SOME MORE ENGINE TROUBLES.
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Difficulties Met and Overcome by Our Driver and Mechanic Readers.
WE HAVE -another batch of letters about engine troubles to discuss
this week. They are all interesting, and the choice of one deserving the extra 5s. prize money is not easy. We have, however, selected the one from " F.G.M." for that honour, and place it first in order.
This correspondent reminds us that most makes of heavy vehicle develop, after some months of wear, oil leakage from the engine tappets. The result is a dirty engine, which no engine-proud driver will tolerate if he. can avoid it. It also involves waste of oil, and increases the running costs of the lorry accordingly. Nevertheless, the wastage Is rarely sufficient to justify the outlay which would be involved in tha purchase of a new set of tappets and guides. Nor is such a purchase necessary if the plan advocated by him is followed. Ile tells us that on one engine which developed this trouble he adopted the following simple expedient, with complete success ;— A small tray was made from a sheet of tin, of the shape shown in the sketch, and designed to surround all the tappet guides. The holes shown were large enough to pass the portions of the tappets which project into the crankcase, but small enough to be covered by
the flanges on the guides. A drainpipe is fitted to one side of the tray, and a, second tray catches the lubricant which is thrown up by the tappets, and drains down this pipe. The oil thus saved can be used for lubricating other parts of the chassis and, therefore, none is wasted.
."1-1.W.C.," of Tottenham, London, has had a little trouble with the fan bracket on his Dennis lorry. This had a habit, when the lorry was running, of slipping down on its pillar, allowing the belt to become slack, with the result that it ceased to drive the fan. Be made a special U-shaped bracket, as shown in the sketch. The legs of the U were secured to the sliding part °Nibs bracket, whilst the crossbar went over the top of the-pillar, clearing it by a small amount. A setscrew in the bar, with lock-nut, retained the bracket in any position, and provided for a little necessary adjustment. H.H.," of Highgate, London, is of opinion that manufacturers of commercial vehicle chassis are very remiss in, that, although they make ample provision in most cases for the proper protection of all the moving parts of the vehicle against the ingress of dust, dirt, and moisture, they leave the ve7y heart of the engine entirely unprotected. He then goes on to point out that the engine takes in dirt with every breath -which it draws through the carburetter, which rather goes to show that he was really thinking of the lungs of the chassis when he said heart. However, no matter ; his meaning is quite plain.
He suggests alternative methods of effecting a cure. The simple one is merely to make a sheet-metal cone, to fit round the carburetter inlet pipe, covering the outer and larger end of the cone with fairly fine gauze. The other idea is a more elaborate one, and involves certain complications in use, which are, in our opinion, sufficient to condemn it from the practical point of view. It is clear from his letter, too, that he has not tried this device himself, and is mainly theorizing. 'He fits a cylindrical pot round the end of the inlet pipe to the carlluretter, with its lower, and otherwise open, end covered with Coarse gauze. A larger pot, and deeper, is placed round this, and filled with water up to a level somewhat above the bottom of the inner pot. The carburetter is thus compelled to draw its air through the water and gauze. The idea is not new, of course, as air cleaners of this type are regularly employed on agricultural tractors. Much of this correspondent's letter is left out, as the precautions he suggests have proved unnecessary.
" E.L.," of Burnley, sends a couple of useful tips concerning the rubber hose connections for water-pipes. New rubber tubing is frequently a tight fit on the pipes; indeed, it is better that it should be. The driver often finds a difficulty in getting it on. In such circumstances a little soap, softened in water, makes an excellent lubricant.
Where water connections are exposed the fasteners, if of steel, frequently rust, and are either difficult or impossible to replace. Even if of brass, they suffer only too frequently from stripped threads, The best and simplest type of fastener can be made by any driver from a length of copper wire. The most convenient thickness of wire is about an eighth of an inch; it should be lapped twice round the hose, as shown in the sketch, and gently tapped all round with a hammer to make sure that it is bearing evenly on the hose. The ends may then be twisted as shown.
The same correspondent sends a suggestion concerning the rejoining of roller chains. His idea is amply illustrated by the accompanying :ketch.