From other threads I've started, I figure I might as well start one for this. Dialup folks, I'm sorry, you'll have to wait for the pics to load, they are big.
My alternator (for various reasons) is dead. Easy never being the route I choose, instead of replacing the 78 amp 12SI with another, I am going to attempt to go to a 105 amp CS130. Of course, this can not happen when I have the time to wait on the recommended parts, I have "special ordered" this one from Schucks (Checker or Kragen depending on part of country) http://www.partsamerica.com/Product...TR&MfrPartNumber=A1341511&PartType=11&PTSet=A ($89.99) it is an autolite A1341511, with a lifetime warranty. Supposedly for an '87 Camaro, we shall see.
Part number not "correct" because the alternator is clocked wrong to accept the lower alternator bolt spacer that bolts to the case. Unbolt the three case bolts (1/4" socket works), separate the case halves just enough to rotate to where you need it, and bolt back together. You'll need to clearance the alternator spacer a fair bit as it hits the alternator case. I had to use a thick washer between the case and the bracket, bracket is just a hair off in that dimension.
In my case I've got a bunch of things going against this swap, so much of this will not apply to anyone considering a similar swap. However, the wiring and overall fitment should help some.
My drivetrain is a conglomeration from various vehicles. Pertinent in this case is the TPI, as it affects upper alternator bracket/fitment, and the 1985 Monte SS donor pulleys, etc., as that affects belts...it's the semi-serpentine 5 groove setup....serpentine for alternator, water pump, and crank, power steering on a V-belt. I am most worried about the pulley alignment...it's already not perfect, since the upper alternator bracket is for a CS130, with a 12SI forced into it.
Reason I'm going with the CS130 vs. 144 or other is because that's what my TPI came with, so it SHOULD fit the upper bracket. Not to mention that it's also in my Camaro manuals, so I have the right info for later.
For wiring, the 12SI (at least mine) has a total of 3 wires. 2 on a single plug, and one to the stud on the back of the alternator.
Easy stuff: CS130 requires two wires. One for the battery, one for a battery light, or something to provide resistance on that terminal...easiest way is with an adapter plug. Adapter plug connects your stock 2 wire 10/12SI connector (flat plug) to the CS-style alternator plug, which is 4 wire, of which 4, only one is necessary.
Adapter plug is available, without a charge light (as in my case) you need an adapter harness with a resistor built in. This is Echlin Part number (Napa) EC82. Apparently AC Delco, Autozone, nor Checker/Schucks/Kragen can cross reference this part. The part numbers normally mentioned Delco P/N 8078 General Motors P/N12102921 appear to no longer be valid, none of the above listed could cross them, they don't show up on AC Delco.com, gmpartsdirect.com, nor can my local GM parts counter find or cross them. Carquest was, and they put one aside for me. I'll post up what number they are using, when I verify it is the correct item tonight. Carquest S792 "connector".
One thing that I see being mentioned in some articles and the service manual is how to disconnect and reconnect the alternator correctly. I am going to have to remind myself of this when doing so.
Articles below are what got me started:
http://oljeep.com/gw/alt/Alternator_Theory.html#Section_3 (pretty commonly mirrored, same dates on all that I've seen)
http://www.novaresource.org/alternator.htm Nice due to the pictures of the install.
http://www.ifsja.org/forums/vb/showthread.php?t=3092 CS144 install, but a fair bit of good info nonetheless.
http://cache.search.yahoo-ht2.akadns.net/search/cache?ei=UTF-8&p=12si+swap+to+cs130&fr=yfp-t-305&u=www.binderbulletin.org/forums/showthread.php%3Fp%3D514812&w=12si+swap+cs130&d=dogrAy72RF1_&icp=1&.intl=us Cached forum thread, not sure if that will link ok. I better save it, looks like the site might be dead.
All done.
Some photos here, just didn't take one of it installed. Can if requested.
http://rides.webshots.com/album/564090900QKgBCV?vhost=rides
edit:
Be careful with the adapter harnesses.
Engagement of the terminals in the adapter plug/harness listed above that mate up to the stock alternator plug are minimal at best. No time to play around with it, but looks like the adapter plug is not necessarily designed for the truck alternator plug. It locks into the adapter, but COULD, if designed a bit differently, go in another 1/4-1/2". I'm going to figure a way to make sure the connection is good before I blame the connector.
Thought I lost my alternator the 24th (I tested it three different times with multimeter while it was on the truck, 11V with the truck running at the battery and alternator) but passed the in-store test a bunch of times.
I will clarify that I've got a somewhat odd alternator plug, although it was factory from some GM product of the 80's, might have been a van. It has almost a "t-handle" that both keeps the wires from being stressed, and allows for easier grip to pull it. I'm going to try and find a "normal" plug and see if they will seat deeper, but I don't think so, since the alternators all had the same attachment method. Only way to fix this would appear to be cutting some plastic back on the adapter harness plug AND the alternator plug, both of which is going to weaken how the two connectors lock together. I'll take pics if I can.
Here are the pictures showing the adapter harness that didn't work right, the fix, and some data.
This is the adapter harness plug mated to the stock alt plug. Note that you can clearly see the blades are not going very far into the stock plug. It appears this harness is not made for these plugs, although it fits. But this is why I lost charge. The connection was intermittent. That is unacceptable. Get a stock CS alt plug from the wrecking yard, and ad the resistor yourself. It is NOT worth the harness $$ or the potential headache! I paid about $25 for this harness that isn't correct! Anybody that can cut and splice can make this themselves. If you get an adapter that looks like this, you are going to have to cut and solder anyways, why not make the thing for about $2 instead of paying someone else (too much) for the privilege of modifying something they made wrong. In the end, I ended up cutting the 12SI plug off, the adapter end off of the harness, and soldering the CS plug directly to the truck harness. It couldn't have been easier.
Here is the pinout of the CS alt plug. You only need those two wires. On my setup the red goes to red, the yellow goes to the brown. Yellow hot with the key on, red hot all the time.
Picture of the resistor in the harness. Looks to me like they heated the shrinkwrap up too much when they made it, no sign of abrasion.
I'm not that good with the meter, but I did test resistance on the yellow wire through the resistor, which will give our electrical experts enough I'm sure to recommend the right resistor. I'm pretty sure the correct resistor value is given elsewhere online (probably in the links above) though to build your own.
Here's the stock alt plug I had originally, I think I got it from a van.
My alternator (for various reasons) is dead. Easy never being the route I choose, instead of replacing the 78 amp 12SI with another, I am going to attempt to go to a 105 amp CS130. Of course, this can not happen when I have the time to wait on the recommended parts, I have "special ordered" this one from Schucks (Checker or Kragen depending on part of country) http://www.partsamerica.com/Product...TR&MfrPartNumber=A1341511&PartType=11&PTSet=A ($89.99) it is an autolite A1341511, with a lifetime warranty. Supposedly for an '87 Camaro, we shall see.
Part number not "correct" because the alternator is clocked wrong to accept the lower alternator bolt spacer that bolts to the case. Unbolt the three case bolts (1/4" socket works), separate the case halves just enough to rotate to where you need it, and bolt back together. You'll need to clearance the alternator spacer a fair bit as it hits the alternator case. I had to use a thick washer between the case and the bracket, bracket is just a hair off in that dimension.In my case I've got a bunch of things going against this swap, so much of this will not apply to anyone considering a similar swap. However, the wiring and overall fitment should help some.
My drivetrain is a conglomeration from various vehicles. Pertinent in this case is the TPI, as it affects upper alternator bracket/fitment, and the 1985 Monte SS donor pulleys, etc., as that affects belts...it's the semi-serpentine 5 groove setup....serpentine for alternator, water pump, and crank, power steering on a V-belt. I am most worried about the pulley alignment...it's already not perfect, since the upper alternator bracket is for a CS130, with a 12SI forced into it.
Reason I'm going with the CS130 vs. 144 or other is because that's what my TPI came with, so it SHOULD fit the upper bracket. Not to mention that it's also in my Camaro manuals, so I have the right info for later.
For wiring, the 12SI (at least mine) has a total of 3 wires. 2 on a single plug, and one to the stud on the back of the alternator.
Easy stuff: CS130 requires two wires. One for the battery, one for a battery light, or something to provide resistance on that terminal...easiest way is with an adapter plug. Adapter plug connects your stock 2 wire 10/12SI connector (flat plug) to the CS-style alternator plug, which is 4 wire, of which 4, only one is necessary.
Adapter plug is available, without a charge light (as in my case) you need an adapter harness with a resistor built in. This is Echlin Part number (Napa) EC82. Apparently AC Delco, Autozone, nor Checker/Schucks/Kragen can cross reference this part. The part numbers normally mentioned Delco P/N 8078 General Motors P/N12102921 appear to no longer be valid, none of the above listed could cross them, they don't show up on AC Delco.com, gmpartsdirect.com, nor can my local GM parts counter find or cross them. Carquest was, and they put one aside for me. I'll post up what number they are using, when I verify it is the correct item tonight. Carquest S792 "connector".
One thing that I see being mentioned in some articles and the service manual is how to disconnect and reconnect the alternator correctly. I am going to have to remind myself of this when doing so.
Articles below are what got me started:
http://oljeep.com/gw/alt/Alternator_Theory.html#Section_3 (pretty commonly mirrored, same dates on all that I've seen)
http://www.novaresource.org/alternator.htm Nice due to the pictures of the install.
http://www.ifsja.org/forums/vb/showthread.php?t=3092 CS144 install, but a fair bit of good info nonetheless.
http://cache.search.yahoo-ht2.akadns.net/search/cache?ei=UTF-8&p=12si+swap+to+cs130&fr=yfp-t-305&u=www.binderbulletin.org/forums/showthread.php%3Fp%3D514812&w=12si+swap+cs130&d=dogrAy72RF1_&icp=1&.intl=us Cached forum thread, not sure if that will link ok. I better save it, looks like the site might be dead.
All done.
Some photos here, just didn't take one of it installed. Can if requested.
http://rides.webshots.com/album/564090900QKgBCV?vhost=rides
edit:
Be careful with the adapter harnesses.
Engagement of the terminals in the adapter plug/harness listed above that mate up to the stock alternator plug are minimal at best. No time to play around with it, but looks like the adapter plug is not necessarily designed for the truck alternator plug. It locks into the adapter, but COULD, if designed a bit differently, go in another 1/4-1/2". I'm going to figure a way to make sure the connection is good before I blame the connector.
Thought I lost my alternator the 24th (I tested it three different times with multimeter while it was on the truck, 11V with the truck running at the battery and alternator) but passed the in-store test a bunch of times.
I will clarify that I've got a somewhat odd alternator plug, although it was factory from some GM product of the 80's, might have been a van. It has almost a "t-handle" that both keeps the wires from being stressed, and allows for easier grip to pull it. I'm going to try and find a "normal" plug and see if they will seat deeper, but I don't think so, since the alternators all had the same attachment method. Only way to fix this would appear to be cutting some plastic back on the adapter harness plug AND the alternator plug, both of which is going to weaken how the two connectors lock together. I'll take pics if I can.
Here are the pictures showing the adapter harness that didn't work right, the fix, and some data.
This is the adapter harness plug mated to the stock alt plug. Note that you can clearly see the blades are not going very far into the stock plug. It appears this harness is not made for these plugs, although it fits. But this is why I lost charge. The connection was intermittent. That is unacceptable. Get a stock CS alt plug from the wrecking yard, and ad the resistor yourself. It is NOT worth the harness $$ or the potential headache! I paid about $25 for this harness that isn't correct! Anybody that can cut and splice can make this themselves. If you get an adapter that looks like this, you are going to have to cut and solder anyways, why not make the thing for about $2 instead of paying someone else (too much) for the privilege of modifying something they made wrong. In the end, I ended up cutting the 12SI plug off, the adapter end off of the harness, and soldering the CS plug directly to the truck harness. It couldn't have been easier.
Here is the pinout of the CS alt plug. You only need those two wires. On my setup the red goes to red, the yellow goes to the brown. Yellow hot with the key on, red hot all the time.
Picture of the resistor in the harness. Looks to me like they heated the shrinkwrap up too much when they made it, no sign of abrasion.
I'm not that good with the meter, but I did test resistance on the yellow wire through the resistor, which will give our electrical experts enough I'm sure to recommend the right resistor. I'm pretty sure the correct resistor value is given elsewhere online (probably in the links above) though to build your own.
Here's the stock alt plug I had originally, I think I got it from a van.
Last edited:
