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Discussion Starter · #1 ·
I seem to get drawin into a lot of alternator issues and alternator upgrade discussions. Well, one of the cars I'm caring for now needs an upgraded alternator. I saw this coming, but the owner wanted to adress other issues first and let the alternator ride until later. This past Sunday, "Later" arrived. So, I'm taking this opportunity to share with the community here what's involved in an upgrade from a "one wire" GM alternator to a newer technology alternator that is a stock "3 wire" design.

Background.

The engine is a straight 6, 250CID engine from a 1978 car. Not sure if it was originally in a Nova, a Camaro or some other car. It has an upgraded head (big valves, lump kit), and the Clifford Pefrormance single 2 barrel intake with a Weber 38/38DGES and Clifford Performance Headers. It also has the 1975 6 cylinder HEI distributor (without the "coil in cap") and a MSD Blaster SS coil.

The car is an interesting Classic/Antique Limousine. It's A 1965 Vanden Plas long wheelbase Limousine chassis with Rolls Royce coachwork. The original Austin 4 Liter drive train has been replaced long ago with the 250CID straight six Chevrolet engine and TH350 transmission. It's not what most people think of as a "hot rod," but the engine swap and upgrades make it at least a little hotrod-ish.

The alternator situation:

This car has electric fans, two air conditioning systems, two stereo systems (one of them pretty heavy duty for the back seat passengers), and lots of other electrical additions. The alternator that was on the engine was a 10SI single wire alternator. I'm not sure if it was the stock 63A rating, or the "aftermarket improved" 100A version from the manufacturer on the label. No part number was on the unit, just a company name and a phone number. Since the failure is entirely due to abuse, I'm not going to drag them through the mud here. The failure isn't on their product, it's on deliberate misuse of their product.

It's never had enough alternator current at idle to maintain voltage with both AC units running, and when you add stereo systems running, lights running, and the electric fans running constantly, it just goes downhill quickly. It's always been overloaded at idle. It barely could charge running down the road (2000 RPMs+). This past weekend, the alternator finally burned out and gave up.

This car has a job this coming weekend (Friday night), so I have to get this fixed in a hurry. I should analyze the loads and get an alternator that's big enough, then deal with pulley issues (we have v belts on this engine) and any other wiring issues to get the proper alternator running.

Right now there's not time for that. We're going to start off with a 105A CS-130 unit and see if that gets us through a few jobs and analyze performance to see if it's adequate. If it's not adequate, then we'll look at even higher amperage CS-144 or AD-244 units (with pulley swaps and other issues to deal with then) for further upgrades and do that when we can schedule some down time for this car.

I remove the 10SI and took it to my FLAPS (the local O'Reilly Auto Parts). They spun it up on their tester and pronounced it dead. I explained that even when it was "operating as designed," it wasn't nearly "good enough" for the loads we had on it. An exact replacement wasn't going to help me at all. I proceed to tell the guy I needed:

  • 1 Alternator for a 1986 Camaro with a 2.5L 4 cylinder engine (CS-130 design, 105A, with a V belt pulley),
  • 1 wiring pigtail for that alternator (AC Delco PT2297 was not available, but they had Standard Motor Products S552 available)
  • 1 Dorman panel mounted indicator light (for a light in the dash as right now we have no working alternator light, adding an element of surprise to this current failure)
For the project I'll also need wiring, brown and orange wire in 16AWG, red wire in 12AWG, and a couple of inline fuse holders for the orange and red wires. I already have a charge wire that's 4AWG in place (I knew an alternator upgrade was coming and put this in when we did the intake/head/headers).

Parts will arrive Wednesday (9/14/22), and I'll be doing the work then and taking a lot of pix. I may also give more explanation as to why the CS-130 is a better choice (hopefully adequate, but way better than the SI we had) for this car, and why it's a good choice with electric fans and other increased electrical loads in an older car.
 

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Well, well..............normally it's us Brits wanting American cars,.......... rarely the other way round!

The original car's 4 litre engine was actually a lorry engine that was dropped in...........so hardly a tyre smoker!
 

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The CS-130 is a great upgrade. Lots of writeups on whats needed (don't install the diode backwards).

For what your describing you may look at installing a second battery and/or a capacitor depending on the stereo size.

You could even install "invisible" wireless phone charging hidden under/inside the coachwork.
 

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Discussion Starter · #4 ·
Well, well..............normally it's us Brits wanting American cars,.......... rarely the other way round!

The original car's 4 litre engine was actually a lorry engine that was dropped in...........so hardly a tyre smoker!
That's interesting. I confess I don't know much about the original engines in these cars. We have a 1965 (this one), and a 1961 model with a 4.3L GM V6/4L60E automatic with overdrive from a 2000 Chevy Blazer.

The CS-130 is a great upgrade. Lots of writeups on whats needed (don't install the diode backwards).

For what your describing you may look at installing a second battery and/or a capacitor depending on the stereo size.

You could even install "invisible" wireless phone charging hidden under/inside the coachwork.
One one of the next major breaks for this car, I'm hoping to do some wiring upgrades/clean up. Maybe reclaim and sell some of the original parts, and a second battery in the trunk is definitely on my "to do" list. Not just for the stereo, but the second air conditioning unit is back there, and believe it or not, the AC condenser (one condenser for both systems) with condenser fans are under the trunk floor.

Unfortunately, we get a summer break (most of July into early August) and a winter break (December/January), and I also have other work to do on this one. I've got to do a short block (new "towing application" camshaft plus freshening up everything), possibly with a fresher TH350 transmission. If the short block isn't ready (camshaft just arrived, and I don't have a commitment from the engine builder), I'll definitely get to the wiring.

I'm actually going to be embarrassed by some of the wiring I'll have in the pics for this project. Everyone should bear in mind, I didn't wire this thing before, I inherited most of the mess.
 

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Discussion Starter · #6 ·
Pics from yesterday. I'll be finishing this later today, with more pics.










The pics have information in the full descriptions in the gallery. Ill be back later today with more details.
 

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Discussion Starter · #7 ·
This job is finished. I did take pics. But my phone is charging now.

I'll be back later this weekend with more pics and full write up. Also with performance numbers from the test sheet that came with the new alternator, and an explanation of what makes this a better alternator than any 10SI or 12SI alternator.
 

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Discussion Starter · #9 ·
Kinda wonder if a dual alternator setup may be an idea? Would be a custom mount design on that engine
We will be changing out the bracketry on this engine soon. It's not out of the question that we might go with dual alternators, and dual batteries.
FLAPS??? Something - Auto Parts Store?
FLAPS = Friendly Local Auto Parts Store. Whether it's a local independent (possiblly a franchisee of a larger brand) or a local store in a large chain.
 

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Discussion Starter · #10 · (Edited)
Coming back to this after a very busy week or so.

A quick post today, first, to explain why the CS130 is a better choice than a 10SI, even a "high output" 10SI.

The big issue is idle current. When the 10SI was designed, there were no electric radiator fans installed at the factory, and about the only electric power needed to run the car was power for the coil. Idle performance from the alternator wasn't an issue. There are even GM technical bulletins from that era explaining that if your headlights dim when you stop at night, that's "normal."

Then came the 1980s, front wheel drive cars and electric radiator fans. Electric radiator fans have two issues. First, they tend to draw a lot of current (20 amps each for dual fans, often 30 amps or more for a big OE single electric fan). Second, and more importantly, they tend to turn on when the engine is idling and turn off when the RPMs are higher driving down the road. That's exactly the kind of load that an SI series alternator doesn't handle well at all. Not only do the headlights dim, the radiator fan slows down, the engine heats up, and the alternator itself gets much hotter from being overloaded at idle.

So that was the big reason for the development of the CS-130 alternators. They were specifically designed to address idle output issues presented by electric fans, (as well as added total capacity for electric fuel pumps and fuel injection systems).

Putting numbers to it, most SI alternators produce less than half their rated current at idle.63A units generally make 25A to 30A at idle. Just recently someone here reported seeing 41A from a "high output" 100A 10SI. Some I've seen (working ones, not failed ones) were just over a third of their rated current at idle. The CS-130 series tends to be around 2/3rds of the rated current at idle, sometimes a little higher than that.

Here's the performance test report that was included with the 105 Amp CS-130 that I installed in this car:

Font Parallel Pattern Rectangle Document


The engine in this car idles between 700RPM and 750 RPM, and the pulley ratio is about 3:1. That means the alternator is spinning 2100 RPM to 2250 RPM at idle, and we're now getting somewhere between 70A and 90A from the alternator at idle, probably around 80A if I had to guess. That's more current from this one at idle than a stock 63A 10SI puts out at full output, and about twice what some 100A 10SI units put out at idle.

I'll be back in a day or two with the wiring diagram I built from, as well as some pics of the final wiring and reports of the actual system voltages with and without various loads.
 
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