Alternator Lesson

[Bob Chadwick]

Had a little bit of an incident Saturday that had me get my charging system checked out. Battery is fine but the voltage regulator us shot.

I need a lesson in alternators. I think mine is the original, with 55A stamped into it, a sticker indicating "Changeover" on the side of it, two wires going into a plug, a battery wire and a ground. I've started to look around and can get the stock replacement from NAPA for about $40.

I think I want to go with a little larger capacity unit with the MSD box and a future thought to electric fans. I've been looking at the 80 - 100 amp units Is there any problem or benefits from doing so?

All of higher amp alternators appear to be advertised as one wire units. Can someone tell me what that is all about? Do I need to buy some kind of conversion kit?

They seem to come stock, painted black, powder coated, polished aluminum or chrome. If I wanted to dress up the engine compartment is there any drawback, other than price, to the various finishes?

What about manufacturers. The most commonly advertised unit in the catalogues appear to be Delco, Powermaster, Proform and East Coast Auto Electric.

And finally, I've got the unit out but had to remove it with the bracket cause I couldn't get the bushing out. How do I do that? A punch of a certain size?

 

[SPANISHVETTS]

Had a little bit of an incident Saturday that had me get my charging system checked out. Battery is fine but the voltage regulator us shot.

I need a lesson in alternators. I think mine is the original, with 55A stamped into it, a sticker indicating "Changeover" on the side of it, two wires going into a plug, a battery wire and a ground. I've started to look around and can get the stock replacement from NAPA for about $40.

I think I want to go with a little larger capacity unit with the MSD box and a future thought to electric fans. I've been looking at the 80 - 100 amp units Is there any problem or benefits from doing so?

No problem at all as long as you stay with the same size case. I believe that you car has a Delco 10 SI alternator case. If so there are a lot of aftermarket high-output alternators available.

All of higher amp alternators appear to be advertised as one wire units. Can someone tell me what that is all about? Do I need to buy some kind of conversion kit?

The 1 wire (self energizing) units do not need the wire from the charge light to start the alternator. I would stay with the standard Alternator and continue to have the charge light functional. If you do go with the 1 wire no conversion kit is required.

They seem to come stock, painted black, powder coated, polished aluminum or chrome. If I wanted to dress up the engine compartment is there any drawback, other than price, to the various finishes?

As far as paint or chrome goes it is what you like. The electricity will never know the difference.

What about manufacturers. The most commonly advertised unit in the catalogues appear to be Delco, Powermaster, Proform and East Coast Auto Electric.

I would stay with Delco or a rebuilt unit using the Delco case.

And finally, I've got the unit out but had to remove it with the bracket cause I couldn't get the bushing out. How do I do that? A punch of a certain size?

I have never seen the bushing stuck in the bracket. Can’t help you there.

 

[Bob Chadwick]

Thanks for the info.

I ended up ordering a one wire unit just because of the flexibility. I ended up going with a JEGS unit that was polished aluminum.

JohnZ indicated that Lectric Limited made a conversion kit. I went to their website and found two kits, VAK6896CS and 500295, and was unsure if which one to go with. I called them and spoke with their tech support and their were unsure as well.

VAK6896CS is described as a "ALTERNATOR CONVERSION HARNESS, simple plug-in conversion allows use of a CS (serpentine belt, external fan) series internally regulated alternator in place of the original SI series internally regulated alternator."

500295 is described as "ALTERNATOR CONVERSION HARNESS, simple plug-in conversion allows use of a CS or AD (serpentine belt, internal fan) series internally regulated alternator in place of the original SI series internally regulated alternator."

 

[Bob Chadwick]

Now I'm really confused. I did a little digging around and came up with some information against going to a 1 wire alternator at a Mad Electrical.

I ended up canceling my order until I can get some more information.

 

[Vettehead Mikey]

From an opposite point of view and with all due respect, none of the aftermarket changes you are planning on making will improve the performance of the car in any respect, but only succeed in making it 'different'.

MSD ignition is a waste of money on a street engine. Electric fans (in my mind) are Bubba's own handywork with no return on investment and the stock alternator puts out more than enough juice as-is.

I just don't understand the perceived need to re-engineer the car by going through a Jeg's catalogue.

I know the electric fan (and fuel pump) topic gets thrashed to death every few months with each side conveniently twisting the laws of physics to suit their needs. I hope this soap boxing doesn't set off a new round of debate.

 

[Bob Chadwick]

Mikey,

No offense taken. That's why each have our own car with our own vision of it.

Bob

 

[SPANISHVETTS]

Bob, I do not want to do a lot of chest pounding and saber rattling but alternators are one of the three things that I do best. (The other 2 change to meet the need ) No joke, before I did the sailboat thing I spent about a year learning how to fix the things that you can’t buy in Timbuktu. I did a 6 week stint at an Auto-Marine electric shop in St. Pete where the owner made sure that I could build a 10 SI out of junk.:eyerole



If the car was mine I would go with a hi-quality hi-output 10 SI rebuild or aftermarket unit. The 10 SI can go up to 80 or more amps with out problems. Again stay with the standard unit so that no wiring needs to be cut or eliminated.:bash
Lots of people build these things. You can even buy one from JCWhitney.



Both of the Kits from MAD are designed to connect the newer CS series to the SI plug. They do not address the 1 wire alternator installation.



The SI unit is a thousand times better built than the newer CS ones. Like everything else the General keeps learning how to build alternators cheaper and cheaper. i.e. The SI diode block is connected by screw terminals while the CS diodes are soldered in with special hi-temp solder. In other words you can rebuild a SI in candle light with your Leatherman knife while repairing the CS would require some skills and tools.



I would go for the alternator with the best warranty. Not because you expect to use it but because it indicates that the manufacture used parts that he thought would last.



BTW: Delco still makes several versions of the SI that are recommended for use in hostile environments.

 

[Bob Chadwick]

I went with a Powermaster that does one and three wire. It says it is the SI style but not knowing the difference between a CS or SI did I do good? :confused

Thanks for the help.

 

[SPANISHVETTS]

did I do good?

Yep, real good Powermaster has a good reputation.

 

[photovette]

Make sure you run a more robust charging wire to the starter motor connection point (to battery) and get rid of the fusable link. I have a 165 amp alternator and have run a 4 gage wire from the alternator. I also put in a high load auto-reset circuit breaker instead of the fusable link (see image).

I have to agree that wholesale changes from a catalog are a bad idea--I always found that going back to as stock (in most instances) makes a C3 much more dependable--I don't care how fast it got me there, it's getting me home again that counts.

When I want to make improvements, I look at what was done to the newer C3's as a guide--those modifications that were designed, tested, and installed in C3's by GM. For instance, I put an aux electric fan from a '81 'vette in my '77. I also put in a fiberglass rear spring in as found in the '81 also. Refinements such as those are a safe bet.

However, I did convert my sealed beam headlights to H4's and my combined headlight bulb amp draw, when running high beams, is 65 amps. A new alternator was definitely needed. But I can see at night now, so it was worth it.

And, you don't need to buy a new alternator to get more amps--any alternator shop can rebuild your existing alternator to give you up to 250 amps--usually while you wait.

 

[JohnZ]

And, you don't need to buy a new alternator to get more amps--any alternator shop can rebuild your existing alternator to give you up to 250 amps--usually while you wait.

I agree - no need for weird adapter harnesses and unobtanium-plated nuclear-whizbang Jeg's/Summit alternators; any alternator shop worth their salt can rebuild your original with more output. I've had several done for project cars that went in as standard 37-amp units and came out as 61-amp for no extra charge, as the shop doesn't carry the old 37-amp parts due to their low volume. Could have had them rebuilt as 80-100-amp for another ten bucks, but I didn't need the power. Alternators are pretty simple devices, and a good shop can do almost anything with them without altering their externals.

 

[Bob Chadwick]

Thanks John.

 

[joe1975]

I've read posts where they claim a higher amp alt. will fry wires, old wives tale?

 

[JohnZ]

Alternators only put out the amperage that's demanded by the devices connected to them; if you have added devices that pull two or three times the amperage that the charging system wiring was designed to carry originally, you need to upgrade the wiring to handle the increased load (and use relays to switch power loads).

 

[wishuwerehere82]

Bobchad,

I'm glad that you found your problem. Let us know if your missing problem is cured after you get everything straightened out.

 

[Bob Chadwick]

Alternator should come in today and I'll have it in either tonight or tomorrow. Hopefully the charging issue will solve the problem. I'll let you know.

 

[Nut]

bob.... if you go with the big juice alt do be sure to upgrade the main wire. 8AWG min for 105 amp alts or higher. Mine has a 85amp and that's just enough on the stock wire. Can't believe you had a 55 in there. Usually 63's were stock then. Let me know how this works out.

......... Bob

 

[Bob Chadwick]

It's all in and it seems to be working fine.

Now I have to see if the voltage issue was the cause of my high speed miss.

I will need to upgrade the wire but that isn't happening this weekend. Where does this wire go to from the alternator. It says battery but I didn't see any red wire on the battery.

I also need to get an extender harness for the VR plug as this one has it on the otherside and it reaches but with stress on the wire.

 

[smithjw]

Bob, did you ever upgrade the charge wire on your alternator? I'm just about to do the same as you. Powermaster 100amp alt. I'd like to know where the new wire should run to after the alt.

 

[Bob Chadwick]

I haven't got that far. I think it's supposed to go to the positive starter terminal where the heavy wire runs from the battery.