REPAIRING IGNITION BREAKDOWNS.
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Suggestions in Connection with Magnetos by Our Driver and Mechanic Readers.
THE MAGNETO is usually regarded by the majority of drivers as somewhat of a mystery, but there are many repairs which may be executed without difficulty to the portions which are most likely to cause trotible in the case of an emergency. In the event of the defect being of a complicated nature of course little can be done, and generally the services of a specialist in this class of repair have to be employed.
A broken spring in the make-andbreak is a comparatively likely occurrence, and an emergency repair is suggested by " A.A.M.," of Dulwich, to whom this week's prize of 15s. is awarded.
As a rule the spring in question fractures somewhere about the centre of its
length, and in consequence the arm ceases to function. The first step in the event of such a breakdown is to remove the screw and broken end of the spring attached to the make-and-break plate. The flat spring (2) is next turned so that the arm of the make-and-break may be lifted off its pin, together. with the other portion of the broken spring (5A). The latter spring is pressed down by the fingers until it is almost touching the arm throughout its length, and it is held in this manner until the arm has been replhced. Spring 5A. will now be fixed between the arm and block 1,so that it has a bearing on the latter and will tend to close the gap when the heel of the arm is not on the cam.
WHEN the platinum points of a
magneto make-and-break are worn out, or, in other words, the platinum has entirely disappeared, the magneto will usually cease work and let a driver down rather badly, as, naturally, owing to the high cost of replacement points, spares are rarely carried. "H.A.B.," of Rotherham, describes a repair which he executed in such circumstances, and he states that this repair has proved satisfactory for a distance of 3,000 miles.
One point had completely fused away, and the screw carrying it was removed. The hexagon head, to which the platinum point was fixed, was cleaned and a new point was made out of a small piece of silver, punched out of a shilling, approximately equal in diameter to the original point. With the aid of a small soldering iron, the aforesaid silver point was fixed on to• the pin in a matter of about half an hour.
Since the first occasion on which this scheme was employed, " H.A.B." has repaired two or three other magnetos on similar lines with success.
A LOST carbon brush from the makeand-break caused "SS.," of Blackpool, to devise the following emergency repair. A piece of lead pencil was taken and trimmed down until it was an easy fit in the hole which normally accommodated the carbon brush in question. One end was tapered to a blunt Point and the wood on‘the opposite end was stripped until about 1-16 in. of the -lead was uncovered. A piece of wire was then taken and fixed to the lead and wound to the approximate dimensions
of the missing spring. " S.S." states that this repair enabled him to get home without difficulty.
DRIVERS of Ford vehicles fitted with Blu-Blaze timers have probably found that when the brush becomes worn misfiring and difficult starting are caused. " T.L.," of Byfield, has found that a simple repair is to place the timer horizontally on the bench and file away a small amount of the rim, thus permitting the body of the timer to come closer up to the rotating portion.
The process described may be repeated on several occasions as the brush becomes more and more worn away.
AN oiled-up sparking plug is quite a
common cause of engine stoppage, and the method of curing the trouble employed by " J.T.W.," of Bishop Auckland, will doubtless be of interest to many in this connection.
When the defective plug has been located, the corresponding high-tension lead should be detached from the terminal on the magneto distributor and the engine started up on the remaining cylinders and kept running at a fairly high speed. Holding the detached hightension lead, taking care to grasp only the insulated portion, the naked end of the wire should be held at a short distance from the terminal and the spark jumped across the resulting gap a few times. Providing the points of the sparking plug are not in contact with each other, the current, being intensified by the gap, will probably break down the carbon or oil deposit upon the plug points and rectify matters.
BROKEN carbon-brush holder on a Bosch magneto gave rise to an ingenious repair which "O.P.J.," of Eastbourne, executed when spare parts were not immediately obtainable. The brush holder was broken in half through its centre. As a jointing medium a piece of pitch was taken and softened, and by working it into the fracture it enabled the broken portions to be held together for a period of three days.
Many other ignition defects are traceable to perished or chafed insulation on the high-tension wires. As a rule. there is little slack in the leads, with the result that it is not always possible to cut out a faulty portion and connect up again. Paper wrapped round and fixed in position with string may serve as an emergency repair.
If a vehicle be equipped with acetylene lighting there is generally a considerable length of rubber tubing available for use as an insulating medium.