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Discussion Starter · #1 ·
I started up the 78 Elk again today. The volt meter went to +13 volts, then dropped to the orange line. Is there a part I need to change in the alternator or do I need to change the alternator?
 

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I would get the whole thing and the warranty. If you replace a part I don’t know if they would warranty that electrical part. Then you would have to remove the alternator for your part anyway so the labor is the same. Take the old one with you and some places can test it with a load. Then you have it there to match up and for the core charge.
Tom
 

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Discussion Starter · #4 ·
Since I put an alternator from a V6 Maibu is there any difference between it and the one from the 73 350?
 

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With regard to what to change, it all depends on what are your electrical needs. Nowadays, many classic car enthusiasts add new newfangled goodies, so just stock replacements are not sufficient. I would opt for a new alternator that can provide more amps.
 

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Since I put an alternator from a V6 Maibu is there any difference between it and the one from the 73 350?
Alternator ratings (in Amps) are determined by the vehicle options, not the engine size. The more electrical options (AC, power windows, etc), the bigger the alternator. For the 229 V-6, the mounting brackets are the same, so the physical housing swap back and forth with no problem. Just make sure the amp rating on the replacement matches or exceeds the alternator mounted from the factory.
 

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From what I can find out in 1978 it would either come with a Delcotron 37Amp or 61Amp ( option/standard if you have AC in the car) alternator.
So probably any new one you get will have about 63 amps or better.
My preference is usually AC Delco parts if possible. I would get new.
You can also located a rebuild shop near you and have yours rebuilt.
Also many auto stores are able to bench test your alternator if you take it off and bring it to them.
 

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The electrical system that came with these cars is the 10D.N. It has a very high average current rating with a stand alone voltage regulator. Having the regulator mounted on the radiator support with nice cool air on a steady section of the car is the best..
 

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Is your car stock/original? And we are talking a 78 Elky?
I don't believe you car has an external regulator. I have a 79 service manual and it states that the regulator is built in.
From what I can find out the 10DN type generator/alternator system ended in about 1971/1972. It was GM's first go at an Alternator. It came out in about 1962.
An alternator is just a generator for AC.
 

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The electrical system that came with these cars is the 10D.N. It has a very high average current rating with a stand alone voltage regulator. Having the regulator mounted on the radiator support with nice cool air on a steady section of the car is the best..
Actually the 10 DN variety came with 1963 to 1968.
Starting in 1969 with the Corvette, the 10 SI began to be installed.
BY 1973 10 SI style alternators where installed in most GM.

Since 78Elk has a 1978 he originally had a 10 SI or newer. Since he has an earlier 1973 engine, we don't know if the 1973 10 SI was moved with the engine into his 1978.
 

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Discussion Starter · #17 ·
Thank you for your information. This alternator came out of a 79 Malibu with a V6. I put it in the Elk, myself. It's been there since 2001. Is it possible that the regulator is bad? This problem seems to have started, after I started using the trickle charger and leaving it on all the time. Could it cause damage to the alternator?
 

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Thank you for your information. This alternator came out of a 79 Malibu with a V6. I put it in the Elk, myself. It's been there since 2001. Is it possible that the regulator is bad? This problem seems to have started, after I started using the trickle charger and leaving it on all the time. Could it cause damage to the alternator?
"Could it cause damage to the alternator?' It will cause damage to your battery (overcharge). Get a battery minder.
 

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regarding checking your alternator....

we use a device at Advance Auto that we can check in the vehicle itself. we hook up to the battery, input the battery specs and vehicle specs, start it, idle it, rev between 2000-3000 rpm, then shut down. that gives enough info to determine battery state as well as current draw and how much output your alternator is pushing, as well as the state of your starter and what it was pulling. that will give you a good idea of what is going on.
 
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