MOTORING

Hawera Star, Volume XLIX, 31 August 1929, Page 15

MOTORING

A SINGLE OPERATION. DOUBLE DECLUTCHINGS. HOW IT IS DONE. t “Double declutching ’’ is a term applied to a method employed in changing gears of the type commonly used ■in modern motor-cars. Its employment is not as common as one might expect, but the driver who is keen •to develop “good hands’'’ very early acquires the knaak of using this method and nothing else. It can (be taken for granted .that double declutch. in,g means a very much easier task foT the gears throughout the life of the ear because they will not (lie damaged in any way through ‘bad changing once the driver has learned the succession of events that, go to make up the complete movement. Actually what occurs is:—

(1) The clutch pedal is depressed and held down while ■ (2) The gear shift lever is moved •into neutral, then (3) The clutch pedal is released. (4) The engine is “revved up” by depressing the accelerator until its speed is comparatively high. ('o) The accelerator pedal is released and the clutch pedal depressed and held down while (6) The gear shift lever is moved into the next lower gear, then (7) 1 'The clutch pedal is released, and car speed controlled, as usual, iby the accelerator.

This is a simple operation, and if desired can quite easily be practised upon a stationary car before practising it with the ~ ear in motion. It should be borne in mind, however, that ■the reason why some drivers find it rather difficult at first to acquire skill in double declutching is simply the result of a natural hesitancy about speeding up the engine while none of the gears is engaged. .Others, again, object to a “racing” engine, but .the experimenter in commencing to learn double declutching must side-tract such objections until practice 'teaches just how much acceleration of the “free” engine is required. He can derive a lot of help from the recollection .throughout his practising that, first, the speed at which the car is travelling when the -change is made does not matter at all, and, second, the movements must be gently but deliberately made. Naturally, a practised driver in changing flown at high speed will go through the motions in. a shorter time than he would were he to change down at a low ear speed, but the movements will never be hurried or jerky. The novice -cannot do better than to •get his car on to preferably a level road after getting a .thorough grasp of the succession of events mentioned above, and there applying what he re- i members. Do not have more than 15 rn.p.h. on the speedometer when thei initial attempt is made; but not hurry the motions, and do not be afraid of * ‘revving up” the engine for the short period that the gear shift lever is actually in neutral. The main thing to strive for is a knowledge of just when to release the accelerator before engaging the lower geaT. Changing •down, then, from second to low will require more engine speed prior to engagements of low gear than will be the ease in changing down from high to second. The ‘‘‘key” to a quiet change is engine speed, which fact will become apparent very early in practising double declutching. When the rudiments, have been mastered and slow changes have been made speed up the car a little, but bear in •mind that, as the speed at which the change is to be made increases, the shorter must be the interval between the depression of the clutch spedal as in (5) above, and the movement of the gear-shift lever into second, or low, as in (6). When confidence is acquired after practising on the flat, take the car into the neighbourhood of a hill. Approach the hill at, say, 20 rn.p.h. in high gear, and as the car rises on the gradient—i.e., without waiting for momentum t-.o be lost, practise the change down. This will increase the driver’s confidence, and will demonstrate that he is capable of changing down by double declutching on a climb—if he can do it at low speed at the bottom of the hill, he can do it at any other point .on the hill, and low car speed will result as the neutral effect of the grade •’(which makes it necessary to change down). After this a good finishing off can be •obtained by driving to the erest of a •hill and changing down by exactly the same procedure, as the car dips down the gradient. In this case a little more determination will be required in voluntarily Tevving up the engine

while the car is being pulled, down the grade by gravity, but if .the driver can do it on .the flat and on a iclimb, he can do it just as well going down hill. This method, as a -habit in changing down, has its advantages. It applies over quite a wide range of -ears, and enable the driver to get more satisfaction from the use of low horsepower, because it entirely eradicates that which to. so many motorists is a bugbear—i.e., jerky and uneven gearchanging.

HINTS. THE CAKE OF THE CAR. SOAP AND WATER. Soap and .water are better than petrol or paraffin when it comes to cleaning fabric or rubber-covered running boards. They may not do the job so guickly. and perhaps more energy is required to do it thoroughly, but the material, particularly if it is rubber, will not- rot or crack nearly so quickly as when petrol is employed. Furthermore, water will not damage the paintwork if it is splashed about STICKING PLATE CLUTCH. A defect frequently. encountered with plate clutches is failure to disengage. fully, particularly when cold. Consequently there is considerable difficulty in engaging first gear A simple tip is to depress the clutch fully, move the gear level until the reverse gear teeth can just be felt touching, and then move the lever back rapidly into first gear position. First gear then engages silently in the majority of cases. SILENCING THE BONNET. 1 When a car becomes old the bonnet usually starts to rattle, and this is because the packing strips fastened to the radiator and scuttle have worn down, so that the bonnet has become loose. One way of remedying the trouble is to fit new packing strips, but a simpler method is to put small pieces of leather underneath each loop in the packing strips, so that in effect they are thickened, and the bonnet is restored to its original tightness. When the work is completed, make sure that the bonnet edges clear the boards to which are fastened the clips, for it is at these points that the rattle usually arises. PETROL GAUGE. It is sometimes useful in the case of a car with a glass-tube type of petrol gauge to be able to take readings of the petrol level before and after a run to see how much the level has fallen. Most owners can approximate the amount of petrol indicated by an inch on the tubing, and it is, therefore, easy for them to estimate their miles per gallon. A simple device which will help them in this respect is the fitting of a “tally” in the shape of a cheap fountain-pen clip of suitable size, the arm of which has been removed with a file. It should be sprung on to the shroud of the gauge glass so that it can be slid up and down. Before the run it should be set to the fuel level indicated in the gauge, and at the end the difference in the level will easily be seen.

CAR MAKERS. MEN WHO HAVE SUCCEEDED,

The manufacture of motor-cars may be said to have begun as an industry approximately 25 years ago. At the start it'was a matter of individual initiative. Independently and in associated groups, various men with ideas and energy began making motor cars. Some of them .dropped out as the years passed, new companies and new men came in, until the motor .vehicle scene to-day is quite different in its aspect and'personnel from that of 25 years ago. The change has been gradual, however, and it is noteworthy .that a large percentage of men at the -head of affairs to-day have grown up in the business. Eve'n .those who came into the field of production after the industry had established itself entered inconspicuously in minor roles and reached positions of importance by climbing the ladders of their own factories. Most of them came up from the bottom. Few landed from the outside on top. In England, amongst others, notable examples of such men are to (be found in the cases of Sir William Morris, Sir Herbert Austin, and Mr Henry Boy.ee of Bolls-Boyce fame, while in (America in addition to Henry Ford, names such as iC. W. Nash, Erskine (the iStudebaker leader), and John Willys, -come to mind as having been connected with the industry at one time in a small way. Probably Walter P. Chrysler is the most outstanding example .of a man entering the motor industry comparatively recently and making a huge success of his venture.