Hey everyone, I thinking about buying a 65 amp alternator from AutoZone, it's a duralast, anybody hear good or bad things about these, is 65 amps good enough for all the electrics on our cars, should I get more amps? Thanks!
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The problem with going to a higher amp alternator is that your wiring was only designed for 55 amps max. The higher the amps the larger the wires you need to safely carry that much load. You can probably get away with 65 amps but anything higher and you will have to install heavier gauge wires. As for the Duralast alternators I used them years ago before Rockauto and other online sources came along where you can get name brand for the same or less money. They were ok then but that was awhile ago.
JohnJohn Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
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I have a 63 amp GM style 3 wire alternator and it works just fine. It's fused with a 100 amp fuse. You'll see the red GEN light glow at bit when you're driving at night and stepping on the brakes, but 63-65 amps seems adequate and a vast improvement over the generator. I have to keep the belt tight to avoid a squeal. I take it you already have an alternator conversion.
DeanComment
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I have a 63 amp GM style 3 wire alternator and it works just fine. It's fused with a 100 amp fuse. You'll see the red GEN light glow at bit when you're driving at night and stepping on the brakes, but 63-65 amps seems adequate and a vast improvement over the generator. I have to keep the belt tight to avoid a squeal. I take it you already have an alternator conversion.
Dean
JohnJohn Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htmComment
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Because of the V belt and limited amount of grip it has on the alternator pulley, stay with the lowest amperage alternator that you can find.
If you can't find a 55 amp alternator, install a larger wire and fusable link between the alternator output and battery. For up to 73 amps use 8 gauge. For up to 101 use 6 gauge. Match the fuse size with the alternator rating.
Then install a 55 amp circuit breaker or fuse between the battery and original fuse panel (large black wire).Comment
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The only reason to go with a larger-amp alternator is for decent output AT IDLE SPEED. That is why new cars come with 130-amp alternators. They can idle all day long with the A/C and electric fan going without draining their battery. For a classic car owner, this is very important if you are in parades or slow moving traffic. It is also important for police and taxi cars that idle for long periods.
A one-wire only outputs when rpms are over 1,200 or so because that is the only way they can 'sense' the engine is running. So, don't go there and forget 'electric start' with a 1-wire. Electric start senses alternator output to STOP cranking.
MY SUGGESTION: Here's a nice 130-amp rebuilt alt for $60 (to your door) with no exchange. CLICK HERE
Plugs are available for cheap, at rockauto.com. Look for both of these:
STANDARD MOTOR PRODUCTS S737 ($5)
STANDARD MOTOR PRODUCTS S545 ($7)
I use an oversized pulley from (Chevy, Ford) any of these old generators OR alternators. They all fit if you use the short spacer that comes from behind the serpentine pulley. The spacer prevents the pulley from dragging on the case. Some folks use a double sheave because in order to produce 130-amps this alt drags down over two HP. The original generator draw was 1/2-HP, so the 130 amp needs a large belt surface area. I put one on my Y-block ('59 Galaxie), now there is NO problem running an electric cooling fan all day long at idle speed. I made the mistake of mounting a 75-amp Mustang alt. That dragged my battery down in parades. The 130-amp won't because it outputs 25-amps at idle speeds.
Here's a typical wiring diagram for a Squarebird but you can use it on your '63: CLICK HERE
Notice the blue area. It shows your GEN light but they put a resistor around the bulb. Know why? That bulb gets power from your key switch. If the bulb burns out, the alt won't sense the key is on and it won't charge. Do you need the resistor? Not if you can guarantee the bulb is good.
This setup works the way you would expect: Get in the car and turn the key to 'ON' (GEN light comes on). Start the engine (Gen light goes out). Throw a belt, (GEN light shines).
Look at your 63's original wiring diagram... Your gen light wire (green/red) already connects to your voltage regulator ('I' terminal). Simply extend that wire and connect it to your new alt harness where it calls for yellow/black (now, green/red).
Also notice both alternator connectors get tied to each other. So, only three wires come off the alt; red (+), black (-) and yellow/black (now green/red). That's it. That MEGA fuse (175-amp) is there in case your alt ever shorts to ground inside. It rarely happens but solid state components can go bad. The fuse will disconnect the alt before your battery drains, so you can drive home.
Bird-in-the-bush just completed this project. You should shoot him a PM and ask how he likes it. - DaveLast edited by simplyconnected; May 8, 2017, 10:31 AM.Member, Sons of the American Revolution
CLICK HERE to see my custom hydraulic roller 390 FE build.
"We've got to pause and ask ourselves: How much clean air do we need?"
--Lee Iacocca
From: Royal Oak, MichiganComment
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One of the problems you will have upgrading to a larger amp alternator is that the amp gauge in your dash carries the full load of the alternator. You don't have a generator light like earlier models. That will also have to be upgraded if you want to keep it.
JohnJohn Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htmComment
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Yeah, tough decision, I will have my alternator tested, if this one is bad, I will probably get the 65 amp duralast at AutoZone, they say they are triple tested before shipping to insure quality, I think it would pose less problems, also the extra 25 amps will work well. Are these aftermarket alternators plug and play, or is there something I should know?
Does anyone know if I can use my stock voltage regulator, it should I get an electronic one? Thanks!Comment
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John Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htmComment
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You can spend far more replacing your OEM alt and regulator, and end up with a weak system. Modern alternators are all internally regulated and you should question why all the car companies install huge alt's. But hey, it's your car and your money to do with as you please. - DaveMember, Sons of the American Revolution
CLICK HERE to see my custom hydraulic roller 390 FE build.
"We've got to pause and ask ourselves: How much clean air do we need?"
--Lee Iacocca
From: Royal Oak, MichiganComment
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Well, what should I do here, I'm running with a 51 year old alternator and regulator, I know it's not putting out what it should, should I get an exact replacement from Macs, or the bird nest, or Larry's,???? Is Thier stuff any better then anybody else's? Should I have my unit rebuilt? What would you guys do, if you don't mind me asking? Thanks!Comment
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I can tell you Mac's "stuff" is no better. I like the idea of the 65 amp Duralast alternator with the built-in internal voltage regulator. The only change you must make is to disconnect your voltage regulator and leave it in place for the stock look. Simple.
DeanComment
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What Dave is suggesting is to ditch your old alternator and voltage regulator and get a modern 130 amp one that has them combined inside the alternator. This requires you to change the pulley since the new ones have a serpentine belt, run a new heavy gauge wire from the alternator to the solenoid and install a fuse for protection. You will lose your amp gauge that's on the dash since it won't handle 130 amps. How do you know your present alternator isn't putting out the correct voltage. Did you put a voltmeter on to see what it is. Does your car have working a/c. If so I recommend going Dave's route. If you don't have a/c then you can probably get away with a 55 or 65 amp alternator and external regulator. What brand and how much you want to spend is up to you. If I was going that route I would get one from Rockauto.com. They have the best prices and we get a 5% discount.
JohnJohn Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htmComment
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JohnJohn Pizzi - Squarebirds Administrator
Thunderbird Registry #36223
jopizz@squarebirds.org 856-779-9695
https://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htmComment
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OK, I do have an A/C car, but its not working right now, when the car is off the battery reads 13.21 Volt, at idle it goes up to 14.85, at high idle 15.39 drops down to 13.56 lights on idling, up to 14.89 lights on high idle, drops down to 13.25 lights on, blinker on at idle, when I turn my lights on my indicators freeze on, when I rev the car they start blinking again. it seems like the more stuff that's on heater, tape player, lights, brake light, everything gets dimmer, it seems like it needs more power. maybe I should start with a new regulator, an electronic one since it looks like the original one is still on the car.Comment
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