THE MOTOR WORLD.

Star (Christchurch), Issue 16413, 29 April 1921, Page 6

THE MOTOR WORLD.

NEWB AND NOTES.

j (By * RADIATOR.”) Many people have an idea that the nie of a first-class car is a matter of two or three years, but in the case of urst-class British and European cars such far from being the ‘case, and many English-made cars are -till giving excellent service on Australasian roads —although they have been in continual use for eight or ten years. In this connection some very interesting data woe recently pubished in England in reference to the cost of running a 1420 h.p. Woisoley, by Lieutenant-Colonel Inn Forbes, from 19(39 to 1920; with the exception of 1918, when the owner was on active service. In eleven, years the distance travelled was 47,130 miles, th© average petrol consumption being 20.3 miles per gallon, of which 2307 gallons were used, costing £l3 13s foi« petrol for 5713 miles in 1909, os against £3l 6s for 3736 miles in 1920. Tyres for the eleven years cost £l9B 3s, oil and grease £2O, licenses and insurance £156 11s 2d, repairs £llß Is, the whole cost totaling £691 10a 4d, an ax'erago of £62 17s 3d per year for the eleven years’ service of th© car. The difference in the running cost per mile well illustrates th© increases that have occurred during the period 1909-1920 — the figures being: 1909, 1.5 penny per mile ; 1910, 3d per mile ; 1911, 2.5 ; 1914, 2.4; 1913, 6d per mile; the big jump being attributable to a thorough overhaul of car, costing £69 19s; 1914, 2.5; 1915, 4.5; 1916, 4.5; 1917, 4-8; 1919, 6d ; 1920, 5.3. The total weight of car is 23 cwt. The only breakages during the period weite the back brake rod snapped twice; whilst on two occasons the bolts securing the front springs to axle broke, and two broken fan belts. Th© original cost of the car was £6OO. Here is a good illustration of what a high grade English car will do in the hands of a man who givea his car proper care and attention.

The car owner who carries a spare tyre—and a great many of them do—unprotected on the car is laying up trouble for himself. Even if no more serious accident happens, dust collects on the inside of the spare casing and is turned to mud by the first shower. Then -when the casing is called into service the inner tube will be rubbed against the hard deposit of mud, with chafing and a speedv blow-out is the result. Cases for the spare tyres cost little, and they should always be used to protect and preserve tho spare tyre for its day of service.

The average motorist knows considerably more about dozens of parts in his car than he does about his tyres, even though a tyre has only five principal parts. These are the careaea, the tread, the bead, the sidewall, and the breaker strip. The carcass is made of layers or plies of fabric impregnated with rubber. Fabric is used to give the casing tensile strength, while the rubber holds it together and gives it wearing qualities. The bead gives shape to the tyre and anchors it to the rim- In the clincher tyre this bead is made of elastic rubber, as it must stretch in order to get the tyre on the rim. In the straight side tyre, the bead is made of a wire cable imbedded in hard rubber, as the rim may be slit to mount tho tyre. Here there is no need of stretching. The side wall is the light rubber covering on the sides of the tyre as far as tho tread. Ita purpose is to protect the carcass from injury by the elements. The breaker strip supplies the maximum amount of resiliency between the tread and the carcass. It is just under the tread, and is made of web-woven fabric imbedded in cushion guin. It firmly rivets tread and carcass. The tread is the running surface of tho tyre. It is made of heavy rubber carefully compounded to give the maximum wearing qualities. A design is moulded in tho tread for traction purposes.

Little does the average car owner realise the tremendous forces unleashed when he starts the engine of his automobile. An English scientist Recently made some interesting calculations in this connection. He found that a piston with a strokeof ssin at a engine speed of 4QOO revolutions a minute forr six cylinders travels 72 miles and hour. During a 200-inile trip the piston, weighing just under a pound, goes up and down in its cylinder 585,000 times. During such a run the radiator dissipates enough heat to boil tea kettles in 450 homes. Each spring moves up and down at least 400,000 times during a 200-mile jaunt over average improved roads. Consider the breaking mechanism; When a car which, with passengers, weighs 4000 pounds is brought to a stop from 50 miles an hour, the energy dissipated would lift tho largest type of steam locomotive in existence several inches in the air. The generator during a four-hour rim of average speed will put fire amperes into the battery at six volts—energy enough to illuminate a trans-Atlantic liner for a full minute.

As a general rule, knocking is due to over-heating or excessive carbon deposits, if it not produced b yworn bearings, damaged cylinders., or other mechanical parts. Knocking due to carbon can be readily prevented by eliminating the cause—cleaning them out as frequently us may be necessary. Of course, knocking due to worn bearings can only be prevented by properly taking up the looseness. Knocking due to over-heating can be prevented by making sure that there is an ample supply of the proper gffade of lubricating oil in the engine, that the fan-driving belt is tight, that the radiator is cleaned and none of tho hose connections buckled to prevent proper flow of water, that the water pump is circulating the coolling liquid and that the radiator is kept properly filled with water.