MOTORDOM

Greymouth Evening Star, 3 July 1936, Page 9

MOTORDOM

NEWS OF THE ROAD

(By

“Gearbox”)

electrical faults.

PREVENTION BETTER THAN CURE

Recently figures issued by the Royal Automobile Club of Great Britain, dealing with the causes of road breakdown, showed that by far the greatest number of involuntary stoppages has been caused by the electrical equipment. That part of it providing ignition had been the chief offender. The same is true in this country, and although in these days hold-ups by the roadside are rare, when they do occur more often than not they traced to the ignition or some other part of the electrical system. Many owners are quite willing to make an attempt to cure any obscure mechanical trouble, but when they know beyond any shadow of doubt that the fault is electrical they are overcome by a feeling of extreme helplessness and will not dare to touch any part of the system themselves. In this they are possibly right if they are ignorant of the whole apparently involved system, but certain faults which may arise can easily be dealt with by the owner if he troubles to leam some elementary facts about it. Better still, if the motorist would carefully digest the hints given in this article and follow the advice offered the electrical system of his car will always be in such good order that the possibility of trouble arising on the road will be largely negatived. Prevention is always better than cure. The amount of attention the system requires is small, so that the owner is not faced "with a difficult task that must bo carried, out at frequent intervals.

Probably the most important unit in the electrical system is the battery, for on its efficiency depend ignition, starting, and lighting. Because of its construction and the work it performs, it requires attention more frequently than any other part. However, this only involves “topping up” the cells with distilled water about once a fortnight, so that the level of the water is a little above the tops of the plates, but not to the necks of the filling orifices. An air space between the water and the top of the battery casing is required. If necessary, an electric torch can be used to determine the level of the water in tire cells, but. on no account use a naked flume, as a battery generates gas and an explosion might occur. CORROSION DANGERS. After this has been done the filler caps should bo replaced and the top of the battery carefully wiped clean and the terminals smeared with, vaseline to prevent corrosion. If any corrosion has occurerd it should be carefully scraped away.

The generator and the starting motor seldom require attention ; beyond a little lubrication in the mariner advised in the car’s instruction book, but two or three times a year it is as well to remove the metal strip encasing the brush gear on both, so that this gear and the commutators can be cleaned. Carbon and metal dust should be blown or wiped away with a soft cloth, and the brushes should be pulled, out and let go to determine whether they are moving freely in their holders. If one of the brushes sticks it can be eased by rubbing down the high spots.' The best method of cleaning the commutators is to hold a soft cloth against them while the armatures are being turned, and a piece of wood shaped to conform to the curvature of the commutator will be found useful to press the cloth against it. The grooves between the segments of the commutator may possibly catch dust and carbon, and they can be cleaned by running the end of a broken hacksaw blade gently through them. However, should the commutator be in very bad condition due to neglect, it is much the better plan to allow a service station to attend to it.

Occasionally remove the cover of the distributor and wipe away any dust with a’soft cloth. Clean the electrodes with a cloth moistened with petrol, and also make sure that the carbon brush in tho centre of the distributor moves freely in its holder. In the modern car the contact breaker points will turn and blacken fairly rapidly, so that they should b-e looked at every 3,000 miles to be on the sate side. If they are in this state they may be carefully trimmed up with a special smooth file or a carborundum stone, and particles of dust being afterwards wiped away with a petrol moistened cloth. Then the points should be adjusted carefully to the correct gap by the feeler gauge generally provided in the tool kit. The correct gap is .015 in. Give the cam which operates the rocker arm a smear of vaseline, and verj r occasionally—about everj r 5,000 miles —a single drop of thin machine oil may be given to tho pivot on which the contact breaker arm rocks.

Next, pay some attention to the sparking plugs, and. as is the case with the make and break mechanism, it may be found that they are affected fairly rapidly by modern high compressions and the high-ar operating heat in the combustion chambers, which these engender.

Take the plugs out every 1,000 or 4,000 miles, clean them of soot and carbon, and readjust the gaps to .018 in. with a feeler gauge. It will be found that the gaps are excessively wide, duo to the points burning away. In modern cars the wiring to the lamps, starter, and other parts of the electrical system is carried out very carefuly indeed, and the chance of some part of it chafing against metal portions of* the car is so remote as not to be worth considering. However, most cars use C!i-j sinsle-wirc system, in which the frame of the car itself is used as the return or negative wire, and. it is possible for a loose connection' to develop, due to a lamp or some other part which depends for a good electrical connection on the tightness with which it is bolted in place shaking loose. All the=e parts should be gone over occasionally with a spanner to make sure that they are tight, par-

ticular attention being paid to that short wire which runs from the negative terminal of the battery to a bolt in the chassis frame.

INCREASING POWER.

TESTS IN GREAT BRITAIN

There are many motor engineers who believe that the most practical way of increasing the output of motor engines is to employ a super-charger to provide a reserve of power for acceleration, and hill climbing. Some authorities go so far as saying that all touring cars of the future will be provided with forced induction, thereby insuring all the power that is needed without recourse to large sized engines. In the past, one of the obvious disadvantages of supercharging was the additional mechanical complexity which it involved, but, according to the latest reports from Britain and the Continent great improvement has been effected in the reliability and efficiency of the modern “blower.” With the object of obtaining data relative to the comparative performances of a touring car, with and without supercharging, some interesting trials were recently conducted on English roads, and on the Brooklands track, London. The car used was a six-cylinder 20 li.p. Alvis, the machine having covered some 16,000 miles before tho tests were conducted, the first 10,000 miles without a “blower.” The effect of the forced induction on the car can be summarised by saying that the accleration on top gear (4.55 to 1) from 10 to 60 m.p.h., was almost identical with the acceleration formerly obtained on the third gear ratio (6.53 to 1). This improvement, in power output indicated that the 2762 c.c. engine with “blower” fitted, gave a performance equivalent to an engine of 4000 c.c. capacity. One of the outstanding advantages on the road was found to be the great improvement in top gear performance as regards the facility and safety with which the car could overtake other vehicles on a winding road. The tractability of the car at low speeds on top gear in traffic was improved, as also' was hill climbing. Under equivalent running conditions fuel consumption was about 10 per cent, higher with forced induction. Maximum speed was about 10 m.p.h. faster without any change in back axle gear ratio. The final conclusion from the test figures were a 50 per cent, increase in liveliness in return for adding 1.7 .per cent, to the total weight of the car and 121 per cent .to the average fuel bill, a result which is claimed to justify the extra cost, and complexity to those motorists who appreciate, performance. In Great Britain many private motorists arc having their machines equipped with “blowers.” The outfits aro compact, weight about 561 b., and can be attached to most modern cars without a deal of trouble. In most cases, special exhaust valves are fitted in order to cope with the increased volume of mixture burnt at full throttle.

It is reported that although car manufacturers in Europe and other parts of the world are not displaying much overt interest in supercharging, experiments are proceeding behind the scenes, which may bring about developments in the not distant future.

“SAFE” SPEEDS

Attention to the danger of slowmoving traffic on the roads was drawn recently by the executive of the Automobile Association (Hawke’s Bay) when a discussion arose over the recent declaration of war on “road hogs” by the Minister of Transport (Mr. R. Semple). “These virtuous old gentlemen doing 20 miles an hour and patting themselves on the back because they are observing the speed rules of the road are creating a menace to other users of tho highways,” said Mr. J. IT. Edmundson. “It often happens the drivers of these slow vehicles are as much to blame in an accident as the man who is probably doing 40 miles an hour. It is a more heinous offence for a man to do 5 miles an hour on (lie wrong side of the road than for a man to tarvel at a decent pace on his correct side. “While we as an association want to encourage safety first, the ideal on which that safety is based is what might be termed the prevailing idea of a safe speed,” he continued. “If that speed is 30 miles an hour or -even 40, then the man who travels at 20 is probably a greater cause of accident.”

Mr. R. M. Chadwick: "The most dangerous factor, I think, is th-3 failure to keep to the left when turning corners. The man who drives fast is not necessarily it ‘road hog.' The driver who takes a corner at 5 miles an hour cannot get out of the way as quickly as a man doing an average speed.