Alternator

[Minkota]

What is the part number or car/truck year and model so I can purchase a internally regulated alternator. I tried using the part number shown in the stickie but parts stores tell me it’s back ordered indefinitely.

Also, what would be the best amp to choose for stock factory harness with A/C, electric fans, and aftermarket lights and radio. Just don’t want to burn truck up with too high an amp output. There is a possibility of going to dual batterie in the future.

[driller35]

i personally upgraded to the CS 130 , very easy to do and gives you all the juice you need , ill see if i can find the thread http://67-72chevytrucks.com/vboard/s...ator+upgrading , you will find in electrical board if link not work

[RustyPile]

Originally Posted by Minkota

What is the part number or car/truck year and model so I can purchase a internally regulated alternator. I tried using the part number shown in the stickie but parts stores tell me it’s back ordered indefinitely.

Also, what would be the best amp to choose for stock factory harness with A/C, electric fans, and aftermarket lights and radio. Just don’t want to burn truck up with too high an amp output. There is a possibility of going to dual batterie in the future.

That statement is incorrect.. An alternator generates only the amperage called for by the electrical items.. For instance: Lets say you have a 100 amp alternator.. If The AC and ignition is all that's turned on and their total amperage demand is 30 amps, that's all alternator is making.. Turn on the headlights and the demand goes to ~ 40 amps.. The alternator automatically ups it's output to meet the new demand.. The thing to consider when selecting an alternator it to select one that makes more amperage "wide open" than the total amperage demand of the electrical system.. A 130 amp alternator will not "burn up" any parts of the system just because it's more than what is needed..

[Stocker]

I went through a similar situation a couple years ago, got lots of great help & advice here. The one I got did the trick and I'm very pleased with it. It's a 94A alternator for an '85 Buick Riviera, O'Reilly's p/n ULT R111785A.

https://www.oreillyauto.com/detail/c...-buick-riviera

[tim_mc]

I currently use an ACDelco 63A 10 SI, P/N from Rock Auto, alt P/N 88864305, plug clock @ rear view 3 o'clock. $57.89 w/$25.00 core charge ($32.89).
It powers everything fine, but I have a mechanical fan and no high power draws like high wattage stereo gear.

However, I have notes in my spreadsheet that if needed I can upgrade to 85A 15 SI, ACDelco 334-2128 {#19135686, 88863357} or 78A 12 SI, ACDelco 334-2156A or 335-1094, 3 o'clock.

[Greasey Harley]

I just did this conversion, I went with a 10si. I ordered an alt for a '79 Monte Carlo with A/C.
Here's a link to that thread:http://67-72chevytrucks.com/vboard/s...d.php?t=820083
A 12si alternator wires in exactly the same.
A CS series alternator hooks up almost the same, except you have to install a resistor.
Probably way more helpful than my thread; here's a link to the Faq by VetteVet: http://67-72chevytrucks.com/vboard/s...d.php?t=815300

[MARKDTN]

I would do a couple of things in your situation. I would get rid of the factory ammeter and go to a voltmeter. I would change to a CS144 (I would not use a CS130 as a paperweight). Delco #8077 pigtail is used if you have a lamp on the dash and the #8078 has a load resistor for use with no lamp to go from SI wiring to CS so you will have to do some adapting(different plug at alternator, but can use the same sense wires). Application for a 140A CS144 is '95 Buick Roadmaster. Then I would add a bigger wire from the alternator output to the battery. I might also add a junction block near the battery to power the fans and amp, that way you don't add any high loads to the original harness. While I was wiring, I would add headlight relays as well (to get brighter headlights and take load off the original switches and wiring).

If you don't want a CS144, then a 12si in either 78A or 94A. Anything bigger may have cooling issues. The 84-85 Corvettes do have a 12si that is 120A, but I would go CS144 if I wanted over 100A. 94A 12si is Delco 321-269 application '85 Riviera with 305Y, HD cooling and a/c. 78A 12si is Delco 321-244 application '85 Cutlass Supreme with 305Y. Nothing wrong with a 10si, I would just get a 12si if I was making the change since they have improvements. Don't use a 10si fan on a 12si, you have to get the 12si fan so be sure what you buy has the fan on it.

[Minkota]

Originally Posted by MARKDTN

I would do a couple of things in your situation. I would get rid of the factory ammeter and go to a voltmeter.

I forgot to mention the previous owner installed a Dakota Digital Dash cluster, so I do not know if there was a ammeter or light on the original guage cluster.

Also, my alternator is mounted on the Driver Side.

[MARKDTN]

Originally Posted by Minkota

I forgot to mention the previous owner installed a Dakota Digital Dash cluster, so I do not know if there was a ammeter or light on the original guage cluster.

Also, my alternator is mounted on the Driver Side.

You just need to be sure to get rid of the ammeter wiring, it's probably already gone and wired as a voltmeter style with that dash.

On a 10si/12si alternator they are easy to re-clock. The alternator p/ns I gave are for 9:00 which should point the connector at the driver side.

[68 TT]

Originally Posted by MARKDTN

I would do a couple of things in your situation. I would get rid of the factory ammeter and go to a voltmeter. I would change to a CS144 (I would not use a CS130 as a paperweight). Delco #8077 pigtail is used if you have a lamp on the dash and the #8078 has a load resistor for use with no lamp to go from SI wiring to CS so you will have to do some adapting(different plug at alternator, but can use the same sense wires). Application for a 140A CS144 is '95 Buick Roadmaster. Then I would add a bigger wire from the alternator output to the battery. I might also add a junction block near the battery to power the fans and amp, that way you don't add any high loads to the original harness. While I was wiring, I would add headlight relays as well (to get brighter headlights and take load off the original switches and wiring).

If you don't want a CS144, then a 12si in either 78A or 94A. Anything bigger may have cooling issues. The 84-85 Corvettes do have a 12si that is 120A, but I would go CS144 if I wanted over 100A. 94A 12si is Delco 321-269 application '85 Riviera with 305Y, HD cooling and a/c. 78A 12si is Delco 321-244 application '85 Cutlass Supreme with 305Y. Nothing wrong with a 10si, I would just get a 12si if I was making the change since they have improvements. Don't use a 10si fan on a 12si, you have to get the 12si fan so be sure what you buy has the fan on it.

I agree, the CS130 is an overheating pile of junk that is a ticking timebomb of a roadside breakdown waiting to happen. The CS144 is a whole different animal and is a great design. I retrofit them into everything I can make them fit into. For 180-degree ears a 1996 Impala SS application is 140-amp and for serpentine accessory drives with 90-degree ears a 1999 Tahoe has a 140-amp CS144 as an option. If you can't make a CS144 fit then the 12SI is a great upgrade from the externally regulated stock part. A 1984 Z/28 with the HO 305 has a 180-degree ear 94-amp 12SI that fits great into classic muscle car brackets.

[HO455]

Originally Posted by Minkota

What is the part number or car/truck year and model so I can purchase a internally regulated alternator. I tried using the part number shown in the stickie but parts stores tell me it’s back ordered indefinitely.

Also, what would be the best amp to choose for stock factory harness with A/C, electric fans, and aftermarket lights and radio. Just don’t want to burn truck up with too high an amp output. There is a possibility of going to dual batterie in the future.

Here is a link to what I did to convert to a late model alternator it may help you. Starts at post 467.

https://67-72chevytrucks.com/vboard/...698377&page=19

[Minkota]

So after looking at the mounting bracket that is on the truck I am not sure a CS will fit. is the Bolt pattern / spacing the same for the SI as what I currently have installed?

[MARKDTN]

Looks like you have a long water pump and later accessories with aftermarket upper alternator bracket? You may have to modify the upper bracket, but the bottom would bolt right in. When I did mine (in an '83, so RH side) I used mid-80s style crank and water pump pulleys that had a serpentine style for just the alternator, it has v-belts for a/c and p/s.

[Minkota]

Originally Posted by MARKDTN

Looks like you have a long water pump and later accessories with aftermarket upper alternator bracket?

This was all on the truck when I purchased it. Does the 10SI or 12SI have the same bolt pattern as the 10DN that I currently have installed. or will they require modifications as well?

[MARKDTN]

Originally Posted by Minkota

This was all on the truck when I purchased it. Does the 10SI or 12SI have the same bolt pattern as the 10DN that I currently have installed. or will they require modifications as well?

10si, 12si, and 10dn are all dimensionally the same as far as mounting.

[RichardJ]

All Alternators drop off at lower rpm. If it's holding close to 13.0 at idle with AC and lights on, you'll be fine.

[Steeveedee]

OK, at the battery. Were the lights and AC on?

The 13.5V is no load except the ignition- it has to be running, of course.

[Minkota]

Originally Posted by Steeveedee

OK, at the battery. Were the lights and AC on?

The 13.5V is no load except the ignition- it has to be running, of course.

That was with nothing but the truck running. No lights ac or even radio

[Steeveedee]

OK, if the battery stays charged I guess it's alright. I just remember from my mechanic days that 13.5V was the minimum to charge a battery on vehicles.

[BigBird05]

That number will change a little with ideal speed. If it is real slow. I didn't know that alternators had a use by date. LOL.

[RichardJ]

>>"flash the field"<<

An interesting term to use when you are talking about an AC Alternator.
If we were talking about a DC Generator that term would make more sense. When discussing a DC Generator, someone will always mention Polarizing the Generator.

In the first image below there are Iron Pole Pieces used in DC generators, The Field Windings are wrapped around these Pole Pieces.
These Iron Pole Pieces retain a great deal of magnetism. The Polarity of the magnetism retained in these pole pieces is crucial to the correct operation of a DC Generator.
When working on a DC Generator, it is common for the polarity of the residual magnetism to be reversed.

It is then very important to correctly align the magnetic polarity of the pole pieces, with the Polarization procedure.

AC Alternators do retain some residual magnetism, but the polarity is not an issue.

In the second image, the ignition switch connects 12V from the battery, through the voltage regulator, directly to the field winding. Full Field magnetism is generated and current begins to flow in the Stator Windings. This ignition circuit is called a Exciter Circuit.

Full Field magnetism is generated the moment the key is turned ON and also at idle. Field magnetism is reduced by the voltage regulator, as max voltage is reached.

[RichardJ]

>>The theory behind this is a perfect wire with perfect connections will not drop voltage so the meter will read zero volts.<<

All copper wire has resistance to electrical flow. The fatter the wire, the less resistance, the lower the voltage drop from one-end-to-the-other.

Chevy relies on that voltage drop on the wire between the Alt and the Battery. That is the basis of the design of the Ammeter circuit.
The greater the Alternator output, the greater the Voltage Drop on that wire, the greater the Ammeter indication.

The type of Ammeter used in these trucks must have an External SHUNT.
In this case the Charging wire serves doubly duty and is also the Shunt Wire for the Ammeter.

Other Ammeters contain an Internal Shunt. This '67-72 Chevy Ammeter does not.

[HO455]

Originally Posted by RichardJ

>>The theory behind this is a perfect wire with perfect connections will not drop voltage so the meter will read zero volts.<<

All copper wire has resistance to electrical flow. The fatter the wire, the less resistance, the lower the voltage drop from one-end-to-the-other.

Chevy relies on that voltage drop on the wire between the Alt and the Battery. That is the basis of the design of the Ammeter circuit.
The greater the Alternator output, the greater the Voltage Drop on that wire, the greater the Ammeter indication.

The type of Ammeter used in these trucks must have an External SHUNT.
In this case the Charging wire serves doubly duty and is also the Shunt Wire for the Ammeter.

Other Ammeters contain an Internal Shunt. This '67-72 Chevy Ammeter does not.

And thanks for adding clarity to the charging circuit operation.
What would you expect the voltage drop on the Shunt wire to be on a stock system at idle with all the switchable loads turned off (i.e. wipers or headlights)?

Hopefully the OP will be able get things back to normal.

[Minkota]

Originally Posted by HO455

Hopefully the OP will be able get things back to normal.

I was able to get it to charge at an idle by bumping up the idle by about 150rpm. Seems to be working fine now when idling at around 850-900 rpm.

[HO455]

That is good to hear. Congradulations!