IDEAS ABOUT IGNITION.
Page 33
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Some Instructive Contributions from Our Driver and Mechanic Readers.
THE suggestion of " W.G.W.," of Pimlico, which refers to a simple means of cleaning an oiled-up sparking plug without removing it fr i om the cylinder s of general interest, and on account of the usefulness of the idea, we are awarding him the 15s. prize. IC should first be stated that it is mainly applicable to the special circumstances in which an. engine is known to have leaking piston rings or to be otherwise in such a state of disrepair that oiling up of its plugs is to be expected fairly frequently. The conditions under which it. is employed, too, are presumed to be such that the delay wItich would be caused by taking the engine down, and removing the seat, of the trouble, is one which cannot for the moment be considered or entertained. We will give the remainder of the letter in the words of the writer :—
" From a spare plug take the porcelain insulator, hand it to the china merchant, and get him to drill it, as shown in the
sketch, the hole being just large enough to accommodate an ordinary steel knitting needle. Procure such a needle, and break off, a length of about 6 ins., and about 1 in, from one end heat to redness, so as to soften it, and hammer it gently, at that place, with a light hammer, so as to flatten it.
'Pass the needle up through the hole in the insulator, from the bottom end: the thickened part will prevent its going too far, and will, as a matter of fact, serve Lo locate it longitudinally. Replace the electrode in the plug, and fit the needle with a light spring and wooden knob or handle, as shown. Arrange the electrode so that the needle, when depressed, pierces the gap between the two electrodes: then replace the plug. It should now be clear that, whenever the plug is oiled up, the burnt lubricant may be removed by depression of the needle. It is most essential that the needle be a good fit in the porcelain." The conversion of a magneto for use as a lighting dynamo would not appear, -at first sight, to be a job easily within the capabilities of the ordinary commercialmotor driver. Yet " HAM.," of Rotherham, tells us that he has done it; at a total expense, for the complete outfit, of not more than 17s. He commenced by the purchase of an M.-L. magneto at a cost of 12s. 3d. He removed the armature and stripped it of its wiudiugs, replacing them by one of 20s-gauge wire, a quarter of a pound being smilicient, at a cost of 1s. 3d. One end of this new winding was soldered to the brass collector ring at one end of the armature core, the other to the opposite end of the core itself. The armature was then replaced, as before.
The drive of this new equipment was taken from the fan pulley, and the size of the pulley on the dynamo was determined by experimenting with wooden pulleys. In the end it was found that a speed of 1,500 revolutions per minute, with the engine running at a rate which was equivalent to 12 miles per hour by the wagon, was most satisfactory, and a proper pulley was then turned.
The wiring was simplicity itself. From the hot. terminal on the magneto a wire was run to the lamp holder, another connected the other terminal on the lamp to the body of the magneto, which was so mounted on the engine as to be insulated therefrom. The light is most. satisfactory, being, too, much less trouble than an acetylene one, besides being cheaper.
It, must really be admitted that " H.H.," of Highgate, showed himself to be a man of resource on a recent occasion, when, on being called out to a lorry which was stopped with magneto trouble, and taking a new magneto with him, he found, on arrival, that the driving coupling on tbo magneto he had with him was
not of the same type as that already on the lorry. The one on the spare magneto had a circular flange, with a couple of drilled helps, opposite to one another, in that Range, as shown in the sketch.
Without more ado' " H.II." cut a piece of thin sheet brass to the shape shown in the sketch. He marked the end of the driving shaft with a, couple of 'centre pops, so that, when the plate was screwed into place, the burrs raised by the centre punch would help to hold it, and then, having secured the plate in place, he bent the ends over so that they engaged the holes in the driving flange. On a second and similar occasion, when the driving coupling was of the toothed type, as shown in the second figure of the sketch, a similar expedient was employed, with equal satisfaction, the ends of the brass sheet being twisted over, this time, so as to engage with the teeth of the coupling.
"PD.," of Macclesfield, also took out a magneto to a lorry which was suffering from ignition trouble, and on arrival found that the part. he had was quite
different from that on the chassis which was in trouble. In his ease the difficulty was not one of drive, hot of size, the spare magneto being much larger than the other.
He looked around,-he tells us, until he found a fence from which h0 could get about 18 ins, of wire. Knocking out the hinge pin of one part. of the strap, he threaded the .wire through the hole thus vacated, and carried it over the top of the magneto as shown in the, sketch. The free ends of the wire were then twisted round an old spring washer, and an attempt was made to use the combined wire and washer, as described, as part of a strap, putting the bolt of the part of the strap still in place through the spring washer. This would not, do, because it was found that the wing nut on the strap could not be screwed up on account of its fouling the ends of the wire. This last, difficulty was surmounted by using an old nut as a distance-piece