Shedluv

I have done a search and have read many posts regarding the Delco alt mod. There was never a complete "how to" and I just wanted to make sure that I got everything out of the posts correctly.

I have a 1982 928 auto with the ribbed belt.

You need a Delco CS130 alt -- use 1988 Camaro V6 with A/C for vehicle at auto parts store.

The top bolt goes through the smooth hole on the alternator. Because the tab on the Paris-Rhone is longer than the Delco, you need 5mm of spacers (washers) between the bolt head and the front of the alternator so that it will tighten down properly (the bolt is not threaded all the way).

The bolt on the slider on the bottom of the alternator attaches to the small tab on the Delco. Since this is a long bolt and the tab on the Delco is very short (1/2" ish), you have to have the bolt threaded all the way up with a tap and die set (any other options?). Are the existing threads on the bolt the same size as those on the Delco small tab?

To clear the engine mounting tab on the adjustment arm, you need to make a small notch near the top of the arm so that the adjustment arm can sit at a more horizontal angle.

Also, as an option, you could go to a 1" shorter belt (34" instead of 35") so that the alternator doesn't have to be tilted out so far to get the belt tight.

Wiring is B+ to big lug. Get pigtail connector and put L to exciter wire (small green/blue wire attached to factory alternator). Also may need to put S to B+ lug (larger wire in connector).

The pulley could be swapped, but does not need to if you have the ribbed belt as they are the same size (or really close) to the factory pulley.

Before I start, I just wanted to make sure all of this is correct. I plan on starting this in the next couple of days and wanted to verify all of the information. It also might be good to put it all in one place so someone else searching like me wouldn't have to search through many posts.

hacker-pschorr

Lawrence, Kansas??? Sweet, my old stomping ground.

Um, alternator upgrade. On my short list of things to do this summer. Thanks for the write-up. Maybe I'll move this up the list for a June completion date.

Did you buy the pigtail from the same place as the alternator?

rjm65

On my 79, the stock size belt was too long after the Delco alt swap. I went with a shorter belt and discovered that I wouldn't have needed to notch the adjustment arm had I used the shorter v-belt to begin with.

In my case, the notch was only needed because the arm hit the block as it pivoted when you tensioned the longer belt. The shorter belt didn't pivot the arm as much, hence no notch required.

Again, my setup is v-belt, but can't see why this would be any different with ribbed belt.

Sailmed

Looks like you've got it!
It is a rather quick and simple task.
I've done it on 4 or 5 of my cars.
Good luck, and welcome to the club!

Shedluv

I haven't done this yet, but just did a lot of reading from different posts to make sure this was all that I needed to know before I did this. I know that they sell the pigtail at NAPA and O'Reilly's, not sure about anywhere else, most alternator shops should have them and there's always Painless wiring kits as well.


Anyone else verify that I have all of the correct information there, specifically the threads on the adjuster bolt to the small tab on the CS130? Same size, just thread all the way up the bolt? Thanks.

Landseer

Its not a 130Amp unit, that reference came from somebody trying to shoehorn the next sized unit into the car, as some new amps and accessories tend to draw a lot of power.

I think its 105 Amps or 115Amps. You need the alternator and the pigtail. Only one wire of the pigtail is utilized, its connected to the small harness wire, the blue exciter wire. The wire labled "L" on the pigtail is the one you should utilize.

The other two wires from the Porsche harness are attached to the hot lug on the back of the alternator.

You will probably need to add three flatwashers as spacers between the frontmost engine mount and the frontmost part of the alternator. The long mounting pivot bolt passes thru them.

For the pulley, not exactly sure on your year. I've installed two on my 84 cars and used the pulleys that came with the alternators, but choose a slightly shoretr belt.
I eliminated the tensioner bolt and used a simple thru-bolt. Used a tire iron to pry it snug, then tightened the bolt, just like GM underengineered it.

Shedluv

CS130 is the GM model number of the alt, but I know it is a 100ish amp alternator. The CS130D is just a more robust unit with slightly different mounting style. I read all about that guy's trouble as I have dead CS130D sitting here that came off of my 98 S10 and was hoping to just rebuild it and put it on, but it doesn't put out enough power at idle.

Guess I could just replace the tensioner with a bolt as you have. I'm gonna have to call around to a metal shop and see how much it would be to have the stock bolt re-threaded as I like the easy adjustment. Got tons of woodworking tools here but no tap and die set for that.

Landseer

I tried carefully running a lubricated die down the tensioner bolt. I think the non-threaded section of the bolt was too large a diameter for the die, so the bolt broke.

6mil928

I did it and all your info looked correct Landseer and Firemed are the Delco guru's. If they say it's good it's good. FWIW the delco did not fix my lack of charge at idle.

LT Texan

just use a bolt about 2" long and don't use the tightening mechanism on the original. the delco thread is metric too.

had to notch the arm no matter. also has to file off a corner at the block end bolt hole.
I had to go shorter. But I used the v pulley off the old alternator, so different application.


I didn't need to hook up the second wire from the pigtail.



13.8v at idle with electric fan running!!!

SharkSkin

Charge at idle is the big challenge. Porsche decided to use a small crank pulley, so the alternator spins slower than it would in another car. That's one reason the Porsche alternators are $$$ -- they are designed to charge at low speeds. Great for reducing parasitic HP loss -- not so good when you want to put a generic alternator in.

6mil928

Yep I've considered a smaller pully.

SharkSkin

Yes, but you can only go so far -- IIRC 1-7/8" with the ribbed, 2" with the V-pulley.

Shedluv

After running the car for over a year with a non-functioning alternator and having a 2nd huge marine battery laying in the back for back up, charging anything at all is helpful. When you are running on battery alone, your "going for a drive" trips become very short. Just trying to get it back to being able to either be a daily summer driver or a once/twice a week fun car.