Alternator (2 articles)
Alternator tricks1. Have you renewed the brushes? Checked the diodes? I had another alternator that slowly deteriorated until it just couldn't make up enough juice at any speed. The brushes had worn short. New brushes did the trick. If any diodes are popped, change them. Best thing is to find one of the commercial shops that does all the rebuilding work (I used one in Omaha while I was there). Cheaper.
2. At what RPM's does the battery voltage seem to stabilize?
I find, in my 907-powered and Chrysler-alternatored Elite 503, that it takes around 1,200 rpm's to keep the battery from sinking That's with the headlamps lit, as I keep them on for safety (to be seen, like the motorcycles, and Canadian running lights). I have not yet check the condition of this alternator. It works.
3. Last resort... change the pulley to a *slightly* smaller one. If you know your alternator is already in tip-top shape, then try one just enough smaller to raise the alternator rpm's enough to balance the electrical budget at idle. Aluminum pulleys save weight, and free some torque, but you'll pay a bunch more. Try a cheap steel one first.
4. OK, here's another trick... a "commuter" switch and an extra throttle-jack solenoid. Throw the switch, and the solenoid jacks the throttle plates open just a tad -- to raise the idle to a fast idle. And, with a cutout switch on the clutch pedal assembly, depressing the clutch could open the circuit, letting the jack back off the idle. For mine I'll use a three-position switch (Off, On, Always on) and then I can override the clutch cut-out if I want to ride the clutch. Have fun!
Heavy duty alternator
QThe alternator on my 907 Eclat was a Motorola unit. ... Is there a unit that is interchangable and more than 60 amps that I can find in a regular parts store in the US?
A(1)The Elite/Eclat/etc. cars with A/C used a MOPAR unit (Chrysler/Dodge/Plymouth). The unit on my 1972 Dodge Dart "slant 6" (with A/C) looks like a twin to the one hanging on my 1976 Elite 503 -- a 907 with A/C. This was the "heavy duty" one, and they'll easily put out 70 amps or more... Just the thing to light your rallye lamps!
Also make sure you use a 3-terminal solid-state MOPAR regulator. I recently replaced the original one with a good quality Borg-Warner (R-296-P) from Pep Boys. NAPA carries a premium line, too. I've found that the "bargain" regulators don't always do such a good job. The original regulator oscillated, making the lights seem to flicker just perceptibly around 2 or 3 cycles/second.
I noticed that the pulley diameter is about the same, so the alternator spins a bit faster on a 907 than a /6. That starts it charging at a good idle.
There are some more "modern" alternators, but heavy duty MOPAR units are more plentiful, and you can scrounge them on the cheap -- Colin would be proud. After all, he picked it!
A(2)I just had a similar problem with the alternator on my Europa TC. You should be able to get similar replacement from an alternator rebuild place. The Europa had a US Motorola that the dreaded previous owner must have put in. I tried looking through the stock of a very friendly parts store, without any luck of finding one that was easy to fit. The parts store refered me to a place around the corner that supplied them with rebuilt alternators.
I went to the rebuilder and he told me that the Motorola alternator operation had changed hands. I think he said Prestolite, but I am not sure. Parts for the Motorola units are readily available and they are popular in industrial and marine applications. It was not cheap at $160 US, but it was a bolt up replacement. He did include a new voltage regulator that attached to the back of the alternator. Not integral like the newer Delcos, but a better package than the remote voltage regulator that I had. The rated current was 55 amps just like the old one. There are probably bigger ones that would fit.
The alternator on the Europa has the 180 degree flanges, although there are 3 choices on one side. Given the stock that this rebuilder had, the style you mentioned should be available.
I had also considered replacing with a Delco, but I would have had to gone to a machine shop to have a new mounting bracket made. The cost of the bracket and the added hassle made the exact replacement more attractive.
There is some info on alternator conversion here
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