MOTOR AND CYCLE

Taranaki Daily News, 19 May 1928, Page 10

MOTOR AND CYCLE

NEWS CARS ON THE ROAD. FUEL TAXATION. (By Edwin Campbell.—Special to News.) London, May 29. The Ministry of Transport fact week issued a return showing the numbers of licensed motor vehicles of all kinds in use during the quarter ending September 30 last, together with an analysis which enables us to see how demand is affecting different categories. This discloses that fact that there were 786,610 motor ears licensed in 1927, as compared with 683,913 during the same period in 1926 an increase of 10'2,697. That must not be assumed to represent the total number of news ears that were put on the road in 19-27, as it is evident from the statistics supplied in the report that there must bo a considerable addition representing cars that have replaced those taken off the road, and probably scrapped for one reason or another. It i<? interesting to note that, apparently, there has been a general increase in all horse-power categories up to and including 18 h.p., but above that line decreases are more the rule than the exception. The obvious inference would appear to be that cars of more than 18 h.p. rating are losing popularity, but I am inclined to qualify any such conclusion by suggesting that owing to the relatively heavy taxation and insurance on these there has been a relatively larger scrapping of the older models than has been the case with lower horsepowers, One has only to exercise an intelligent observation on the various types of car in use to bo forced into the conclusion that there are as many of these "over 20 h.p.” models on the road as ever. I would not put it any higher than that, because the whole importation of American cars obviously is to ba included in this higher powered division, and while that does not amount to anything serious, taken in conjunction with the production of the dozen or so of British factories which turn out ears of 20 h.p. and higher denominations, one cannot conclude that ears oi this typo are going out of use more rapidly than production for the public demand compensates. PUZZLING DISCRI-:FANCIES. I have to confess that I find a difficulty in reconciling my -own ideas of the trend of affaire in the popular priced ear market, and the figures this report supplies, or in squaring them with the stated outputs of concerns specialising in ears of powers specifically indicated in this list. For instance, the increase® in the various categories during 1927 appear to be 8 h.p., 1,900; 9 h.p., 2.218; 10 h.p., 4,406; 11 h.p., 6,526; 12 ’ h.p. 29,193; 13 h.p., 15,572; 14 h.p., 20,3.58; 15 h.p., 3,874; 16 h.p., 583; 17 h.p., 974 and 18 h.p., 5,275. That gives a total increase of a trifle more than 1-07,000 ears, which, as my readers probably will recall, is not very much mors than a couple of the largest makers claim to produce between them. I believe that the trade census of production puts the number of new model® sold in this country last year at 141,01)0, but even with the addition that brings, the situation is still puzzling. I see it stated that the total claimed production of motor vehicles in America last year was over seven millions and three quarters, which must be very close to the total number of motors of all kinds in use in the world, so that these statistics of production and registration require a larger measure of reconciliation than a plain person can provide, unless we assume that somewhere there must be huge unsold stocks away, THE HORSE POWER TAX. Tlie Automobile Association’s petition to Parliament in favour of a return to fuel taxation, presented to the House of Commons on Tuesday last by Lieut. Col, C. K. Howard Bury, supported by members of all shades of political -opinion, contained no fewer than 920,000 signatures which must be very near a record for any petition of recent years. Last year’s petition contained but 360,000 signatures, so that it is quite evident that the tide is rising rapidly against the horse-power tax, and if it continues must compel the Treasury to give way. The organisation of the affair reflects great credit on the Automobile Association, but we must not lose sight of th® fact that it had in the main the enthusiastic assistance of the entire motor trade, to which the abandonment of the present system and it® substitution by one that would foster a larger volume of second-hand trade would mean much. LIEUT. KINKEAD-’S DEATH. The mystery of I’liglit-'Lieut. Kinkead’s death while attempting to create a new speed record in aeroplanee flight deepens. It is now stated that the poet-, mortem analysis of his tissues -disproves the suggestion that ho was poisoned 1 by either carbon monoxide or ethyl lead from his.exhaust fumes. Previous evidence at the inquest affirmed that he was dead when his machine struck the water, consequently he could not have been drowned, so that if he was neither poieoned nor drowned he must have been killed in some manner which apparently baffles conjecture. That he wa® not poisoned by exhaust fumee brings relief to those motorists who profees to have experienced discomfort from exhaust leakage into their covered cars, and probably will help to life the ban on ethyl petrol which many put on it after reading the first evidence given at the inquest. THE ETHYL CONTROVERSY. Dr. E, Maidlos \: ! d in interesting short article on the action of lead tetra-ethyl in Nature of March 17, in which lie states that although 900 million gallons of petrol containing 6 e.c. -of ethyl fluid per gallon have been consumed in too United States no illneee attributable to its use has been found. Also he states that the deleterious effect of the dope on the engine mechanism « negligible. Analysis of the lubricating oil and the carbon deposits in cylinder heads and exhaust system -of an engine after a 33 hour’s run accounted for 07.5 per cent, of the lead put into the petrol, of which 10.5 per cent, was found in the sump, about 23 per cent, in the cylinder heads, and 32.5 per cent, in the exhaust pipe, That would leave about 33 per cent, to be accounted for by -dissipation into the atmosphere, which, considering the almost negligible amount in weight it represents, is scarcely worth discussing in face of the much greater danger from

carbon monoxide. He gives a-n interesting set of figures showing the increase of power in an engine accruing wholly from increase in the -compression ratio, and also the permissible increase in that ratio by the addition of varying quantities -of lead ethyl to the fuel. Taking a compression ratio of 4 the indicated h.p. was 30. Increasing the ratio to 5 raises the power output to 33 'h.p. With a ratio of 6 it rises to 35, and at 7 it risee to nearly 37 h.p. Using pure petrol the highest useful compression ratio is 4.9. By adding five thousandths per cent, of ethyl-lead it is lifted to 5.3. By increasing the dose to one hundredth per cent, it rises to 5.7 With two hundredths it rises to 6.5. With three hundredths it rises to 7, and with four hundredths it rises to 7.35, a compression ratio greater than is now being employed in any motor car engine I believe. DECARBONISING THE ENGINE. JOB FOR AN EXPERT. London, February 10. One of the more common motoring queries from readers is that asking how soon and how a ear engine should be decarbonised, (says a motoring writer). Circumstances alter the ease materially, For example, the modern sleevevalve engine will frequently do 12,C00-15,000 15,000 mile® without requiring decarbonisation; some times a good deal more. The smaller the engine the sooner the need for -decarbonising—as a broad general rule. Then again, a high-eompression engine will need such attention sooner than one with a medium, or low compression ratio. Finally, the general design -of the motor has an important bearing on the subject—to eay nothing of the fuel and oil used. The best advice is to leave well alone until the engine begins to knock in ordinary -circumstances, and shows an appreciable falling-off in power. 2,000 OR 12,000. With the average ear that moment will vary within wide extremes —possibly between 2,000 and 12,000 miles. When decarbonising, is necessary, to wh-at extent ehould it be carried out! That, again, -depends on circumstances —on your skill and. knowledge if you are doing the job yourself, and on f. e. <l. if it is being done for you. It is not generally appreciated that the insides of the pistons become carbonised through the oil splashing, and that if it is bad it has ft serious -effect on the cooling of the engine. Obviously that part can only be got at by demounting the pistons. To take down, clean and successfully replace the pistons calle for more amateur repair ability than is general!. p" sessed, and is a job which should not oe tackled by an inexperienced person. IN TOP GEAR. INJURY TO ENGINE. Far too much stress is laid on. top gear performance in the advertising sales talk of many dealers, and the novice driver of a new ear naturally believes he is doing his engine no harm 'n hanging on to top gear to the last poosible yard. Gears were placed in a car for a specific purpose, and to be used intelligently. The new driver ehouhl remember that he must never let his engine labour up hill. A few hours’ han ’ling of a car will suffice to teach even the most inexpert driver when his engine begins to cry "enough.” As the ear slows down on the hill the sound of the engine change® from a pleasant hum to a distinct throb, and. the explosions can even sometimes be distinctly felt In the body. Not a moment should then be lost in changing down to a lower gear.

Even that, however, is bad driving, as the change should be made before the throbbing occurs, which is, as said before, an indication that labouring has already started. Over-driving on hills in too high a gear is one of the most prolific causes of undue wear on the crankshaft bearings and on the transmission generally, and agents—at least some of them—have themselves to blame for the bad name their cars earn in the hands of unskilled drive-s. Stress should be laid on the use of the gear level rather than on the "sensational” top gear performances.

DRIVING FOR TYRE ECOWW.Y. Tyre usefs are now experiencing and will continue to experience in the future a wide variation in tyre performance, regardless of the make or size of tyres used, states a tyre expert in the Goodyear News. A tyre which would give phenomenal service under certain conditions will give only a fraction of that mileage when used under other circumstances. This is not the result of a change in tyre construction, but to the continually changing motoring conditions. Some of these cireumstaces are: Higher powered cars This tends to quicker acceleration and quicker stopping of ears whieh grind off the tread rubber- of the tyre. Harder furfaiced roads, too, reduce tyro mileage as the road Is more abrasive and more heat is developed in the tyre.. Then again, the type of driver Is also a big factor. The conservative driver will get many more miles out of his tyres than the reckless driver. It ha» been proved that where the latter will only get 8,000 to 9,000 miles of service fiom his tyres the former is able to get 18,000 to 20,000 miles.