FORD VAN POINTERS.
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By R. T. Nicholson (Author of "The Book of the Ford '')
recently recommended the fitting of a main fuse to the Ford for prevention of fire risks. ThS form of fuse I destribed gives full protection in the event of battery shorts arising in the absence of any attendant.
I have been asked, however, if it is not possible to provide a fuse for prevention of lamp trouble which arises in case of an interruption of the circuit between battery and ammeter ; because, if an interruption (by breakage of wire) does so arise there, the generator sends its current direct to the bulbs, arid they burn out at once, if switched on.
485.—More About a Fuse.
It is perfectly simple to "rig up " such a fuse. It should be a 7-amp. fuse, placed between ammeter and dashboard switch—that is, in the wire leading from the one to the other. Then, in the event of an interruption between battery and ammeter, the generator current will try to traverse the wire in question, and will promptly melt the fuse out, as generator current at normal speeds has an amperage of 10-12, which the fuse will not be. able to resist (any more than the bulbs could do so). The fuse will, therefore, melt. Now, as fuse wire is cheap, and as bulbs cost money, it ' may be thought worth while to provide this additional safeguard.
The 7-amp. fuse will, of course, carry the lighting current when everything is in order, because the lighting current amperage never rises so high as 7. (I refer, of course, only to battery lighting current.)
486.—The Method of Substitution.
When you are in electrical trouble, what do you do I Different men have different ways of meeting emergencies. There are those who simply "mess about" till they, more or less accidentally, get to the root of the trouble : there are those who reason things out from start to finish, verifying and testing everything concerned ; and there are those who compromise between the two methods—the " sloppy " and the meticulous (" meticulous" being a fearful word which I particularly hate, but you know what I mean ; and I will not use it again—if I remember my promise !).
On the whole, practical men follow the method of compromise, and that method is generally the method of substitulion. Let me explain.
When a light goes out, the obvious method is to substitute a new bulb for the old one. That method does not always work, but it generally does.
When a cylinder misfires, the first thing to do is either to shuffle the coil units, or to try the effect of a good plug in the faulty cylinder. Substitution again. This principle may usefully be carried much farther than it generally is. For instance, if you get an intermittent short which you find it difficult to trace to its cause, you may try the effect of substituting a new timer (cover, or rotor, or both), or of connecting up one or more new wires till the trouble disappears, substituting first the old wires that look doubtful.
The underlying idea of the method is this. Get as good an idea as you can—by inspection—of what causes the trouble, then test for possible faults by the use of good components, whether coil-unit, wire, 'bulb, timer or what not.
'Unfortunately, this method is not always available. For instance, you can rarely substitute a sound battery for one that behaves suspiciously, and you certainly cannot " hoik " out the magneto and put a new one in. (Is that how you spell hoik " 7) But even when battery or magneto is suspect, you can do something on the lines of the method of substitution ; for if the battery falters you can try what the magneto will do, and vice-versa. If one source of ignition
current will work, and the other will not, you know that it is one of them—not the other—that is wrong. That looks like as good common-sense a5. you are likely to get in this world. You., must. however, remember that there are attachments to battery and magneto which may be at the bottom of the trouble, whilst battery and naagnetosthemselves may be perfectly all right. For instance, if there is a break in the yellow wire running from the footswitch, the battery will not provide ignition current, even though the battery itself is all right. Therefore, if your engine would run on .magneto and not on battery, you would not be justified in jumping to the conclusion, "The battery is dead." Your method of substitutions should only tell you that the battery system is somehow dead.
When you are next in trouble, think a bit about this " method of substitution." In nine cases out of ten it will suggest the cure. It is the method of the garage mechanic. He does not argue from A to Z, but looks for the weak spots, and then sees what happens if he substitutes good components, and so cuts them out. In the case of the Ford, it is wise to look to coils, plugs, and timer in case of the ignition, and the bulbs, in case of the lighting. Then substitute there.