is safe. A simple way of ascertaining the working conditions of an engine is to take out the spark plugs and examine the firing points. With correct combustion the points should be grey-black, without any signs of soot. Too rich a mixture gives them a black and sooty appearance, while a weak mixture leaves the points white and parched. Wet oil on the points usually indicates worn piston rings and cylinder walls; this also applies if the plugs carbon up frequently. The correct operating temperature of an engine is from 160 to 180 degrees, and if the various adjustments are in order the heat gauge will normally rest at about that mark. Although it is more usual for overheating to take place, there are occasional cases of overcooling. Short runs and cold weather bring it about, and the remedy is to remove the fan belt, or blades, or arrange a partial shield to cover the radiator core. When having plugs tested in a mechanical testing machine, it is necessary to have them clean first and the gaps readjusted before actually carrying out the job. This will then show whether the plugs are fit for further use. HEADLAMP ADJUSTMENT. Motorists should pay more attention to the adjustment and focussing of the headla.mps on their ears. Far too often a car is passed with one headlamp cocked at such an angle that it throws its beam directly into the eyes of approaching drivers, blinding them temporarily and adding greatly to the dangers of night driving. The problem of dazzle is bad enough with headlamps properly adjusted, but at least the motorist should train himself to keep his eyes away from them to a certain extent. When a car is driven with one lamp pointing diagonally across to the offside, nothing approaching drivers can do will keep the bea.in put of their eyes. With the lamps pointing straight ahead, as they should be, care should ho taken to 6ee that the tops of the beams are fairly flat and not directed up in the air. Always be sure to carry at least one spare headlamp and one spare tail lamp bulb.

“SLEEVED” TYRES. When a tyre i 6 gashed open by a jagged, broken bottle, or some other sharp impediment in the roadway, the cut will have to he vulcanised on the outside and the inside “sleeved” so that water and dirt will not be able to enter and rot the cord carcase. When this is done, it is possible to obtain a considerable additional mileage from the damaged tyre, but the motorist must remember that the repair will throw the wheel badly out of balance. While it may quite safely be used on a back wheel, its use on the front is inadvisable, owing to the danger that it may cause wheel-wobble unless the wheel is balanced carefully by adding weights to various parts of the rim. The tyre will also have to "be watched ca.refully, as the repaired portion will wear more rapidly than the remainder of the tread. If it is forgotten, the tyre may eventually blow out at the weak point. SALES IN AUSTRALIA. During the first quarter of 1937 13,974 cars and 4372 commercial vehicles —a total of 18.346 —were sold in Australia, compared with 13,157 cars and 4356 commercial vehicles, for the first quarter of 1936—a total of 17,513. New South Wales was the largest buyer, taking 6025 ca.rs and 1757 commercial vehicles out of this total. Victoria purchased 4228 new cars and 1195 commercial vehicles, while the respective figures for Queensland were 1328 iand 676; for Western Australia, 576 and 138, and for Tasmania, 416 and 154. A surprising feature of the figures is that most of the improvement was accounted for in New South Wales, while a. greater proportion of cars to commercial vehicles were sold than was the case last year. TYRE WEAR. LONGER LIFE IN WINTER. One of the large manufacturers of tyres has stated that a deep non-skid tread is not the only advantage to be derived from fitting new tyre6 in winter. It is pointed out that most of the tyre wear occurs in summer, due to the damaging effect of heat on rubber. Inversely, the cold air and cold roads of winter cause very little damage to a tyre, a fact which induced the engineers of this particular company to study the question more closely. As a result of their experiments, the following statement was issued :

“Tyres broken in on the cold roads of winter actually ‘cold cure’ themselves, and enter the spring and summer driving season showing very little wear. Since the average motorist does about 30 per cent, of his driving during the late autumn and the winter, he actually gets this 30 per cent, of his mileage free and adds this to the total mileage his tyres deliver.” In the case of one car which covers a fairly, big mileage, the rate of tyre wear during the winter has been noticeably slower than it was during the summer, and the fact has been commented on, but the reason not known until the foregoing statement was received. FAULTS IN IGNITION.

A misfiring plug, particularly one suffering from an intermittent fault, is often difficult to locate, especially in the case of a six-cylinder engine. If the suspected misfire should occur at some particular speed (probably at a slow tick-over), set the throttle to hold this speed steadily and then allow the engine to cool down so that the plugs are all fairly cold. Start up the engine and allow it to run for some minutes. The faulty plug will then feel appreciably cooler to the touch than the others. When a misfire is duo to oil jon the plug, it is sometimes possible to put it right by bolding the high-ten-sion wire about a quarter of an inch away from the plug terminal while the engine is running, allowing the spark to jump across. A few years ago many external gaps on this principle were sold as “spark intensifiers.” With the advent of coil ignition the spark-gap terminal was no longer in demand, hut its use can be justified on many engines with magneto ignition. Plug terminal nuts, if lost, never need he a cause of worry, for if the cable is given a twist it will never jump off the plug, yet it can be removed or replaced while the engine is running, and thus a quick method of observing whether a spark is passing is provided.