Just converted to internal reg. alt-check my work?

[spenceman72]

I just converted today to an internally regulated alternator, and after much research on these boards I thoroughly over complicated this project but "think" I've done it correctly.
I followed these instructions exactly, thanks to Todd for keeping it very simple;
http://67-72chevytrucks.com/vboard/s...d.php?t=119379

The battery was at 12.4v and jumped to about 13.3 while the engine was running (shouldn't it be 14.4 or so?). The alternator wasn't making any crazy sounds so I believe the belt tension is good.

The alternator I installed is an Ultimate, part 01-0260.

A couple questions I have;
1. Other than testing voltage at the batter with/without the engine running, what other tests should I do to make sure I installed everything correctly?
2. The description of the alternator says the clock position should be at 3. However mine is at maybe 2 (I believe the clock position is the position of the tabs when looking from the back of the alt). If I had it at 3 the belt would be very loose. Is this an issue?
3. My 72 Blazer has gauges I believe (speedo, blank, fuel on top and battery (read out is d on lt side and c on right), temp, blank and oil pressure on right). I read several time that when converting to an internally reg alt on a truck with an ammeter (that is the 'battery' gauge I believe), you will need a resistor somewhere on the brown wire (the one I connected to the blue wire. Well-mine doesn't have any resistor. With the engine off the battery gauge sits right in the middle, and with the engine running it pegs at 'c'. So-do I need a resistor?
4. This new alternator says it is 78 amps. I have AC on the truck that doesn't work, a regular aftermarket stereo and did install a heavy duty headlight harness from LMC. I'm assuming I'm fine with the alternator I purchased in terms of what I have in the truck, but I did not change the red wire that connects to the bat terminal at the back of the alternator..It looks to be 10 gauge...is this 'big enough' for the alternator?
5. The red and white wires that were plugged into the old external regulator-I just left them in the harness. ok?

My biggest 'fear' is burning down my house or Blazer-second is the truck just dying on me while driving and I go into a ditch, and third is just being stranded somewhere. So-any advice/comments on how I did this and things I should check to make me more comfortable are greatly appreciated!

[davepl]

Rather than your home made terminals in the alternator I'd go to any auto parts store and pick up the right connector. It's just a two-spade female packard connector, and they sell them as alternator connectors.

I'd also recommend soldering the connections. Not just for a better physical connector (crimp connectors do fail from time to time) but also a better connection, since this is the heart of the charging system.

I think 13.3v is OK if your battery wasn't depleted.

When I converted to CSI I had to re-clock the alternator (which I didn't know you could do, but I tried, and did). I don't think it was impossible to install as it was shipped but the connectors wound up in a better spot.

[sKnNyPpY]

Jumper the plug like VetteVets directions in post 13 of this thread and you should get 14v. http://67-72chevytrucks.com/vboard/s...d.php?t=601025

[engineer_gregh]

You could have some "voltage drop" because of the wiring and the jumper method you used from terminal 2 to the hot post at the alternator. I followed the directions from this thread other than I didn't cut any wires. Remember, white to number one terminal and blue to number 2 terminal. Let us know if this takes care of your amp gauge problem.

http://67-72chevytrucks.com/vboard/s...d.php?t=622743

[spenceman72]

Originally Posted by engineer_gregh

You could have some "voltage drop" because of the wiring and the jumper method you used from terminal 2 to the hot post at the alternator. I followed the directions from this thread other than I didn't cut any wires. Remember, white to number one terminal and blue to number 2 terminal. Let us know if this takes care of your amp gauge problem.

http://67-72chevytrucks.com/vboard/s...d.php?t=622743

OK-I just rewired. Now I have the red and blue wires jumpered and the brown and white wires jumpered. I have the red wire at #2 and white wire at number 1. You state the blue wire at number 2, but the link you provided has the red wire at #2..does it matter? The blue wire at the alternator isn't connected to anything. I then ran a 10 gauge red wire from the bat terminal on the alternator to a junction that looks just like the diagrams in the picture.

With this re-wiring, I am now showing 14.4 v at the battery with the engine running, versus 13.3 or so with the jumper method.

Once I get confirmation regarding red or blue on 2 I'll clean everything up.
Thanks guys!

[engineer_gregh]

It does matter. The only red wire at the alternator should be the thicker red wire and it goes to the hot post that goes over to the battery. If you are still using a jumper from the hot post to #2 take it off and plug the blue wire there. Vettevet gave an illustration of how to clean up all of the wiring if you want to but it does require more effort and time. I personally didn't want to open all the wiring bundles involved and do all of that. Make sure to read the link I sent you all of the way to the bottom. The last two replies really sums it up. Keep us posted on how it works. Thanks

[spenceman72]

Originally Posted by engineer_gregh

It does matter. The only red wire at the alternator should be the thicker red wire and it goes to the hot post that goes over to the battery. If you are still using a jumper from the hot post to #2 take it off and plug the blue wire there. Vettevet gave an illustration of how to clean up all of the wiring if you want to but it does require more effort and time. I personally didn't want to open all the wiring bundles involved and do all of that. Make sure to read the link I sent you all of the way to the bottom. The last two replies really sums it up. Keep us posted on how it works. Thanks

Ok-now I seem to have fouled everything up. I read the link including the two posts at the bottom and decided to clean things up like Vettevet illustrated.
Here is what I have;
Got rid of the blue wire altogether. I have the brown wire spliced to a white wire and sitting on number 1 (the left). The brown wire wasn't long enough thus splicing to a white wire. I have a red wire going from number 2 to a 'junction'-more on this in a second. I have a red wire from the Bat going to this 'junction'. The junction is just what is shown in the diagrams-it is where the 2 red wires from the alt come together with a black wire/white stripe that goes back to the firewall, a red wire that is coming out of the firewall and another red wire that runs across the rad support to a little junction box where I've got some headlamp wires running to it and then a red wire to the pos bat terminal.
I checked voltage at the battery, the little junction of wires and the bat post on the back of the alt, and all read 12.58 without the truck running.
Got in the truck-when I turned the key just once to on, my batt gauge buried hard into 'd', and the truck wouldn't turn over-it wouldn't do anything in fact.
When I turn the key now, nothing at all happens-battery gauge/ammeter in truck doesn't move, nothing.
Now, battery still registers 12.58, but now I can't even get any voltage reading from the alt or where I connected the wires (#2 and bat from the alt, red wire and black/white wire going to the cab and red wire running across the rad support).
Seems like I blew something somewhere. Nothing works-headlamps, radio, nada.
I've gone over it a dozen times and it seems that I've got everything wired per the diagrams and instructions.
Help!

[davepl]

For anyone else coming across this thread at a later date, a couple of tips related to this topic:

- Rather than cutting your regulator harness just make a jumper with two male spade connectors to jumper the wires without cutting anything. I then tape it up and tuck it away.

- A better option for people who want to retain a more original appearance is to gut a spare or dead regulator (or your original if you're daring) and make the modification inside of the empty regulator.

Mine has dual batteries and the regulator is where the sun don't shine, so I didn't go the fake regulator route on my truck, but have on other vehicles.

No matter how fancy you get anyone who knows anything will immediately spot the different alternator connector, but it still is a nice touch.

[spenceman72]

The diagram for cleaning up the wires seemed very straight forward so this is the route I took. I've gone over it many times now, and have just what is shown below. #1 is a white wire-spliced to the brown wire. Number 2 is a red wire and joins another red wire coming off of the Alt Bat connection with 3 other wires-just like in the diagram. A red wire that runs over to the battery via a junction box, a black and white wire that has what looks like a fuse built in, and a red wire..both of these are running to the firewall.

Whatever I did seems to have fried something. I have zero voltage at the 5 wire bundle described above, and nothing at the bat terminal at the voltage regulator. No lights, no power whatsoever, which I can't figure out unless I fried something. I keep thinking back to my earlier post where after I completed the rewire, I turned the key once and my battery gauge buried far left into 'd'. As you can tell, I'm new to all of this, but clearly something isn't right.
Thanks everyone

[spenceman72]

Quick update.
I found that the red wire that runs along the rad support was spliced and came undone. This explains not having any power at all. The red wire was spliced using a little yellow butt connector, and there appears to be a small brown burn mark on the connector now. I'm not sure if this was there before, but if not-now I'm worried that I've done something that might burn my rig to the ground.
This wire seems to be either a 10 or 12 gauge, pretty sure 10, and is running from the cluster I mentioned earlier and the one shown in the diagram (2 red wires from the alt (#2 and bat) joining a black/white wire with fuse and red wire running to the firewall, and then this red wire I'm talking about that runs across the rad support to a small junction box on the passenger side by the battery, where I've got headlight relays attached plus a 10 gauge red wire running to the pos battery.

Thoughts?

[engineer_gregh]

The short wire from the terminal on the right fender well to the battery is supposed to be a fusible link. Its purpose is to open in cases where a short like yours happens. I noticed that the O'Reily Auto Parts had fusible links in stock here in Nashville. I would recommend picking one up and installing it. The two red wires spliced along the radiator support is original but not with a yellow butt connector. Solder and heat shrink them together and that will prevent that from happening again.

[engineer_gregh]

spenceman72, I untaped the harness on one of my trucks that has not been upgraded to an internal regulator to verify how it is wired. Red wire from the fuse block is joined to red wire going to junction block next to battery, red wire from Bat terminal on alternator, red wire from voltage regulator, and black/white wire with in line fuse. Based on your above comments, I would add fusible link at the Junction Block to battery, clean up the splice you said came apart, replace the fuse in line on the black/white wire (I'm pretty sure this is what makes your amp gauge work), and give it a test.

[ERASER5]

I did the no cut wire jumper method on my truck. A quick tip on the jumpers, 1-3,2-4. Backwards or forwards it is the same. No hard thinking or strong words necessary.

At the alt connection, I bought the new correct plug and used a tiny screw driver to depress the tabs and pulled out the wires. did the same to the original plug, and installed the original spades in the new plastic holder. No cutting at all!

As to which wire goes to which side, I accidentally go it right the first time. It is a 50/50 shot. If the alt doesn't charge, swapping the wires is another whole 2minutes a best.

[spenceman72]

Originally Posted by engineer_gregh

spenceman72, I untaped the harness on one of my trucks that has not been upgraded to an internal regulator to verify how it is wired. Red wire from the fuse block is joined to red wire going to junction block next to battery, red wire from Bat terminal on alternator, red wire from voltage regulator, and black/white wire with in line fuse. Based on your above comments, I would add fusible link at the Junction Block to battery, clean up the splice you said came apart, replace the fuse in line on the black/white wire (I'm pretty sure this is what makes your amp gauge work), and give it a test.

Ok-I think I'm getting closer with all of this help!
I have a fusible link that I bought at Oreillys in fact, orange wire and says it is a 20 amp. Would this be appropriate for the red wire from the junction box to the pos battery post? If so, I'll install that one and solder the red wire running across the rad support.

[spenceman72]

Another question-I see a lot of posts stating the red wire from the bat post on the alternator should be run directly to the pos battery, and others (which is the diagram from Vettevet that I'm following) has this wire joining the others (#2 on alt, black/white, etc) before running across to the battery. This is how I was set up with the internally regulated alternator-want to make sure I'm understanding this correctly.

[ERASER5]

Directly by way of indirect splicing to the battery. Yes, that is how the factory did it.

[Captainfab]

subscribing for later

[RichardJ]

All Ammeters have a shunt and most have the shunt built into the back of them. The Ammeter on these 67-72 trucks use an external shunt. Current flows in parallel through both the shunt and the meter at the same time.
About 99% of the current flows through the shunt and less than 1% flows through the meter, but shunts are designed to have a specific resistance and to be used with a specific meter.
The shunt I have pictured is for a marine application and sold with the meter.

Chevy uses the segment of 12R wire I have pointed out with my crude blue line as the meter shunt. That segment of wire is actually serving double duty for two functions but it doesn't know the difference. Each end of that segment are connected to the two wires that go directly to the dash meter.

All copper wire has some resistance. If you shorten that 12R segment, it reduces the shunt resistance and the meter does not read correctly. If you increase the wire size of that 12R segment, it reduces the resistance of the shunt.
If you have splice in the 12R shunt segment, it will increase the resistance and a poorly done splice, even more resistance. With higher resistance, a higher % of current will flow through the meter and peg the needle as you mentioned in your first post.

[spenceman72]

ok-I think I have everything worked out now.
I had to replace the small glass fuse in the black/white wire (seems that this is what blew in my initial post when I said the bat gauge buried on 'd'). Replaced the fuse and now the needle moves slightly. I'm getting about 14.4 at the bat with the engine running (versus the 13.4 I had when originally doing the jumper from #2 to the bat).
With my very limited no-how I couldn't figure a 'clean' way to join the 5 wires (2 from alt, 1 running to junction box, black/white and red running to cab) together, so I basically twisted them as tightly as I could and then put on a generous amount of electrical tape. I tried my hand at soldering-but all I produced was smoke and a hot wire-clearly takes practice.
So-hopefully everything is good.
I did notice that all the diagrams show a wire running from the junction box (18b with fuse) to the top right location on the fuse (above a red wire and the black wire/white stripe). I do not have this wire nor has my truck (in the 2 years I've had it) ever had this wire. Could it be that on my truck (72 blazer with 350) has this somewhere else? What is the purpose?

Thanks again everyone!

[slikside]

Originally Posted by captainfab

subscribing for later

x2

[RichardJ]

>>I basically twisted them as tightly as I could and then put on a generous amount of electrical tape.<<

That repair will come back and bite you in the arse at a very inopportune time.

Find someone that does solder and has a suitable size soldering gun and flux. You need a uninsulated BUTT Connector and some Self-Fusing Silicone Tape (Rescue tape) that you can find easily at a Lowes or some flaps. Your electrical tape can't handle heat or water and will fall off in short order. The self-fusing tape does not have glue and can handle 500 *.

[VetteVet]

The 20 amp fusible link you mention may not be enough. I believe stock is 30 amp so you may find yourself stranded somewhere.

The 18b and 18 b/w stripe wires are your two ammeter feed wires that Richard J posted in post 18.

The FAQ post by Todd works but it fails to account for voltage drop in the downstream circuits by the various loads in the truck. This is corrected by moving the red sensing wire from the back of the alternator and connecting it to the multi wire junction as you have done.

[VetteVet]

The 20 amp fusible link you mention may not be enough. I believe stock is 30 amp so you may find yourself stranded somewhere.

The 18b and 18 b/w stripe wires are your two ammeter feed wires that Richard J posted in post 18.

The FAQ post by Todd works but it fails to account for voltage drop in the downstream circuits by the various loads in the truck. This is corrected by moving the red sensing wire from the back of the alternator and connecting it to the multi wire junction as you have done.