alternator question

[Zs-ondabrain]

E = Earth as in a ground. If it looks like a tapped shell, then it's likely a ground. Unless it's on an actual terminal.

[Zed Head]

Edit - I'm still slow.

Edit 2 - Wilson, if you get the MSA plug, it's just unplug the external reg., plug the adapter in and follow the directions for connecting the other wires. You don't even need to remove the old external reg. unless you want to.

FastWoman, I think by "e" he means the E which is hidden under the spark plug wire (?) in his picture. Earth, i.e Ground. It is there to ground the alt. housing. It is not a good connection point for all of your other grounds, ground to the block or frame or a junction block connected to your negative terminal.

Wilson, I would buy that plug from MSA first and use it to do your internal reg, alt. swap. It just takes the place of your external voltage regulator AND it already contains the diode. It would be the simplest way to go. You'll have to get some Chevy hardware though for your new alternator, that mounting bracket in your picture is elegant (I like it) but looks like it fits Datsun.

The ammeter and junction point for future loads can be handled individually and separately. You have a lot of stuff going on.

Edited December 14, 2010 by Zed Head

[FastWoman]

Edit: Ha! You beat me this time!

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I think the "E" might be for "earth" (British for "ground.")

If you're going to an internally regulated alternator, you'd be removing your external regulator. I think the three connections on a GM 3-wire alternator are:

1 - alt light (grounded when alt problem). Hook warning light between terminal 1 and +12V IGN

2 - +12V voltage reference (to BAT circuit)

BAT - The main current output.

I believe you can simply hook up the main cable and run a jumper between the output post and the #2 terminal.

I'm guessing with the voltage regulator removed, there won't be a backfeed problem. I'm also pretty sure wiring the #2 to the battery (per instructions I googled) won't result in current draw when the car isn't running. That's the OEM configuration of my '78's wiring. I imagine a GM 3-wire is supposed to be wired the same. However, I'll leave it to you to study the back-feed issue when 240's are upgraded to '78 alternators.

Edited December 14, 2010 by FastWoman

[wilson_wwsc]

think this would work as the lower mount? http://www.summitracing.com/parts/SUM-G4050/

I already have something similar to this: http://www.summitracing.com/parts/SUM-G4049/

Going to order parts tonight. =)

I'm slow, what is the difference between 2 and BAT? 2 goes to the starter, and BAT goes to + terminal on battery?

[FastWoman]

I haven't a clue about the brackets. I didn't even know a GM alternator would mount up to an L24.

Here's a helpful diagram for you...

http://www.novaresource.org/alt/chargcircuit.gif

On further reflection, I think running the volt reference (#2) all the way back to the fusible link would be a good idea. My OEM-configured '78 had a branch connection internal to the harness near the alternator, but if there's any voltage drop across the main output wire, the better reference would be closer to the battery. I guess I'll rewire mine that way someday, if/when I'm ever back inside the harness. Wish I had thought of it earlier.

[wilson_wwsc]

so is the function of # 2 a backup for the situation where indicator lamp blew up? The alternator would stay on even if the starter swtich/lamp failed?

That cartoon sure makes it look simple

[FastWoman]

No, #2 reads the output voltage. If the voltage is too high, output is cut back. If it's too low, output is increased. In other words, #2 is the input to the internal voltage regulator.

#1 is simply the "alternator malfunction" switch for the "ALT" warning light (if you have one).

It's just as simple as the cartoon! I put a GM alternator in our Chrysler boat and wired it exactly that way.

Two other notes:

(1) Make sure your ground is every bit as heavy as your output wire. Current has to flow through it too!

(2) You can make a great lug for the end of your wire out of small-ish diameter copper tubing. Cut a piece maybe 1 1/4" long. Insert your wire half way and crimp the tube around it. Then flatten the other half of the tube in a vice, and drill a hole through the flat end. Next, infuse the connector with solder. (You might need to hit it lightly with a torch if your wire is too heavy and/or your soldering gun is too light.) Finally, put a bit of heat shrink around the crimp end of the connector. That will give you a far more substantial lug than you're going to find at the auto parts store.

[wilson_wwsc]

one more question for now: just to make sure, even if the circuit for #1 breaks (bulb burns out), the alternator would still function?

I've never thought of making a leg out of copper tubing! So much cheaper than ordering online! I love making my own things that I don't have to buy at a premium =)

[FastWoman]

Yes -- A burnt out bulb or disconnected state on the #1 would not keep the alternator from running.

Have fun with your project! Show us pics once you've got it done, OK?

[wilson_wwsc]

Well, with christmas shipping times, I might not be able to get parts for a little while, but here is a sneak peak of what my car looks like:

less of a peak than full exposure, but there are some cool things you don't see from this side angle

[FastWoman]

Cool! It's been a while since I've seen a two-tone paint job!