[70bird]

My alternator is the GM type (AC Delco) that has the small 2 wire white plug in it.
My alternator is wired in this fashon:
Alternator to hot panel on fender well. The battery is wired directly to this hot panel as well.
The little white plug in the alternator is wired this way: red wire to the main output wire on the alternator that goes to the hot panel. The black wire goes to the fuse block.

Does that sound correct?

Here are a couple more alternator related questions (some of which are the reasons for concern which led me to start this thread):

Is it normal for alternators to get pretty hot? You can touch it, but you wouldn't want to leave your hand on it for more than a couple seconds.

My volt meter rests at about 11 volts at idle (600 rpm) and jump to 14 volt once I get going. Is this acceptible?

On some GM alternators I have noticed that there is a jumper wire on the little white 2 wire plug. This jumper connects the red and black wire that go to the plug. What is the purpose of that wire. My neighbor cut this wire on his 66 Impala (which has many problems) for no good reason other than he thought it didn't look right.

I appreciete all the the insight I get from you guys. I didn't build my Firebird. Every time I get into any part of it I find that it was done either half a**ed and/or not how I would have done it. I have been redoing everything that was already done (a little over 3000 miles ago) with much help from you guys.
Thank you.

[docvette]

Doc here,

Do you mean by hot panel, the single terminal with Fuse link on it? Comes from the starter main bolt?


See the attachment, Is This for your 70 Bird? If so you should (if it is stock) have an External regulator on that car..hidden under the fender well somewhere...The Book says pre 73 GM automobiles had external regulators...If so the Attachment will apply.and if so..then no..it is not correct...

If It IS internally regulated (73 to 84) the wires should be thus:

• Red=goes to fuse link and starter lug
• Red/Blk=Goes to the red wire
• Brown=goes to the Charge indicator lamp and through that to power (20 fuse marked Gauges)

An alternator will get hot in the course of power generation, however the majority of the Heat you are experiencing is PROBABLY, heat transference from the engine/alt.mounts them-self. You could use an old kitchen meat thermometer and test the manifold temp, then take a reading at the Alternator case..it should not differ more than a few (10 to 20) degrees...


No, an alternator should produce Voltage (maximum) at any speed...If you have an External Regulator, It may need adjustment on the field and air gap contacts (about 00.17 and 0064 ) Or it may need replacement..If your alternator has an internal regulator, you may have one or more diodes out..you need to address that by replacing the diode pack (s) or the regulator...or the alternator if you don't want to pull the old one apart..The charging system should never be at 11 volts..If it's working correctly.


Yeah, I've seen this too..not sure what it's for...If I had to venture a guess, I'd say it's for self excitation of the alternator .. where the light or gauge has a different source for sample...I do know without it..it won't charge...Test by running it, with the jumper and measure the voltage. should be 14.4 volts at idle..and place a screwdriver at the back of the alternator shaft bearing area..It should have a magnetic attraction...if it's charging. Remove the jumper, and it should drop on voltage readings and the attraction should stop..meaing the alternator is not charging..

Doc

[HotRodMan]

I was just wondering how Docvette acquired all his information about electrical systems? His knowledge always astounds me.

[horvath]

Me too ... the Doc is a real bonus around here!

Here's how my alt is setup:



Alan
54 Chevy Pickup

[70bird]

My firebird has very few stock features left. The wiring has been hacked up and only a couple factory wires remain (exterior lights and flashers). The hot panel is just a brass panel on the finder well that is hot all the time. It has several wires running to it. It is not wired to the starter at all.

The only wires to the starter are the battery wire and ingition wire.

I'm not sure what you mean by fusable link. Is a fusable link what it's name intails? It can power anything while using a fuse to safe guard the connection.

The alternator is pretty new, it's an AC delco reman. unit. My guess is that it is internally regulated.

Can the diodes be purchased from an auto parts store? I've never been inside an alternator before. Sounds like a good time to check one out.

[docvette]

Doc here,

Your wiring for the car SHOULD be arranged thus:

• One main Cable to the Starter Solenoid.
• One 3 wire Fusible Link from the main Starter Bolt
• One 10 gauge wire from the link to the main fuse buss (or single terminal holder on a fender well to fuse buss)
• One 10 gauge wire to the horn relay
• One #10 gauge wire to the alternator power lug.

That's stock set up..and a pretty good arangement..for both access and safety...I don't know about a "Brass Panel" ..sounds like it might be conducive to shorting..(things falling on it...)

Fusible link...here is one..It acts as a high current fuse...Located usually at the main starter bolt, or main power feed from the Battery (single terminal , terminal block)



It's sole function in life is to melt or burn up when the circuit sees current levels higher than the harness wires can support..instead of burning up a harness...

It can handle higher currents than a fuse, and opens up slower than a fuse would (takes time to melt) If you DON"T have one...I'd honestly suggest you install one...Your courting disaster if you have a massive short...like your rod going up in flames...

You can buy the diodes for about $10 at just about any auto parts store...Simple and easy to replace,

• Remove the alternator
• half the case by removing the 4 bolts
• locate the diodes on the back of the alternator rear end bell...
• When you get it apart, remove the 2 or 3 bolts and remove and replace the diode pack..
• If when reinstalling they don't give you some heat sink compound, you can score a tube at the parts store when you pick up the diodes...

you'll note it mounts to a heat sink generously apply compound to the diode pack and heat sink..It will last a lot longer if you do this..wipe any excess off, it will spread if it contacts rotating parts..When you tear it down, It should look like this:



HOWEVER, If you are going to do the work, I recommend you get a rebuild kit..they can be had at about any auto parts store for about $15 to 25 bucks...The Kit looks like this...



In addition to the procedure for replacing the diodes as above, spay it own with gunk, hose it down and let it dry...

• locate and remove the brushes and spring followers
• replace the spring s and new brushes into the holders

TIP:If you look where the brushes ride on the rear end bell, you'll note two holes one below each brush..bend and insert a paper clip here to hold the brushes up so that the end bell will just slip right on to the shaft/rotor assy...(no jockeying to get the brushes in place ..)

• Remove and replace the bearing from the end bell
  
  TIP: get a SMALL sharp punch and make a small punch mark on the end bell each third of the way around..If you do this, it will make it slightly more difficult to reinsert the end bells..BUT the bearings WILL NEVER SPIN..
• Lastly remove the diode pack for the internal regulator (if so equipped)
• If it is mounted on a heat sink..use the compound as you did the Diode pack..

Clean the brass pickup on the rotor assembly with a fine emery cloth, burnish it until it's shiny and bright..

Replace the end bells over the rotor Assembly and bolt the four bolts back up..OH..and don't forget..remove the paper clips..

You should be All good!

Doc
=================================
HOTRODMAN:

I've been street rodding for about the last 35 or so years...a lot of my info comes from trial and error over the years, and whatever the book provides..

Believe it or not, My career background, (now semi retired ) never included autos at all
I was a Pilot trainer for a major air carrier's flight training center.. for 15 years and retired at age 38...
I got bored, had an unused EE from my pre Airline days..and opted to start a few related businesses...
So for the past 15 or so years I have been building things like ENG's.. (Electronic news gathering vans..or TV news vans) and video production trailers for onsite production centers..(like court TV uses for long trials..)
I also Design & Build Studio to transmitter links..(2 to 30 ghz Television Transmitters or exciters..and final P.A bricks..the other end of that big dish on the news vans...)
I also have been in Broadcast Radio and TV for the last 15 years.. (all phases..from jock to station owner..)

In addition to that, I have always (since age 17) owned at least one Corvette in addition to all the street rods that had no right to exist in nature......

Being Cheap..decided it best to learn all (I could about wrenching on them) So yeah,,I'm high mileage, but still around...

So that's my history in brief..It really could get longer ..but those are the basics..
=====================================
ALAN:

Thanks Bud..

It's also good to know you got my back when I screw up..as I do from time to time..have learned some stuff from you too!

Doc

[horvath]

70bird: Here's what I learned about fusible links -- READ THIS

Alan
54 Chevy Pickup

[70bird]

The MAD Electrical site has a lot of good info. Thanks Horvath.

I like this diagram:

http://www.madelectrical.com/newstuff/

I'm going to pick up one of these systems for my car. It will give me piece of mind.

I'll rebuild the alternator also.

[horvath]

Mad Electrical rules!

That's basically the system I applied and the results are phenominal.

Alan
54 Chevy Pickup

[m1e9r5c6]

Instead of the diode, I used a warning light that had 10 ohms resistance (equivalent to a 4 watt bulb). I prefer to have the warning light AND a gage to monitor things a bit better. It seems easy to forget to look at the gage, but you sure don't miss a big red light!!

[docvette]

Doc here,

Something I learned From my old airline Flight training Center Days...and is taught in basic flight skills, Is the Panel "T" Scan...

Every Few minutes or so (mentally set your own clock) Make it a habit to scan the instrumentation, from first, Left to right, back to center and down...(adapt it to your panel) looking for aberrant readings...

At first you have to "Force " the scan..but shortly it will become second nature...

I have never Trashed an Engine (automotive OR aircraft) due to a Missed reading or red light...Good habit to form...

In addition to that..It Has kept my Cruise speeds on the open highway down..( no citations..) as well as looking both left and right LONG before approaching an intersection..Green light or not..

(I was T boned once before about 30 years ago in an intersection, on a green..since then I have made that a second nature scan, and It has never happened again.. Had some close calls I was able to avoid because of it...but not hit again..so "rote" (sp?) Training actually pays off..

In a Street Rod (like aircraft) Those readings will change all the time due to various driving conditions , and rapidly, A Good Timed "T" scan will pay off in saved engines alone!

In a one hour drive, on a 3 minute timed "T" scan..you will have checked automatically, your : Oil Pressure, water temp, Charge rate, Speed, RPM, and any other related illumination Device 20 times! And never realize you did it!

Doc

[horvath]

Thanks for the info, Doc.

I love my gauges ... I put Dolphin gauges in my truck 2 years ago ... and am in the habit of scanning them constantly while I'm driving. Especially after first getting the truck and seeing the electrical system doing psycho-antics and the engine overheating regularly, I really enjoy seeing everything copasthetic (except the gas gauge, LOL).

Hey, Nate ... what does the red light do? I mean why use that instead of a diode??

Alan
54 Chevy Pickup

[m1e9r5c6]

I didn't mean to imply that I don't scan my gages. In fact I do the same as you Doc, but because of the position of the volt meter and fuel gages in my truck (under the dash by my left knee due to space constraints in the dash) I find it is tough to see at times. That's why a light is a good thing. I would definetly NEVER opt for a warning light INSTEAD of gages. The light is just a good back up.

As well in this case, you can get the light pretty cheap at your local auto parts store. The diode will have to come from an electronics store. For convenince, IMO the bulb would be easier to replace if stuck in "Nowheresville" rather than a diode. That said, either will work. It's up to you.

[66Caprice]

Originally Posted by horvath

Mad Electrical rules!

I second that! The New System kit has everything you need to make your electrical system under the hood like new. The documentation is excellent too.

Dan

[docvette]

Doc here,

I have the same problem on the 80 Vette, When the seat and steering Wheel is properly positioned (for me) I can't see the Speedo, and half the gauges in the center Console because The dang wheel blocks vision!!

Don't have the problem on any of the 76's at all, just the 80..(Another Corvette Milestone For 1980... )

Was thinking of swapping out the Tach (which is sitting on the left) with the speedo (which sits on the right of the cluster) and move all the Important gauges to the extreme right in the center console ..was further thwarted by modern technology..the laminate cards...not wanting to hardwire both clusters in lieu of the laminate cards..my second choice applies..."Learn to Lean..."

One other thing we didn't discuss here, Do you have an electric Choke? If so you may want to parallel the coil control circuit from a relay from the field wire..and the N.O. C.W. contacts to power and the Choke terminal respectivly...

This will give you a Choke function that will ONLY operate while the engine is running...so as to prevent a full open Cold start should you happen to have the key on for 3 or more minutes prior to start on a cold engine..which then defeats the purpose of the electric choke..

The relay is also a good first line of defense in the case the alternator Diodes begin to go south...It will chatter and sound like a electric shaver..at the first sign of diode damage..It is also the way Stock GM set up the choke.

As for the diodes, you can get 1N4001's at rat shack in a 4 pack for like about 3 bucks..and throw the spares in the glove box..HOWEVER, the diodes will outlast the light by about 10 times lifespan, simply because their Semi conductor..But as you said...It is comforting to have the light as a backup..

Doc