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Waiting for the UPS truck in Tullahoma, TN

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Posted 10 November 2014 - 10:48 AM

As previously reported, the Model A's generator gave up the ghost on the way to Mt. Juliet, TN.


Yesterday morning, while I was posting my trip report, my friend Bill Brigg's removed the generator from the car, which he kindly housed in a garage stall in his basement workshop.




I was suspicious of the brushes but on inspection they seemed fine. All three of them were riding on the commutator properly and the brush springs were free and operating as designed. The only thing we noticed was a badly deteriorated wire connection to one of the brushes; a number of the strands in the wire were parted and all of the insulation was gone. And the whole thing was covered in green corrosion.


As the only visible problem we could find, we made up a new brush wire using a couple of crimp-on eyelets and some flexible copper wire from Bill's parts stash and installed it in place of the deteriorated brush lead. You can just see the bright new copper link in the picture below.




Here's Bill reinstalling the generator in the car.




Unfortunately, when we fired up the engine to see if we had fixed the problem, there was no improvement: the generator was still not charging.


One of the experts at the Ford Barn's Model A subforum advised me how to bypass the cutout and the ammeter to eliminate them as the source of the no charge problem, so we performed both of those tests. Bypassing the cut-out (which is done simply by connecting a jumper wire between the cutout's input and output connections) resulted in an indication of discharge on the ammeter. Bypassing the ammeter gave the totally zero gauge reading one would expect.


My conclusion is that there's probably been an insulation failure in the generator, either in the armature itself or in the field coil windings, and that's not unexpected due to the age of the unit and the extreme conditions it has been forced to endure on this long trip. When these cars were new, it would have been very unusual for a Model A to travel nearly 2,500 miles at 40-50 MPH speeds; the roads of the time were such that it would be hard to run so far at such speeds.


After much consideration, and some checking to see if a generator was available in the Nashville area for purchase or loan, we decided to head for Tullahoma on the battery alone. This was not much of a risk, as the ignition system draws so little current from the battery it would take several days to pull it down to the point that car won't run. The big users of battery power are the headlamps and the starter, and if we avoided using those, there should be no problem, and there wasn't. We arrived in Tullahoma at about 4:15, a hour or so before it would be dark enough to require headlamps.


During the run down to Tullahoma, the ever-concerned Joe Wylie gave me another call to see how we were doing. I reported the generator problem and inquired whether it would be possible for Bert's to overnight me a rebuilt generator on Monday, even though they are closed on Sundays and Mondays. Joe said he'd go grab one from the store and ship it out from the ice-maker company where he works. But when he called Steve, the owner of Bert's, to let him know what he was going to do, Steve said he'd just go down to the store and ship it from there himself.


I can't say enough about the people at Bert's - they have bent over backwards to assist me in my crazy trip. It's the kind of customer service that's almost extinct these days. And they're operating on the honor system with me, as they didn't feel it necessary to take my credit card number and in fact, we've still not settled the invoice for the parts Joe installed on the car when we stayed in Denver over the weekend to let him go through the brakes and chassis. Does it surprise anyone that Bert's Model A Center gets my highest recommendation as the place to patronize for Ford Model A parts?


In talking to Joe, he advised going with one of the new 6v positive ground alternators that are now available for Model As. They're lighter, more efficient, much more reliable than even a well-rebuilt original generator, and contain a modern internal voltage regulator, eliminating the crude original cutout regulating scheme. There are reliable cutouts now available that use a modern diode arrangement internally, rather than what is essentially a relay, but they're a little pricey ($50 or so) so not having to purchase one of those represents a savings as well. An additional plus for the alternator Bert's supplies is that it is a new unit, not rebuilt, and there is no core charge nor a need to ship a heavy core back to them.


Since my usage for the car will be local runs and tours with various old car groups, the alternator just made the most sense. Because the car is not to be a show car, the "un-originality" of an alternator is not a concern. So an alternator is what UPS will be delivering to us tomorrow morning (hopefully by 10:30 AM, as is supposed to be the case with Red Label service, and if they do, we should be able to install it and get home tomorrow afternoon).


The run to Tullahoma also was troubled by the return of engine misfiring and bucking, which I am virtually certain is due to the ignition points. This happened earlier in the trip and resetting the ignition point gap cured it completely. The car was running so well when I picked it up that I didn't bother to install the new points I brought in my spares kit, but we are going to do so today. Even with a new lubed distributor cam installed before we left Oregon, the decades-old rubbing block continues to wear and the surfaces of the points themselves are now so jagged they won't set correctly with a feeler gauge. So while we're awaiting the alternator, we're going to install the new points, condenser, and ignition coil I have with me, do another full greasing, and change the oil for the third time.


After that, I think we'll visit the George Dickel distillery for their tour. The Jack Daniels distillery is fairly close by (12 miles) but Geoff and I have both toured it more than once and we've never done the Dickel tour. Will also spend some time just driving around Tullahoma, as it was where I was born and where I lived until age 12. As might be imagined, it has changed enormously in the past 48 years...

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