EXTRA AIR INLETS.

Evening Post, Volume CVII, Issue 82, 5 April 1924, Page 23

EXTRA AIR INLETS.

Correspondence on thesubject of extraair inlets has been published recently in "The 'Motor"; and one of the most interesting contributions' on the subject is from a writer who believes in plenty of opening in this useful addition to engine equipment. No one else, he remarkSj appears to have stressed the most cssentral function of an extra-air device, and 'that is the supplying of sufficient air totally to. drown out any petrol from the jet when running fast. We have uaed eifcra-air devices for many years, but hone on the market possess the desideratum mentioned above. They will stop the engine when running slow, but the majority will neither kill the petrol flow nor admit enough air when coasting down steep hills or running iast on the road. We always use one which has— when fully open—very nearly the same area as the inlet-valve port at full qpcninj;. By this ! means the valve absolutely precludes, the possibility of petrol ■ ; being used when.:fully open—it makes a very effective air brake and; engine cooler, :arid a very good "decelerator" in emergencies.

With. aiv efficient extra-air valve, the carburettor/may-be. set' for "sure and certain'1 starting, and slow running and wonderful economies effected by diluting the mixture simply by using the extraair lever as required. The extra-air valve make's an added saving, "in that no petrol whatever is used when coasting, and the valve may be opened and closed to suit varied running conditidris. There is no valve burning, and no popping back after the owner gets to know the amount,of opening necessary, which is much more easily done on a circular quadrant than' with a small handle or push-button on tho dash.-'

The only drawback to an extra-air valve is the liability absent-mindedly to leave it open in traffic, but by having it connected'to the1 mixture lever, one soon learns to use it without thinking, as, the hand is always on the spot. It seems absurd to have a throttle range of over 9J degrees on the carburettor control^ when no driver ever uses more than, six or seven teeth to start up or run the engine until- warnj. Why, therei fore, not utilise ' this for the extra-air valve t FRONT-WHEEL BRAKES. - If your car has front-wheel brakes, do not take any more risks than you would had you rear-wheel brakes only. Frontwhesl brakes are one of the greatest factors of safety it is possible to have, although at the same time, instead -of trying to-pull up in ordinary conditions twice as fast as you would be able to with rear-wheel brakes only, slow dqwn quite gradually, so that the fact that you have brakes on all four wheels means that you are using each set of linings only half as much as when you are using those. on the rear wheels only. • Rather should you look on four-wheel braking as. a means of lengthening the life ,-of brakes and brake linings/with, of course, the knowledge that should an emergency arise you can pull iip with amazing rapidity, but never forget that the driver following you may, rtot be able to pull up so quickly. Front-wheel brakes are no excuse for taking risks; reliable as. are most modern types, they might fail one day, so drive sensibly. BALLOON TIEES. ' , . Balloon tires that will fit present makes of cars without expensive change-over of ..wheels'-and rims are the newest contribution to the tire industry. There are more" people talking--about die balloon tire than any other new development in tires that has come along ■in years, says the "San. Francisco Chronicle." Its easy-riding- qualities have nade a powerful appeal to the imagina.<on of automobile owners. Balloon tires lave been adopted. as standard or optional equipment by a number of car nanufacturers. However, so keen, has j een the public interest in balloon tires hat thousands of motorists have gone ■ ■the expense of cutting-down or scraping their old wheel and rim equipment .1 order to get them. . ' The new interchangeable tire, which .-- .a balloon tire that will fit present ims arid wheels, will enable car owners •■■ho want balloon tires to-secure this ■quipment without going to the expense ■f wheel and rim change-over. No change at all is required in :traight side rims, and in the cases of ars equipped' with clincher rims only ! lie inexpensive change involved in subtituting straight • side rims for the lineher rims. . „- ■ • ECONOMICAL DRIVING. The • average man buys a car, gets rough idea of how to steer and control , and then, when his bills come in, Iscovcrs that, if is costing him, more iMn he originally . anticipated., He lames his carburettor for the inordinely large gasoline consumption. But if s car is a modern one, hia carburettor pUo-bly, will be all right. Proper ad-

I justment is' an' easy, matter, and the waste of gasoline from this source will not be appreciable. Unnecessarily rapid acceleration, driving too fast, too frequent use of the clutch, and erratic gear changing will most probably account for i tne power, wasted. For every movement f txie driver makes in a car jihere should be a reason, and every unnecessary manj ipulation oit^' the control levers' mean waste —whether of the energy supplied by tlie engine or of the life of tile, tires. The motorist should remember that the clutch is not a substitute for neutral. It is intended for use when- changing gears, and then only. The whole question of driving resolves itself into knowing what one is doing, why he is doing it, and what he is going to do next. The driver should keep his eyes and thoughts ahead of him, and let what he sees react upon the amount of power supplied to the back wheels. He should not be content simply to press his accelerator pedal right down, and I then trust to his brakes to get him out j of difficulties. He ought to observe everything remember that pedestrians have a habit of stepping suddenly off the pavement, thatj children dash out of byroads, that every bend conceals a,possible, obstruction, and that there is 00 canine rule of the road. "DON'TS" FOR THE GARAGE. . Don't take- a naked light near the car. Don't turn oh electric headlamps when the engine is stopped or throttled down. Don't run the engine with the garage all closed up—you may get "gassed." Don't turn the steering wheel with the car stationary. Don',t take the car out without verifying the inflation.of the tires: Don't take the car out without making sure that - there is pknty of petrol in the tank. Don't take the car out -without seeing that the engine contains plenty of lubri-, eating oil. ....-' Don't forget to screw down all the gr<2asers,-as recommended in the makers' lubricating chart. Don't forget to attend to the various ■parts of the qhaasis requiring attention with an oil can. (See makers' chart.) Don't take the ear but without inspecting the level of ths water in the radiator: .Don't take the car out without tools, especially pump, jack, and. tire outfit. Don't take the car out without spare sparking plugs. ,'" Don't pushidown the starting handle-^ pull it up. ' Don't move the gear lever without declutching. Don't forget to see if tho oil is circulating, as soon as the engine has started. . ]. " Don'fc forget to add distilled -waiter! weekly to the lighting accumulators, so that their plates are kept covered; ' Don't forget ;tq inspect -the .tires' for cuts, embedded stones, etc. ; ■ Don't go out without a spare tire valve. - ' Don't forget.to drain ,used oil out of" engine, gear bos, and'back axle once in each 1000 miles and to refill with recommended lubricants. . , ..Leaky Valve Hole Plugs.—An excellent means of curing leaky exhaust or intake valve hole plugs is by the use of graphite grease on. the threads. Not only 'will/the graphite grease cure leaking, but it will enable the plug to be readily removed and replaced. Position.—lt is impossible to make- a correct -carburettor adjustment unless the throttle closes . tight. ' To make sure that the throttle closes, first' operate the grip control to close position,, then try the carburettor throttle lever with the finsers. If it can then be ' closed further, adjust the control wire to get complete closing from the crip.. The -carburettor is then ready for adjustment. .Air -Leaks.—An.air leak in.the intake manifold will cause hard starting and irregular running. v .Hard Starting.—A worn-out condition' of the air, valve disc and shaft will result 111 a hard starting motor. If on removing the air valve, the disc is found to be loose on. the shaft, a new' shaft and disc should be fitted. motor-ctcllEng- notes: " If a rider gives proper attention to the' following details, he can save' enough on iys annual. upkeep to afford a thorough overhaul of his mount at the end of the season in the hands of a competent repair man. ,r Valve Adjustment.—A tight exhaust valve adjustment will cause a motor to run irregularly at idling speed. Tappets should be set with-six-thousandths clearance with motor cold. • . Setting Plug Points—Another cause of irregular running at idling speed maybe traced to one of the plug points being set too close.. The points in both plugs should be. set 'at uniform, distance of I thirty thousandths of an inch;