Motor Notes

Wanganui Chronicle, Volume LXXVI, Issue 18533, 15 July 1922, Page 8

Motor Notes

By

“PLUG”

TROUBLE IN DRIVE GEARS. It is a common thing for the bevel gears of the final drive a motor car to develop a howl after repairs have been made. When the bearings have worn gradually the gears spread gradually apart so that the teeth do not mesh together to the proper depth. As a result, the teeth do not wear to improper shape, sometimes developing a slight shoulder where the tip of the opposing tooth comes. When new bearings are installed or the old ones adjusted, as the case may be, the worn teeth are made to mesh more deeply, but due to the irregular shape they do not engage and disengage smoothly, and howling is the result. There always is a possibility too. that after the repairs have been made the gears will not be meshed properly. Howling is more often due to meshing too tight than to meshing too loose. In the case of bevel gears, there are two ways in which the adjustment may be too close. Either the pinion may be too far along on its shaft so that the pinion teeth, which are tapered, wedge between the teeth of the ring gear, or the ring gear may be too far along on its shaft, causing the teeth to mesh too deeply. These gears usually are made so that the large end or heel of the teeth on the pinion will come just flush with the corresponding end of the teeth on the ring gear, while the adjustment or position of the ring gear is judged by the amount o£ shake between the gear teeth or by adjusting them so that a very thin street of paper can be passed through the gears without making them bind. The exact adjustment of the final drive gears is not so easy to determine in the Ford as in some other ears, and for this reason adjustment may not be made with sufficient accuracy. If the thrust washers at the left side of the differential were replaced, their additional thickness, together with the closer adjustment of the pinion due to replacement of the rear driveshaft bearing would be very likely to make the gear noisy, especially if the old drive shaft pinion were used. Some excellent repairmen make it a practise never to replace one of these gears without replacing tlie other also. They say that it is almost impossible to put a new pinion to work with an old ring gear, or vice versa, without have the combination howl and cause a ’dissatisfied customer.

If the drive shaft of a car is sprung it would have a tendency to make the pinion run a little out of centre, and in this case the howl would be of varying intensity as the pinion turned. These variations would be in unison with the revolutions of the engine, while it the ring gear were out of tune, the variations would be in unison with the revolutions of the rear wheel.

The lubrication of these gears has a very important effect on how quietly they run as well as the durability of the gears and bearings. Owing to the tendency of a heavy-bodied transmission oil to work out of the differential housing into the brake drum and on to the tire, many persons use a grease as a rear axle lubricant. In some cases the grease is so stiff that the gears cut a track through it much as they would through soap, and neither the gear teeth nor the bearings receive any lubrication worth mentioning. In other cases the oil, upon which the lubricating properties of the grease depends, is of light body, and consequently altogether unfitted to gear lubrication. A very thin oil may be used in a very stiff grease, while if a grease must be used, it should have just the opposite properties. There are cases in which the addition of one or two heaping teaspoonfuls of high-grade, fine lubricating graphite to the rear axle lubricant has produced a striking reduction in the tendency of the gears to howl.

NOVELTY AND NEGLECT. A cartoon, t’hat went through a section of the comic press recently showed a man carefully dusting’his new car and worrying because there was a speck of dirt on it. Then there was a blank left to indicate the flight of time, and then the final picture. Here the same man was shown in a car covered with dirt and mud, while a by-stander says: “Mister, your car looks awful,” to which the man replies: “I don't care as long as it runs." There was as much truth as comedy j pictured in the comic. That man, j when his car was new. was also extremely careful to fill his grease icups regularly; tb'keep his radiator I filled, and, in short, do all he should do to take proper care of his car, and, unfortunately, when he became careless' about the looks of his car, he also began to neglect the mechanical parts of it, and now seldom fills his grease cups, and is content- | cd as lon# as the car Funs. I If, when a spring, or steering mechanism bolt breaks on this man’s (car. he be told that it broke because lof his neglect, and not because of la defect, he would probably become 'quite indignant. I THE SCIENCE OF LUBRICATION. ' You may sometimes feel that i about twenty-nine of the horses are dead in your 30-horsepower machine, nevertheless that machine will do as much work for you as thirty horses could do; it will carry you 200 miles a day; it will take you further in five minutes than a horse will in half an hour, without counting the time taken to harness. So

why not give a little of the time required for harnessing one horse to the lubricating of the equivalent of thirty horses? The starting and lighting system is automatic and requires little attention but it is electrically operated; which means that by incorrect use it will quickly go wrong. Owners should never do anything with any part of it, even to the taking out of the battery, without first studying the instruction book furnished by the maker.

Many cars, especially those equipped with a magneto, require that certain wires be disconnected from the generator when lhe battery is taken out to be charged, as if the engine is run without the battery, the lights will be burned out, and pos-

' sibly the generator be ruined. Instruction as to how to do this will be given in the book, and possibly there may be some other precaution of a similar nature which you must take. Save Repair Bills. You will not. err by giving too much oil, as asUle, but there is one kind of mechanism, to which much damage can be done by giving too much oil. This is in Connection with the electrical instruments, such as the magneto, the generator and the startng motor. Too much oil here may cause a bad circuit and one which is hard to locate and repair. Be sure that you have read the paragraph in your instruction book on the lubricating of these parts. In many systems, a drop or two once a month is enough. With the advent of the electric starter the use of the spark advance end retard lever has been much neglected. You would not crank your engine by hand with the spark advanced for fear that it kick back and hurt you. So, why make the starting motor run the risk of being hurt by starting the engine with the spark advanced? Many a man has started his car in this way hundreds of times, and then one day when the condition was just right the engine kicked back and stripped the teeth off the flywheel or ruined the starting motor. This meant a repair bill in the neighbourhood of 50 dollars.

GENERATOR TROUBLE. C. M. W.. Ont.—l have a 1920 car ol which the generator has been giving some trouble. When going at full speed the ammeter only registers a rate of six amperes, while I understand that to keep the battery in good shape it should be 10 ampere. 1 found that, 'by moving one of the brushes that I could obtain a charging rate of from 5 to 2 0 amperes, according to the direction 1 moved it. How should I go aboui to grind the valves on my car? How often should it be done? Ans. —You have discovered the proper method of adjusting the charging rate of the battery and what you should do is to move this brush until the rate is about 10 ampere. Just when the valves of a car should be ground does not depend on time, but on the condition of the valves. Careless, operation of a car may result in loose fitting of the valves on their seats. As a rule they should be ground each year. When this is done by hand one uses a special bit in an ordinary brace. This bit two points on one end to engage into the two small holes on the valve. A mixture of vaseline and fine emery powder is used for the ebrasive and is placed between the valves and their seats. It is perhaps better to buy this compound ready mixed. When turning the valves they are not turned around and around but are turned about quarter way and back again several times and are then lifted up and turned half way around, set down again and 11 : grinding continued until any pits or dull places on the valve seat and face disappear. Care should be taken to clean away all the grinding compound and not allow any of it to get into the cylinder. We take it for granted that you know that the radiator must be drained, the cylinder head removed and the valve covers on the right side of the engine removed. \ Valve springs must also be removed.

LOCATE SUSPECTED TROUBLE. L.E.F., Ont.—The timer of my Ford is not working right. The engine misses badly if speeded up, with the spark advanced, although it runs fairly well with the spark retarded. It will not idle down, either on advanced or retarded ignition. What do you suggest? Ans.—lf you ' are sure that the timer is where the trouble is, you might as well replace it at once, also installing new timer wiring if there seems to be any possibility of broken or short-circuited wires. It seems qubte possible to us that there is trouble elsewhere than in your timer for as a general rule a fauliy timer affects high speed operation but does not so often interfere with slow idling. Before installing a new timer, you had better make sure 'that the magneto is normally strong and that it has a good contact; that plug-gaps and vibrator adjustments are 0.K.; that there are no loose primary connections ' and that there are no defects in any of the wiring. Your trouble may not be due to ignition at all, but may be from carburation defects—such as air-leakage —or even faulty valve action.

POWER LOST THROUGH WATER COOLER. The automobile engine is a notorious heat waster, though it is. strictly speaking, a heat engine and therefore should not waste any heat, or as little as possible. Yet fully one-third of the heat generated (and the heat is power) is lost by being ; passed to the cooling water. Now i when water is sent into the cylinders upon the intake stroke the charge is naturally cooled. On compression it is heated and upon explosion it is turned into steam, thereby taking away some of lhe heat which would ordinarily be wasted by passing through the water jacket into the water. Later on in the power stroke, when the power on the'piston is reduced the steam gives up its heal in the greater part and thus helps put some more power where it is needed. In other words, during the early part of the explosion stroke the water prevents a heat loss by taking some of the heat into the mixture only to give it up later when the beat is needed in lhe cylinder. This explanation may be taken as being correct with the theory as to waler- decomposition wrong.

THE TRAINED EAR. In a room full of running motors, an inspector can detect any unusual sound in a single engine by putting his ear to the tip of the .gear shifting lever. That’s -because he knows the note of a perfect motor. Besides, each particular kind of unusual sound will tell the inspector exactly where it comes from. His ears are trained to distinguish such sounds and locate them. But for those whose ears aren't as keen as the motor Inspector’s, there is another kind of divining rod. it is a p.ece of broomstick or other wood. Or it may be a long screw driver. With this simple divining rod foreign noises can be detected not only in the engine but in any other moving part of the automobile. The method of application is simple. Place one end of the rod against the part which is suspected of making the unusual noise. Then put the free end in the crook of the thumb and the thumb knuckle against the ear drum. If the part runs smoothly and nothing is wrong with it, a regular hum will be heard. Otherwise, the hum will be interrupted by a knock or other strange sound. In this way, -any fault in the running of the automobile can be located by moving the divining rod from one position to another. Sometimes location of a fault is iftore difficult than its correction after it is found.