FORD VAN POINTERS.
Page 39
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• By R. T. Nicholson (Author of "The Book of the Ford ").
IN MY eontribuition to the C.M. for May 2nd I set a tittle electrical problem, and invited attempt i at solution. By the Editor's kindness, I was able to offer a prize of half-a-guinea for the solution which, in my judgment, best deserved it.
. 461.—That Little Problem. .
Perhaps I had better. resstate ,the problem briefly: A correspondent had told me that his 1915 Ford would every now and again peter. out while running ;, that he had found that his only way of starting the engine again was to." short, ' across with a screwdriver blade from the magneto terminal to the tranknission cover.
This mystified me, for I could not see what effect this " shorting " would have.
I made various suggestions to my corresisondent as to effecting a permanent cure; for instance, flushing out the crankcase, with the idea of removing any foreign matter' from the stator coils, verifying soundfloss of insulation of magneto terminal post, soundness of magneto cable wire, and tightness of all connections between magneto cable binding post and coil box, and, again, between coil box and switch and at switch.
My correspondent could find nothing wrong at any of these points, except slackness of screws on the magneto side of the switch. 'He tightened these up, and the trouble has not since occurred.
Quite a number of solutions have been sent in in reply to my request and offer. Almost without exception the efforts have shown that Ford drivers have a good grip on the essentials of Ford electricity. My impression is that, as a class, Ford drivers probably know more ofthe " innards " than drivers, of any other kind of motor. This is partly because the Ford responds to " amateur " treatment, partly because it, calls for regular little attentions, and partly because the Ford is 'different."
Evenethe boy of 14, who writes as follows, knows something of his subject: — '1 Alough I am only 14 years of age I get the chance of seeing The Commercial Moto. r regular and take a great interest in motor transport.
"I think the solution to the problem is that some soder connection in the mag. has 'shook loose and when the mag. is shorted the heat that 'is produced is sufficient to fuse the soder again."
That boy ought to make good. It seems that the problem has occurred in practice to a geed many drivers—mainly with old-style (nonstarter) Fords—and that the screwdriver .'method of treatment is by no means unknown.
At first I wondered how on earth anybody thought of the screwdriver tip. I can's however, now see why it was tried. When the engine petered out, it was natural for the driver to want to see whether the magneto was generating. He therefore got somebody to turn the starting-handlewhile he (the driver) "
shorted" the magneto terminal in the way
leseribed. He argued that if he saw sparks at the sontaet points he would know that the magneto was generating all right. He may net have seen the sparks at first, but encouraged his pal at the starting-handle Lo go on turning, in the hope that the sparks would become visible later. When they appeared, he'
s naturally, withdrew his screwdriver blade, and the 2ngine then began to fire.
F.W.P." (Camberwell) had exactly the same trouble with a 1913 Ford, and effected a tenaporary cure in exactly the same way. So, too, had "J.W. ,Victoria), same cure, and E.W.R." (Headingley). yearly all competitors attribute the trouble to foreign matter shorting the stator coils; but they nearly all fail to account for the success of the screwdriver application. Other competitors know that the trouble was permanently cured in their own cases by correcting faulty insulation of some of the stator coils, but the screwdriver touch bothers them. Others, again, trace the trouble to use of wirewoven linings for the bands, or to lubricating with graphifed oils. Looseness or faultiness of the magneto terminal is a favourite theory, and pressure laterally from a screwdriver, might remedy things.
Taking it all :round, the following solution offered by E. W. Revell, 1, Sagar Place; St. Michael's Road, Headingley, Leeds, satisfies me the best:— The Prize Solution.
" Having also resorted to the screwdriver method' of restarting a Ford engine on several occasions with success, I, like your correspondent, am interested as to the reason why the engine peters out and also why a screwdriver used in the way
indicated should prove such a valuable asset. . . My theory . . . is as followss " In my opinion, the engine peters out' owing to two minor troubles occurring at the same time— each one insufficient to cause the engine to stop by .itself, but the two faults operating in conjunction make one big trouble, and the engine strokes.' When t a engine fires perfectly, it by no means follows hat everything is 'as it should be, although good en ugh for the moment. I therefore suggest that the ignition system in question was generally a bit off lour.' Perhaps the timer was not perfectly clean or the, roller not making good contact. The various entacts may not have been as they were in
tended . be. Faulty wiring, incorrectly adjusted coils an plug points, and the latter partially fouled, all Offer undue resistance to the electrical current. Sipco a electrical current only follows the line of least. res stance .ies proportion to that resistance, it can be ken for granted that only a certain proportion f the available current flows through the
nition system, and this, although sufficient to run e engine normally, is insufficient to overcome fur ther resistance. The further resistance ' is in the form of foreign matter coming into contact with the main collector terminal. Thus the engine stops.
" A screwdriver blade, or other good conduetor, if placed across the main terminal to transmission cover. . . . forms an easy path for the current. The output of the magneto is at its best, the windings of the stator become saturated, and when the screwdriver is removed the sudden rush of current starts the engine, the oil splashing around the inside of the transmission cover displaces the foreign matter on the terminal, and all is apparently well till the same troubles co-operate once more." It is true that Mr. Revell does not indicate the switch as being contributory ; but, on the other hand, the switch is one of the points (referred to) where undue resistance could be set up ; so that Mr. Revell may rightly be complimented on his diagnosis.
462.—With Compliments and Thanks.
• I have not referred to the many nice things that have been said about the help that competitors have got from my " Pointers " and books. If I acknowledged them suitably, this page *ould have to be printed in red ink, so deep are my blushes. Seriously, I am glad to know that I have been so helpful. As for my blushes—I cannot help them I •