Chevelles.com banner

1 - 9 of 9 Posts

·
Registered
Joined
·
74 Posts
Discussion Starter #1
I plan to eventually upgrade the alternator on my 67 Chevelle. It has the original 63 amp alterntor 3 wire with external voltage regulator. I noticed at night that with all lights on it goes from 14 Volts driving to 12 or maybe 10-11 at idle, then one time the
generator idiot light came on.

I am also planning to install a stereo system with amp and maybe add an electric fan to my radiator system. With all of these added power requirements I decided to go with a 138 amp alternator.

I can stick with the external amp and separate voltage regulator or go to the internal regulator/one wire alternator. The voltage regulator is new. Either way I can upgrade to a 138 amp alternator in either 3 wire or one wire.

Any thoughts on this or what you would recommend. Is the one wire alternator a significant advancement over the 3 wire to justify complete re-wiring and losing the idiot lights (I also have after market guages)? I sort of like both.

Thoughts and advice appreciated.

Thanks,

Ken McDee
 

·
Registered
Joined
·
74 Posts
Discussion Starter #2
Note: I have a 67 Chevelle Malibu and a 67 Chevelle SS so not to add confusion to the two separate questions I asked in this forum.

Thanks,

Ken McDee
 

·
Registered
Joined
·
1,413 Posts
I'm not 100% sure if you're wanting to compare a 1-wire to an externally regulated one because I don't believe I've ever seen a 138A externally regulated alternator. If you're comparing the 2 differny internally regulated ones (1-wire vs 3-wire) the following applies;

The 1-wire is actually a poorer alternator than a 3-wire one and it doesn't have anything special inside. It doesn't allow the light connection, requires revving to get it working (because of no light), doesn't have remote voltage sensing and isn't available in most parts stores. Now some do have an optional light connection that when connected can get rid of the 1st 2 problems.

The 3rd wire that doesn't connect to the idiot light is for remote voltage sensing. Whatever point you connect that wire to is where the voltage will be held at the regulators set-point. For example, connect it to the main power wire at the fuse box and the fuse box will be held to 14.2V (or whatever the alternator regulates to). Proper use of this can eliminate unwanted voltage drops in the electrical system.

Peter
 

·
Premium Member
Joined
·
1,261 Posts
Ken,
Did this swap myself last summer and couldn't be happier with the results. Check this site - lots of info.
http://www.madelectrical.com/electricaltech/delcoremy.shtml

John
PS - my idiot light still works.
------------------
TC# 958
'67 Elky 396/325 TH400
----------------------------
"Speed Costs Money -
How Fast Ya Wanna Go?"

[This message has been edited by phocksphyre (edited 01-21-2003).]
 

·
Registered
Joined
·
859 Posts
I am a fan of one wire technology and do not agree that it is a "poorer" design. In fact, it is a simpler design and if integrated to the electrical system is quite reliable. I have never had one fail on me to this day, so I don't worry about parts availability perse. I have used them on all my street rod applications and all my trifives and muscle cars with great results. I am picky about the brand I use tho......Powermaster or TuffStuffs only for me! I know these guys and they do it right and have real quality products.

You can get the idiot lights to work on most if not all the applications but I really prefer a voltage gauge if given a choice. If you design an adequate wiring harness around the increase amperage requirements, the voltage drops will be indistinguishable in your system, so remote voltage sensing is not really needed if your system is up to snuff....esp with high wattage devices. You will have to put all of your high wattage devices (fans, stereo amps and I even do the lights) on separate aux relayed circuits and DO NOT run these thru the fuse box. Also, do not charge the battery thru the fuse box either. Connect at least a number 6 wire from the alternator to the battery or battery post on the starter and don't forget to upgrade your fusible links or you might find yourself without power. This wiring upgrade will provide a low resistance path to feed both the battery and the loads. If your battery is in the trunk, you will need an upgraded cable to at least number 2. I am assuming that you are keeping the customary load on the fuseblock and should not need an upgrade, but I always supply another number 8 from the starter to the fuse block buss to take away any voltage drop between the feed and the block. This keeps the voltage higher at the block when the load gets high. Old wiring systems need this upgrade if accessories are added anywho.

In so far as turning on the alternator by reving the engine.......you need 1750 rpms of device shaft speed to get the alternator to come on. This is usually and easily accomplished with most stock pulley ratios (2.5 to 1)when just starting the car and letting it idle at 700rpms. Some may take a blip of the throttle above that to come on as one poster pointed out, but I do not see this as a problem.

Either selection in my opinion is a good one.

------------------

Steve "Jack'stands" Jack
Tech forum at Jack'Stands Cooling Forum
 

·
Premium Member
Joined
·
2,223 Posts
Everyone has his or her own opinion, this is mine. I would use the CS, I think the high amp is the CS140, so
that I can connect the idiot light. Not sure how you connect the idiot light
on a one wire and would like to see a diagram. Volt gauges are nice to have
but in time tend to be ignored. Nothing gets your attention better than a
red light. I like both.

On Chevelles the horn relay is the main power distribution point. I would
connect the alt output to the horn relay not the battery, using #8 wire (#6
would be better, but not needed). Connect the alt S wire to the horn relay, this will maintain voltage at this point at the set voltage about 14.2
V. No need to change the fusible link as this wire, batt to the horn relay or starter to horn relay on 72,
should not pass higher than original design current.

This is important! Any
add-ons, i.e. cooling fans or electric fuel pump, should be connected to the
horn relay not the battery. Depending on the sound system you install you
may want to run a separate fused circuit from the horn relay for it.
 

·
Registered
Joined
·
1,413 Posts
I like Elree's advice. If not using the horn relay as the splitter/terminal block then add another bigger one on the rad support nearby.

It is also possible you could also use a 94A SI-12 alternator, which will fit in the brackets a little better than the CS series, even though both do work. Unless you have a killer stereo and big fans a 94A alternator should work.

Peter
 

·
Premium Member
Joined
·
4,477 Posts
It is quite possible to have a working idiot light "GEN" while running a 1-wire alternator.

all in due time...



[This message has been edited by Coppertop (edited 01-22-2003).]
 

·
Registered
Joined
·
7,762 Posts
If you use Peter's suggestion a source car would be a 84-85 Olds Cutless Supreme with A/C. These run a large 12 SI but it's clocked towards the engine. The adjustment threads are metric so you will need a bolt. Last one ran me around $20.00 from the junkyard. A recently replaced unit that lasted 4 years on my daily driver.

Joe you keep on promising.
 
1 - 9 of 9 Posts
Top