IDEAS ON SECURING ENGINE EFFICIENCY.
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Miscellaneous Tips which have Proved their Value to Driver and Mechanic Readers.
THERE is one thing which writers of letters for this page should avoid, and that is to tack, on the and of the -letter, Some Pequest to the Editor for -information. Letters for this page are not read through immediately, but only so. far as. is necessary to classify them -according to subject. They are then filed until it is the turn of that par.
• tieular subject to appear again. We are impelled to these remarks by the letter teem " C.F.," of Eastbourne, which was received some months ago and filed away as described above. On reading this letter through, we now find a postscript asking if the device which he describes is worth patenting, and whether it would command a sale.
• Our answer to both questions is, as it so happens, in the negative; but it might just. as well have been the case that -the matter embodied in the postscript was important, and urgent, in which case "G.F." would have been inconvenienced.
. He tells us that he has had from time to time a certain amount, of trouble with valve caps of the type which has four slots cut in a somewhat shallow flange. There are few of our readers, we imagine, who have not, at some time or other, experienced such trouble.
has got over it by the use of an extractor of the type which is illusfrated by one of the accompanying sketches. A casting is made, to fit easily inside the hollow of the cap, and having four lugs or ears whichclosely engage the slots. This casting has a hexagon head, and is firmly secured to the valve CE43 by means of the bolt shown, which passes
right down through the casting and engages the tapped hole for the sparking plug or compression tap. The design may, he points out, need modification to Suit individual needs.
WHILE on the subject of valves and valve caps, it may he of interest to pass on a tip which we have received, from " A.M.D.," of Lanark. It is familiar practice,'is he remarks, to place a light spring under a valve head to lift it from its seat in the intervals of grinding it in. In case a suitable spring be not available, one can readily be made by winding a piece of steel wire in loose
coils on to a bar of i-in. round iron. The wire, so prepared, will be found to retain sufficient 'resilience to enable
• it to carry the weight of the valve and • to lift it clear of its seat when the down-ward pressure of the brace ceases.
'TROUBLE with the timing gear of a, Maudslay necessitated reMoval of the magneto driving wheel, which,, in this case, was in one piece with the starting dog, and keyed to the end of the crank
shaft. In order to facilitate the removal of this part, its flange had been drilled and tapped for the reception of two push-off screws. "R.C.C.," of Great Yarmouth, however, found them useless for the purpose, and all the ingenuity which he brought to bear on the job during a couple of hours proved fruitless.
Eventually he took off a couple of spring clips, which he rigged up in conjunction with two lathe clips, in the manner shown in the sketch, so that the spring clips passed round the aforesaid flange, and then round the lathe clips, which bore on the ends of a piece of flat bar, placed against the crankshaft.
THE use of a chart, which may be mounted on a card and hung up in the workshop, to enable the workman to determine at. a glance the operations in the various cylinders of an engine, is recommended by "G.V.J.," of Taunton. For an.engine in which firing occurs in the order 1, 3, 4, 2, the chart would be as given below.
IN our issue of February 5th we pub.
lished a letter 'front "A.W.R.,'of Canterbury, referring to a most unusual difficulty with a -gearbox, In describing the very unorthOdox repair which -had been effected, we ourselves asked the purpose of an exterior bolt by which -the gearbdx, when repaired,was coupled to the side meMber of the, chassis frame.
"A.W.R." has now replied to our query. Apparently he realized that :without this extra bolt the whole of the stress of holding the broken gearbox ,together Would have had to be borne by a small area of the thin wall of the aluminium gearbox, and ho was, afraid that as this wall had no supporting ribs it would not bear the strain—hence the extension of the bolt as described. The gearbox cover, he tells us, was very .thin, and was only held by 4.-in. screws, so that he felt that no reliance whatever could be placed on this. Incidentally, he remarks that in connection with any such repair as, this he is always inclined to be over-careful.
A FEW useful tips about starting handles are embodied in a letter which we have received from "R.H.," of Trowbridge. Some starting handles, he states, have _wooden sleeves on the handle. Not. infrequently these sleeves split, and. leave the handle bare. As a resAlt of this and similar happenings, the hand of the user is liable occasionally to be scratched, to say the least (often enough the damage . i a nasty gash, rather than a scratch). As a preventive, take a piece of radiator hose, somewhat smaller in internal diameter than the handle, and slip it into plate. It will afford ample protection, besides improving the grip of the handle.
Starting handles are sometimes encountered which are fitted with a release spring which is so powerful that it, is impossible to keep the handle engaged for more than half a turn. In such circumstances it is no crime to fit a new and lighter release spring. A little oil on the spindle of the handle is also a help.
Do not, he says, neglect to have the starting claws recut or renewed When worn. A nasty knock on the dumb-iron or lamp bracket often results from this omission. It is important, too, when having the jaws recut or renewed, 'CO see that they are placed at the right angle to the handle. The compression should be encountered as the handle is being pulled up, and riot at the top or bottom of the stroke.