I think it's time to move to an alternator

[spinelll]

A few weeks ago I noticed a lot of play in my generator. So much so, that the brushes were only partially over the commutator. A buddy lent me another generator and I installed it with my cutout.

Check out the image showing my ammeter readings. Note that when I say "High rev", that's 40mph in 3rd gear.

With lights on, even at a high rev, I'm in the negative. I realize that +10 is high. The only way I get a decent horn is high rev without lights.

I didn't have this issue with my old "wobbly" generator but there's just too much play in it.

I don't think it's worth rebuilding. This ain't a points car.

Leo

[DJ S]

Did you adjust the output brush?

[J Franklin]

Rebuild the generator, it will serve you well.

[Conaway2]

A stock generator in good condition should run lights and horn with no issue. If you upgrade lighting to LED headlights, the electrical system has more than enough power to run everything very well.

Good luck !
Jim

[Kurt in NJ]

The owners instruction book says there will be a discharge showing on the ammeter with the headlights on and running under 10 miles per hour.
The suggested charging rate is 10 amps winter 6 summer ----it has to be adjusted for your use, your daytime charge rate has to make up for your night time discharge rate and the normal losses when the car is sitting.
I got one of them alternators in my chevy truck it has been more of a problem than the generator, have rebuilt the alternator 3 times in 40 years it's used up 4 belts. The generator in the A has only needed charge rate adjustments due to changes of use and minor belt adjustment adjustments ---over 50 years ---

[GeneBob]

Sponsored Links (Register now to hide all advertisements)

I switched to an alternator in my Tudor and have had to adjust the belt numerous times. I never thought much of it but Kurt in NJ made me realize just now that the alternator probably has a higher load on the belt and therefore wears it more?

[nkaminar]

I am very happy with the alternator in my car. At a very low idle I get a negative current flow but otherwise it is always positive or zero when the battery is fully charged, as it should be. My volt meter shows 14 volts when driving (it is a 12 volt system). The battery never gets overcharged or goes flat and the alternator keeps up with any loads placed upon it.

A generator in good shape will provide all the current you need. The problem I have with the stock generator is the need to adjust the current with the third brush. In the past on other cars I have installed a voltage regulator (6 volt type) in a hidden location and used that to control the field windings. That eliminates the need to adjust the third brush for the seasons and the type of driving and eliminates over charging or under charging the battery. The generator with the regulator keeps up with the loads.

[lotsagas4u]

Maybe just me, BUT, a alternator on a model A looks like S###.

[Bob Bidonde]

This may be of use in your choice:

[nkaminar]

You can buy an alternator that looks like a generator, if that is important to you, but they are expensive. Check the back of the magazines or search online.

[antiquepa]

(post 10) I moved to the alternator on both my A's, that look like a generator and am very happy with them. Bright lights and the horn will blow any time. Around $350.00 each
but well worth it, looks original, I did switch to halagon head/tail lights on the one A,and also had to upgrade to a 30 amp gauge. My opinion is money well spent. Looks original!!

[Herb Concord Ca]

Bob what does the black/yellow wire connected to the terminal box do?

[nkaminar]

I will answer for Bob. That wire supplies current to charge the battery. The current runs through the ammeter and then to the post on the starter switch, usually through a aftermarket fuse.

I think that a volt meter is more important than an ammeter. I run both. The volt meter will tell you if your battery is getting weak from age. Just turn on the ignition and look at the voltage. It can also tell you if your starter and cables and starter switch are in good condition. Or if the battery is getting over charged because of some fault with the generator or alternator.

[AL in NY]

I decided to run an alternator because at the time I purchased halogen headlight bulbs with the new Bratton's reflectors for better night vision. I don't like the looks of an alternator on a Model A. Somehow, I found that Russ Evans makes just what I was looking for, an alternator the looks EXACTLY LIKE a Model A generator. Russ Evans is in Simi Valley, California and makes this alternator with the correct cutout included. It's a 45 amp, 6 volt, positive ground unit that will pass fine point judging. It cost about $385.00 (in 2016). Russ stands 100% behind his alternators and will replace any defective units without question. He is a Model A guy and will build the unit for your car, just supply him with your month/year build date and he will make up one exactly as needed for your car. He doesn't have a web site or email, but he can be reached by phone at (805) 428-2564. He also makes a 12 volt, negative ground unit. I bought mine from Russ because I felt better about giving my money to him verse a big corporation. I purchased it in 2011 and have put over 10,000 miles on it without a single problem. The battery is always perfectly charged and I don't have to worry about driving at night. Unfortunately, I don't know if Russ is still making these alternators.

[Synchro909]

IMO, the alternators sold by the vendors are ridiculously too big. 60 amps and 12 volts is several times what you need. 15 amps is enough to run a car with headlights on, ignition and tail lights.
In addition, to get that output and to get them running at high enough revs with a slow revving Model A engine, the alternator pully is very small. That means more frequent adjustment and shorter belt life.
I run 4 of them and I have working generators sitting on a shelf gathering dust.

[rotorwrench]

The 10SI works just fine on 12-volts but the flaw with the 6-volt conversions is that the regulator sets the voltage too high. This can have a negative affect to the battery over time.

[chap52]

I installed a NU-Rex 30 amp 6vt alternator. I found it to be exactly what I needed. Only $215 and didn't seem to offend anyone when I opened the hood. Chap

https://www.nurex.com/alternator-6-volt

[Bob Bidonde]

The alternators in my Model "A's" are 12V 60Amp with self-starting single-wire hookup regulators. Each alternator has a small pulley.



In my opinion, the best features of the alternator are very quick replenishing the battery after starting, it enables the use of very bright halogen headlights and it has enough power to run my heated seat covers.


The GM alternator in my Coupe failed during a Model "A" club run several years ago. Fortunately, there was an Aide's Store nearby, so I traded in the dead alternator for a rebuilt one and it only cost me $24. Within an hour, my Coupe was on the road again.

[spinelll]

Thank you for all of the replies.

I guess my main question is whether the stats listed in the attached image are abnormal for a generator in good shape. If they are abnormal, then what would the numbers be with a "good" generator?

And yes, I did play with the 3rd brush.


Leo

[WHN]

Originally Posted by lotsagas4u

Maybe just me, BUT, a alternator on a model A looks like S###.

Well said. For 92 plus years, a good generator has worked just fine.

The more owners modify their cars, the better for the owners of stock Model A’s. The stock cars just become that much harder to find.

Enjoy.