Economy in Fuel

Ladies' Mirror, Volume 4, Issue 8, 1 February 1926, Page 35

Economy in Fuel

pETROL economy is practically a * closed book to the average own-er-driver, for while driving for economy may effect a marked difference in the consumption, it is quite evident that this must first be reduced to the minimum by careful tuning, so that the method of driving is rather resorted to in order to improve an already good consumption than merely to lessen one which is frankly bad. Nothing runs away with more petrol than a binding brake. All the time friction is occurring, and all the time the throttle has to be open a little wider in_ order to overcome the retarding effect. To a lesser extent lack of lubricant, whether engine or chassis, will cause friction where there should be none, and up consumption will go. Therefore the first essential is to examine the wheel brakes to see that they are absolutely free, and to grease the wheel bearings in order that there may be no drag at these points. The car should be capable of running free for some distance with the gear in neutral, and should be quite easy, if it is a fairly light vehicle, to push by hand on a smooth, level surface. 'THE gearbox and back axle should be drained of old oil, washed out with paraffin, and refilled with fresh lubricant of as light a grade as is possible without risking oil leakage. This is in order to avoid the waste of power which results when gear wheels in the gearbox and back axle have to churn their way through stiff, heavy lubricant. As regards the engine, this should be clean internally and free from carbon. If it has not been decarbonised for a long time the work should be carried out before attempts are made to get a very small fuel consumption. When the engine is decarbonised the valves should be ground in very carefully, especially if they are badly pitted. The inlet-valve stems should be inspected to see if they or the guides in which they work are worn, for if they are air will leak in round the stems, and in order to overcome its effects a richer

mixture would have to be given, with poor consumption as a result. Some good grinding paste should be used, a very fine grade being employed to finish off with; while a final polish can be given with effect by smearing crocus powder or metal polish on the seats and giving the valves a few turns. The mirror-like surface of new valves is the ideal to be aimed at, but much patient work is necessary before it can be attained. TF the valve stems or guides are worn they will have to be replaced, but a temporary method which often gives excellent results is to fit air-leak preventers, such as are sold in a variety of patterns, round the base of the valve .guides. These air-leak preventers consist of small thimbles containing pads of felt soaked in graphite and oil, held against the guide by a light spring. Fitted to a new engine, they tend to prevent the wear which inevitably occurs on the steams. Smaller jets in the carburettor should be experimented with. It will be found that the engine takes longer to warm up, and that the acceleration is not all that it might be. the same being applicable to hill-climb-ing. It is for the driver to decide whether extreme economy is worth the sacrifice of acceleration and power which it demands. Sometimes changing of the jets means changing of the choke also. Good carburation may be cancelled out, as it were, by poor ignition. The contact-breaker points should be clean and separated to the correct distances on the break. The distributor should be cleaned and the con-tact-breaker rocker looked at to see if it is free on its spindle. The sparking plugs should be taken out and cleaned thoroughly. If they have given symptoms, or show signs when dismantled, of internal sparking, they should be replaced. Finally, valve caps, if they are fitted, should be screwed down tightly, and all chances of air or compression leaks occurring eliminated.

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