TomP

Hi everyone, I tried a search, but couldn't find much rebuilding info- anyway, P.B just denied my lifetime warranty alternator (bearing is fried up just like the others- yes, even though it was grinding, they insisted on putting it onto the test machine! You should've heard it squeal.). Now that I think about it, that's a good thing they denied my warranty, because that was my last connection to that store. (I stopped putting up with that brand years ago when Autozone moved into the neighborhood- now I never have to go back to that other brand store.)

Anyway: Now I'm thinking of just rebuilding it myself for kicks, assuming they didn't tear up the stator/shaft running it on that alternator test bench of theirs. I've got some questions though if someone can please help?

1. I'm not sure what's in my hands now to rebuild! I don't have the CS130, I have an SI-series (that much I'm sure of) with the two-wire connector. According to the parts houses online, my 1986 2.8 V6 with A/C and Heated Back Window gets a 108 amp alternator. This alternator (in my hands now) has six square cooling vents in the back, which I think means its a 12si. However, the fan is the "old style" steel, not the plastic paddle wheel, and there's no groove on the outside/front of the case (I thought all 12si's had the groove).

On Autozone's site, the Lester number is 7897-6-6, and, according to my receipts, this was the first and second P.B alternator I had- and those had a paddle-wheel-style fan. But the third replacement alternator- which is this one with the old-style fan (failed just like the others for bad bearing!)- on the receipt it shows a new number, 7290-12. When I got this alternator, I had to undo the case halves and spin the back to get my connector to line up properly. I searched Google, but the only reference I could find for Lester # 7290 was a 108A stator for a 15si! But this case's vents look like a 12si? Or would a 15si/108A stator fit into a 12si? (108 seems like a strange # to me, why not 105, or 110?)

Finally, at ACDelco.com, my alternator comes up as part 334-2186 or 19135744, which is described as a 17si. A 17si?? Not much is said about 17si online, but I hear it's bigger than a 12si? So how did it fit? (Does anywhere list case dimensions?)

Any idea what I have?

2. How can I even find out, when I tear this thing apart, the real amperage of this thing? Will "108 amp" be stamped somewhere on the stator? Or is there something else I can check?

3. When I look at rebuild kits, two problems: They're all marked for lesser amperage (like 97A or 66A, not my 108A), and they're all specified differently for 10si/12si/15si (haven't seen a 17si kit). I assume that means the electrical parts (rectifier, trio, etc) won't work with my 108A winding? Are the bearings different sizes too?

4. Is it best (and I'm thinking this way too) to just trade this one in for scrap metal and just get a new CS130? I see alternator conversion kits out there that are meant to do this (12si to CS130). One issue is that my '86 V6 has some strange pulley setup; the alternator has a 4-rib serpentine, but v-belts run the power steering & a/c; I've always had to change pulleys. Will a CS130 take the pulley from my 12si? (or 10si or 15si or whatever it is that i have)? Oh and why aren't CS130's rebuildable, and how could I "prove" that a CS130 is the amperage it says it is? [edit] One more thing to add- I don't have serpentine; I use three belts. Even though the alternator uses a 4-rib belt, it gets tensioned by loosening the pivot & anchor bolts and using a crowbar. Will a CS130 work on non-serpentine?

Thanks everyone! Sorry this was long but I have a lot of questions! I know it might be more economical just to buy one that's already rebuilt, but I'd like to give it a shot if nothing more for the educational aspect.

Apeiron

If it's a typical rebuilt alternator, you have no idea what it could be, regardless of anything on the outside. In the factory, they just disassemble the cores, toss the parts into big bins, and then pull bits out randomly when they put them back together. Any markings you find on it will be meaningless.

TomP

Apeiron, how's it goin! Think there's anything inside that would tell me? Like a stamping on the stator, or a resistance that I can measure, or even measuring the case size?

8t2 z-chev

108a 17si sounds right-that is what i found on an '86
camaro S/C with a 2.8 Stamped on the front of the
alternator,right under the threaded hole for the upper
mounting bolt should be a part #,amp rating and a
date code.The 17si is almost the same as the 15si and
is indeed larger than a 10/12 si(earlier cs 144s are also
the same size as a 15/17 si)
15/17 si are very reliable,but like all "si" series have a
weakness in that the terminals that bolt on to the
rectifier are just crimped on to the stator wires and a
bad connection can develop there(look for signs of
heating) soldering new terminals onto the stator
wires is the fix for that problem

Apeiron

Pura vida, mae. There are probably markings, but who knows whose parts they'd be. You can build a complete "GM" alternator entirely out of aftermarket parts.

The 17si has the same 6.6" mounting holes, so it may still fit in place of a 10si or 12si.

What does your case look like?

10si


12si


15si


17si


17si 120A

Drew

iTrader: (58)

They're all rebuildable, the issue is that most people don't have the tools necessary to test modern internals.

If it's a bad bearing, check and see if the bearings are even different from one to the other and just replace the bearings.

If you want a GOOD alternator, look in the phone book and see if there's an auto electric shop nearby. A technician that works with components everyday and has to deal with turn around when his work doesn't hold up, will usually provide you a better product.

If you have all the money in the world, get a AC Delco replacement.

I wouldn't bother with upgrading to a different style alternator, it'll just open up more headaches then getting the one that belongs on your car from a reputable source.

Apeiron

Some of the mass-market rebuilds are a real crap shoot.

TomP

Cool, thanks everyone! The case pictures were great- from those pictures, 17si matches up exactly. I'm going to open it up today, so 8t2-z-chev, I'll be sure to look at those stator connections.

I wanted to rebuild it myself, especially because the few shops I knew of all retired and closed up! I figured it was better to try it myself then to gamble on a new shop. But I guess it'll depend on if I can find any 17si rebuild kits.

I'm surprised though that an upgrade to an improved model isn't a good idea? One thing I did notice was that nobody seems to put a rear support on their alternator conversions; my current bracket does have a hole thru it for a rear bolt. Isn't a rear support needed to prevent the case from cracking?

Apeiron

Even if you can't find a complete kit, you could just get new bearings.

I don't know that there'd be that much load on the body that cracking the case would be an issue. The mounting ears are up front where the side load of the belt is placed.

TomP

OK so I popped it open, the fan was really stuck on the front (had to hold the fan still while tapping the rotor with a hammer). The stator terminals were ok- they were actually soldered through the crimp connectors. Front bearing is ruined, the rotor flops around on it. I didn't press it out yet b/c I'm still not sure what I'm going to do (do it myself, have someone else do it, buy an Autozone one, or upgrade to different model).

I'm starting to think though that just becuase I "could" rebuild it doesn't mean that I "should. I like the autozone approach b/c I know they're always around if the unit fails during a road trip. Local rebuilder will probably do a better job- but if I get stranded 100's of miles away, I'll be buying one from another store. Unless I carry a rebuild kit and a press in the car! Or, maybe, if it did fail on a road trip, that's when I buy into an upgrade.

CS130 vs CS144, are they the same case size? I hear people say the CS144 is more reliable because it has a larger bearing that stays cool; does it make sense to upgrade to CS130 or just go right to CS144? (87-up v6's had CS130- same "start year" of serpentine belts). I hear I need to put an extra resistor on the CS144 though (I guess my warning lamp won't count anymore).

8t2 z-chev

cs 130 and cs 144 are not the same case size-early
cs 144 is the exact same size and mounting as a 17si,
the early style cs 144 was used from mid-1986 up to
around 1995 and IIRC,has 108 and 120a versions.
The later cs144 came out around 1990 and i beleve
includes a 140a version-though the case castings are
bulkier on the later version,i think the mounting
dimensions are basicly the same as the earlier version.
BTW LT-1 camaro is one app that uses the cs 144;
'93 early version,'94-97 later version.

tr6guy

TomP - I live in Edison,NJ. there is a great alternator rebuild shop in the Avenel section of Woodbridge Township - right on St. George Ave - almost directly across from Lee's autobody Shop. It's a real hole in the wall, but they've been very helpful in the past. The name of the place escapes me ... but its a real good place for parts and information.

TomP

Great, thanks guys! tr6guy thanks for the tip, I'll give that road a drive this weekend to see what I can find; if you remember the name let me know!

8t2, that's awesome to know the cs144 has the same mounting dimensions! That'd mean I could still use the bolt for the back-support (goes right to the case). And these are supposed to last longer than the si-series right? I found some pictures, is this the difference you mean?

120 amp picture: http://www.rockauto.com/catalog/moreinfo.php?pk=1000250
140 amp picture: http://www.rockauto.com/catalog/moreinfo.php?pk=1001785

Those pictures are from looking up a 1994 Z28, they have both a 120 and 140 listed. Another company seems to say a "threaded stud" is the 140 amp, and "square terminal" is the 120 amp. I did more searching on Autozone's website, looks like the 89 Turbo T/A had a cs144 too- looks the same as the other 120 amp but has the connector at a different clock position.

Maybe this weekend I'll visit some junkyard and see if I can find a cs144...

Is the cs144 the same as my si-series, where I can just unbolt the back and spin it around to put the connector at a different clock position? Or do I have to find an alternator with the exact clock position I need?

Apeiron

You can reclock a CS144, same as the SI series.

Lucid

iTrader: (4)

You can rebuild your own SI series alternator, and you can be proud of your work after you rebuild it correctly. You have to pay attention to the way you take it apart and put it back together and where to put the insulated/non insulated screws, etc.

IMO, the CS144 is a much better alternator. I have 140amp units in both my third gens from a 1996 5.7L Caprice model. I wouldnt go back to an SI alternator after seeing what these units can do.

If you are going to expend the energy to do a conversion, skip the CS-130 and go straight for the big dog, the CS144.

You need to slip a straight pin into the brush holder to keep the brushes in place if you decide to reclock it. Also, you can buy the conversion harness from an alternator shop or online.

CS144 thread:
https://www.thirdgen.org/forums/elec...ed-up-alt.html

TomP

Lucid, thanks for the info, especially about the CS144 info. I decided yesterday though that it's too cold around here to crawl junkyards or decide which rebuild shop to go to, so I'm just going to go to Autozone and get their 17si replacement alternator (DL7897-6-6) so the car gets running again. Then when it's warm out I'll do the CS144 upgrade.

I checked out that thread (lots of great info in there!) but maybe missed something- you said your '86 originally did, or didn't come with, a rear bracket, for the 17si? Did you use the junkyard bracket you got with the CS144?

Oh and I saw where you said the junkyard CS144 died so you got a replacement from Autozone- how did that AZ one hold up? (I see the message is 4 years old now ) Everywhere I go (even my out-of-state vacation spots) there are Autozones nearby if it fails under warranty. And I like your idea of keeping the old 17si as a spare, maybe I'll throw it in the backseat when I go on vacation!

Lucid

iTrader: (4)

TomP,

I had to go to the junkyard and look through parts cars to find a bracket that would work with the CS144. I didn't like how our stock one just would hang there and not be connected. I pulled a couple off a mid eighties set of Caprices and used them on both my cars. It really looks stock after you get it buttoned up.

I thought the junkyard CS144 broke on me but it didnt, its currently running in my 87 IROC. The autozone alternator is still running fine in my 86, and hasnt been changed yet.

On the 86, the stock mounting configuration worked fine. On the 87, since the car came with the dinky (physically smaller) CS130 alternator, I had to replace the top bracket with an older model TPI bracket.

I am hanging on to the stock brackets in case I ever need to put stock stuff back in, although I cant imagine why i would do that.

BTW, I bought my alternator from a late model junkyard where they pull the part for you. I think I paid something like $40 for it and they warrantied it for 30-90 days. I took it to autozone right after I bought it and they tested it for free.

Check with a local alternator shop and see if they stock the conversion harness or make your own ahead of time.

If you are going to buy a rebuild, go on Advances website and the year make and model of the car you are going to buy it from and it will tell you the clocking right on the website.

TomP

Cool, thanks for the info Lucid! I'll chase down my cs144 upgrade next year (when it's warmer) and that'll come in handy.

For now I just went to Autozone and got the DL7897-6-6, it's definitely a 17si (thanks to Apeiron's picture list) and what do you know, it actually came with a new pulley for me! My v6 has some strange pulley, a 4-rib 2 inch, and on every alternator I've ever changed (I've been through many of them), I've had to change the pulley. And with that Lester number, it should've had a -6 rib pulley. But no pulley change for me this time, it came with a 4-rib one! Hey that's really exciting stuff. The guy at Autozone tested it for me before I left the store too. So I charged the battery, stuck it in the car with a new belt, and went for a ride!

I'll post back on this thread when I do the CS144. I like the idea that it should be running cooler than the 17si; every alternator I've gotten has failed because of the bearing getting hot.