Alternator Failure

R

rfitzpatrick

Well-known member
After my generator failed, I've since, gone thru two more alternator fails-- owned the A since 2018. and driven weekly. Don't seem normal -- suggestions I should consider, please
 
As Jim says. In addition, never EVER run the engine with the battery unhooked for any reason. Disconnecting a battery cable or the output wire from the alternator with the engine running can destroy the alternator rectifier or internal regulator.
 
A properly restored original generator will provide many years of trouble-free service. The problem is few people bother to restore them properly. Most just do a patch job or bubba repair. It takes time (I typically spend about 8 hours restoring a long type model A generator. 12-15 hours on a Powerhouse), correct parts, special tools and experience to restore them right. Alternators have several advantages, technology marches on. But reliability is not one of them.
 
Good ground plane was already mentioned. The charging circuit through the amp meter should also be tested through and checked for any loose connections.

A lot of hobby vehicles aren't driven enough to maintain a good battery condition and state of charge. A weak battery can cause charging system problems due to the stress on whatever does the charging. A 6-volt system is a minimal function system which makes it vulnerable to problems. This was the main reason for the change to 12-volts in 1956. Folks wanted more and more electrical accessories as they became available and 6-volt systems were already taxed to the limit.
 
Katy: First was rebuilt/repaired - so later failed again, was told an internal electrical failure. So I bought a second one, couple years later, and this month it failed. Today I directly grounded my second, no change. When I attempt to blow the horn, I do get an ammeter discharge. Now can an alternator repairman determine -- by inspection mine - what caused failure? Thanks
 
Possible you have a somewhat severe intermittent short somewhere in your electrical system, causing damage to the charging circuit. This is especially true with alternators. In an unprotected electrical system like a Model A with no fuses or circuit breakers, alternators can become the "default" fuse which bears the load of a short. This can cause internal electronic components in the alternator to "fry". I had this happen in more than one instance with customer cars.

When we have issues with a generator "going bad", we naturally believe a modern alternator will "fix things" and give better reliability. This can certainly be true ................... if the whole of the other circuitry in the car is in equally good condition as that new alternator. Remember, though, that our cars were not designed for alternators, so merely making the upgrade to an alternator may not be the ultimate solution if the rest of the system could be prone to problems.
 
I prefer original parts like generators, just keep a spare one ready to go. When I was a kid in the late 1960s the Model A Club took a trip to Death Valley CA. Which was a long way from home in a Model A. Somebody lost a generator in the desert on the way there. There were no cell phones back then. They got out the membership book and found a guy living in the desert and they drove to his house. He provided a generator, and the club was on its way gain. Looking back somebody should have had a spare generator for the trip. A couple years later they made the trip to Death Valley again. One of the Model A's hit a wild burro and smashed the radiator back into the fan. You can't carry every part you might need.

I was mechanic for 30-years. It is unusual to lose two rebuilt alternators, even if they are rebuilt. I would look at the wiring and make sure its correct. I've seen rebuilt alternators from stores with only one new brush, and one almost worn out. They were rebuilt just enough to make them charge so they could sell them. It got to the point we were only installing "new" alternators and starters at work. It just wasn't worth it. It was at the phone company, so we had unlimited funds. I still used to take the old ones apart to see what went wrong with them. I would take your alternator a part and take an ohm meter/ voltmeter and diagnose what's wrong with it, or what's wrong with the cars wiring.
 
Did you charge the battery with the battery cables attached? If so, again without fusing in the system, a surge somewhere in your electrical/wiring system could go strait to the alternator and cause the problem.
 
nkaminar said:
Yes, you cannot carry every spare part, especially a spare burro.
Click to expand...

Now Neil, I tend to differ with that statement. I have seen just the opposite where guys seemingly have every available area crammed full of every part imaginable just to make a trip across town. :D



With regard to the alternator failure discussion, most are using the GM 10Si Alternator that was last installed by the OEM in the early 1970s. That was over 50 years ago, ...and while these same units are now being manufactured in China, I am not sure what kind of life expectancy one should expect out of these units, but I do know the failure rate on these units is very high because no one supplies good quality replacement parts for them.

As for a little history on these, ...I can remember as a teenage kid that club members were installing these units to replace failing stock generators because no one was manufacturing a replacement armature, nor good quality brushes and coils. Even Cutouts back then sucked. Now 50 years later, all of that is different. Other than supplying power for an electrical system on a Model-A that has an Air Conditioner installed, there honestly is not any valid reason to convert to an alternator, nor use anything other than a 6v battery. If there is one, I would like to hear it.
 
Did you at any time start the car with dead battery using jumper cables and then allow the alternator to charge the battery?


The information listed here is from the Optima battery site listed below:

Fact: Alternators are not designed to charge dead batteries.

"Jumper cables can be a lifesaver, literally! However, when you use jumper cables to start your vehicle, you are placing a tremendous strain on your vehicle's alternator and battery.

That is why we recommend fully charging deeply discharged batteries with a battery charger as soon as possible.

Idling your car in the driveway or taking a drive around the block will not charge your battery or even keep your battery's voltage properly maintained.

We're not alone in that thinking either. Look at the first installation instruction on this alternator box, which is printed in bold text, for additional emphasis- "CHARGE BATTERY - (12.6 Volts min)

The alternator isn't designed to charge a dead battery. Premature alternator failure can occur and may Void Your Warranty."

See this Optima webpage for additional info:

https://www.optimabatteries.com/exp...ors-are-not-designed-to-charge-dead-batteries
 
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According to a rebuilder I have gotten parts from the Delco alternator most used for model A conversion is the best alternator ever made— parts are cheap,easy to rebuild and lasts just long enough that the people aren’t pissed off when it needs replacing again.
The one in my chevy truck has been rebuilt 4 times in 40 years.
My model A generator I just had to replace the front bearing after 50 years and I have used it to charge a total dead battery a couple times.
The last time I repaired my Delco alternator I searched through the rebuilders junk bucket and fixed it with used original delco parts— that seems to have cured the repeat failures so far
 
Kurt in NJ said:
According to a rebuilder I have gotten parts from the Delco alternator most used for model A conversion is the best alternator ever made— parts are cheap,easy to rebuild and lasts just long enough that the people aren’t pissed off when it needs replacing again.
The one in my chevy truck has been rebuilt 4 times in 40 years.
My model A generator I just had to replace the front bearing after 50 years and I have used it to charge a total dead battery a couple times.
The last time I repaired my Delco alternator I searched through the rebuilders junk bucket and fixed it with used original delco parts— that seems to have cured the repeat failures so far
Click to expand...


Kurt, you nailed it. The current importer of the 10Si who is having these manufactured in China is based in the next town over from us. According to an employee, the defect rate is high. But as you stated above, parts are cheap (quality) and lasts just long enough ...to get past the warranty.
 
I totally concur with ndnchfregarding keeping the stock 6v generator. If your wiring is in good condition and you properly maintain your engine, the 6v generator works. Adding a solid state voltage regulator and LED lights improves overall electrical performance and reliability another notch.
 
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