Call our Sales Team on 0208 912 2120


17th August 1920, Page 24
17th August 1920
Page 24
Page 25
Page 26
Page 24, 17th August 1920 — • FORD VAN POINTERS.
Noticed an error?
If you've noticed an error in this article please click here to report it so we can fix it.

Which of the following most accurately describes the problem?

By R. T. Nicholson (Author of "The Book of the Ford ").

WHAT ARE THE points that make for easy starting on a Ford? It is-clear that there must be something, for, even in warm weather, Fords differ a, great deal as regards readiness in.starting. Sonic Ford engines start at almost the first turn of the starting handle, or at the first turn of the flywheel, when run by the power-starter others—even in summer—call for quite a lot Of


243.—Easy Starting.

I was much struck by the ease with which a Ford can start when a garage owner recently boasted that he would get his Ford to start from cold on the first pull. It seemed too good to be true: but-it-proved to be true, nevertheless. The engine started—by hand—almost at a touch.. It was Just pulled very smartly over once—not swung—and off it went.

Now, I will not promise' that every Ford can be made to start as easily as,that ; but I will promise that, if attention he given to various points in the ignition circuit—points which I am about to name— it. will start very ,easily--almost as easily as an engine fired by a, standard'higletension,magneto. First, let me say that not in one case in a hundred have the magnets anythingito do with. easy or difficult starting. Many drivers have a notion that the magnets get weak.-iand.will not; when so weak, give a strong enough current-for an easy start. Now, it is quite possible for magnets to get weak, but it is utterly unlikely that they will ever do so. The only thing likely to weaken the• magnets at all considerably is running a battery current through them. That is fatal to the magnets. •

On the, old style Ford, there was no battery, so that, on that, there is no danger of demagnetizing • from battery current. On the latest -m od el

Riaeng " Ford there is a field battery "on tap," and; if the

current is sent. through • the magnets by accident, there will will be grave trouble, so take particularly good care to keep the battery connections dear of the magnets.

244.—Magneto Adjustment.

But what-does matter is the adjustment of the magnets in ,relation to the ring of stator coils. You know that the magnets-16 of them

—a r e rigidly fixed to the flywheel, and revolve with it (Fig. 161). As they spin round, they pess very 4; close to—almost touching—the 16 stator coils, which remain still as the magnets pass by them (Fig. 162). The distance between magnets and,stator coils must be not more than 1-32 inch. Indeed, it would be electrically B30 better if the distance could be less than that—such that the magnets would all but touch the stator coils. About 1-:32 inch is however, as near as it is safe to go, for there is always a tendency for some shake to arise in the flywheel bearings, particularly when a Ford gets old and worn, and it would never do-, of course, for the magnets to hit the coils as they will do when there is a bad shake.

For easy. starting, the first point to see to is that the magnets are properly set in regard to the stator coils. This setting is rather a job for the garage man than for you; but it is remarkable that a good many, garage hands d o not know how important this setting is. When you next have to get your engine taken down, tell the garage man that you want the clearance to be 1-32 inch only.

Fig. 162.—The 16 stator coils of the magneto are stationary, and are energized by the passing before them of the rotating magnets.

245.—ABit of Electrical Theory.

• You will see clearly why this, setting is important if you master a little bit of electrical theory.

-Between•the two poles (or ends) of a magnet, .there are ",lines of force." If you took one of the FOrd magnets, and turned it upside down under a sheet of paper and then scattered iron filings on the paper, they would, when shaken, arrange themselves in a certain well-defined manner. These iron filings with their curves and straight lines show that there are-" lines of force" tending to arrange the filings in a certain way.

-Now, if you, pass an electrical conductor through the " lines of force," you can get an electrical cur ,,-rent in the conductor. You touch the stronge t current if you cut straight through the lines of force, and between the-poles (or ends) as shown in Fig. 163. The ordinary t-high-tension Imagneto works by cutting the lines of force between the poles.

The Ford stator coils (or conductors) cut the lines of force just outside the poles, that is, the magnets pass by the stator coils, leaving the stator coils outside and alongside. (The lines of force are cut just the same whether the magnet moves or the conductor moves': it is a question of relative motion.) Now, theolinesofeforce alongside the magnets are comparatively weak.and comparatively few : most of the lines of force lie between the poles. So you can get very littleelectrical-, energy unless you carry the magnets very close indeed to the conductor. Hence, the' need of having the .clearance as small as 1-32 inch. If you had a clearance of as much, say, as half an inch; I doubt whether you would get an electrical current at all.

As it is, the electrical current produced in the Ford magneto by a single magnet passing any one stator coil is quite small. There are, however, 16 magnets—all connected—and 16 stator coils—also all

connected—so that the total output is quite respectable.

The ordinary high-tension magneto has only one or two magnets, sometimes only one, but the armature (or conductor) cuts the lines of force between the poles, and direct, so that a strong current can be very readily produced with a very small machine.

246.—Insulation of Stator Coils.

Then, if is important that the stator coils should be individually insulated, and insulated as a whole. There is a strong tendency on the part of the insu • lation to perish in time. (It is shellac varnish.) If the stator coils are short circuited, you get reduction of voltage. , The more coils that are short circuited, the less the voltage.

Any reduction of voltage means hard starting.

• Often, it will be found that, once the engine has been started, it will run perfectly well, even though it was " the dickens" to start. This may more than likely be due to short circuiting of some of the..stator coils. In such a case, the voltage rises when the engine is running at a good "bats" but is quite poor when it is running only slowly, for instance, when turned over by' hand, or even by the power-starter ; or, if an engine will start perfectly easily on a battery, but only with difficulty, or not start at all on the magneto, 'Suspect the stator coils.

The Ford magneto, even if the stator coils are in bad condition, will give plenty of current for ignition, once the engine gets into its stride—far,more than enough. A Ford engine can be made to run on as little as 4-5 volts, and any old magneto will give more current than that once the engine is speeding up. On the other hand, with the stator coils in bad order, it is quite possible that_you will not be able to get 4-5 volts, when rotating the crankshaft by means of the starting handle.

The Effect of Benzole.

Benzole, as we know, is a solvent of varnishes. The insulation of the stator coils is a shellac varnish. I suspect that some benzole—not much, but some—finds its way past the piston rings into the base-chamber oil, and then attacks the stator coils.

I was recently told—and I quite believe the state ment—that analysis of the base-chamber oil on a Ford that had been run for two years exclusively on benzole, showed two per cell:, of benzole in the oil, and two per cent, might quite well have an effect -on the insulating varnish ; at all events, the stator coil insulation of the Ford in question proved to be very

bad. • I hate to throw this suspicion on benzoic for use in the Ford, because, in other respects, I regard it as a, perfect fuel. If you use it " neat," be sure that you keep the carburetter adjustment as fine as possible, and make it a point to scavenge out your base-chamber oil pretty often. Further, do not leave your engine standing for any length of time unused,. with old oil in the base-chamber, because there is then 'more liability for the benzole to separate out and so to attack the insulating varnish more strongly.

247.—The Magneto Terminal Must be Clean.

This should be kept clean for easy starting. The point is not of special importance, but it still is of importance. Lodgment of foreign matter under the magneto terminal will interrupt—or partly interrupt —delivery of current ; and there is a good deal of foreign matter thrown off by the transmission and brake bands. The terminal 13 easily removed and cleaned. It is shown in Fig. 161:

248.—Adjusting the Tremblers.

The adjustment of the tremblers on the four coils in the box should be as light as possible. The adjuSting screw should be turned up on each unit till the engine just becomes uncertain in its firing. It should then be turned down for a quarter—or not more than half—turn, and then locked by the locknut.

A good many drivers pay no attenticrn to the locking of the adjustment nut. It must be locked, or the action of the vibrator will be uncertain as regards starting. Once the engine has started, almost any old adjustment will certainly keep, it firing, if only it is heavy enough, that is, if the adjustment is turned down far enough. But, for easy starting, you must have a light adjustment; moreover, a heavy adjustment is' in any case; bad for the coil .points because it eats up the points by arcing--bright sparking—there. The potnts then get ragged and you will never get easy starting with ragged points. The gap between the points on a coil ought to be less than 1-32 inch when the spring. is held down.. Never try to adjugt a coil unit in any other way • than by taking up the thumbscr ew attachment. Bending the springs is specially m i schievous. Their tension is made "Just so " by t h e manufacturers. The ,springs do not weaken in use. For easy starting, then, t h e. coil points -Must be set as lightly as possible, and they must .be well trimmed, so asto meet flat and square, though, unless they are badly fitted, the seating of the adjustmentis of far more importance, so far as easy starting is concerned, than the flatness and squareness of the contacts.

249.—Condition of the Timer.

This is very important indeed. Outside, the timer should be wiped over quite often with a patrolled rag. Filth is apt to collect under the timer cover— out of sight out of mind I and can do much mischief there as regards easy starting. Any " muck " on the timer case creates partial shorts of the lowtension current, and makes for hard starting.

Inside, too, the-timer ought to be clean. Here, again, it is not easy to keep it clean. You must oil it, and oil always collects filth. But, there is no reason why you should not often wash it out with paraffin or petrol, afterwards replacing the lubricating oil. Truth to -tell, a dry timer gives easier starting than, one that is full of oil—even if it is clear oil.

There are extravagant drivers who refuse to oil their timers because they say they get easier starting if they do-not. So.they do ; but they also have 'to buy a lot of timers; and timers cost money. But it is not a bad tip to wash the timer. out with paraffin (squirted in through the lubricator), start up, and then give the proper dose of oil. . Now, I do not think that, as regards easy starting, the condition of the fabric inside the timer makes any difference—that is to say, a worn " bumpy " timer, if sound, gives as easy starting, in my experience, as a brand-new one. It is only at speed that a worn timer works mischief. At starting, you get a good enough contact whether the timer is worn or not at the contacts.

But what does make a great deal of difference to easy starting is the strength of‘ the timer roller spring. If this gets very weak, starting .becomes very difficult, especially' if the timer is dirty inside, for it then becomes impossible for the roller to press itself through the filth so as to reach the metal of the instrument. I strongly recommend that this spring should be replaced onces in before it breaks; or, if a coil is taken off this spring, and the spring is then replaced, that will do nearly as well.

250.—The Bearing of Oil on Starting.

In summer weather, it does not greatly matter what oil is used, so far as easy starting is concerned. In winter' it matters a great deal. Now is the time to get your ignition right for easy starting, because if you cannot start right now, it is quite certain that, when the cold spell comes round, you will have no end of trouble. Take time—and your starting handle—by the forelock! Every Ford ought to be made to start in certainly not more than' three easy pulls at this time of the year. Very expert adjustment will get things even better than that ; but I do not grumble if I can start the engine on the third pull.

Hand-starting and a Power Starter.

I have written mainly for the benefit of the handstarter user, but all that I have said holds good just aOmuch for the power-starting Ford. Anything that makes it difficult to start by hand makes it difficult for the power-starter to act. Because the power-starter cannot feel there is no reason why your should not feel for it. Cultivate sympathy for your mechanism—that is the hall-mark of the good driver.

Sparking Plug Points.

Finally, the setting of the sparking plug points must be just so. The proper gap on the Ford is 1-32 inch. (You will see that 1-32 itch is always turning up.) On most cars the gap is greater, but 1-321inch is right on a Ford: with a smaller gap the points oil-and soot up too often. And keep the points clean!


People: R. T. Nicholson

comments powered by Disqus