NO. All regulator power is shut off with the ignition switch, and it gets power off the same wire that supplies the ignition. So if the regulator was still powered, the engine would still run
The one off the 87 will work fine.
You need to find out whats?? going on, IE the root of the problem. Don't start buying and throwing parts at it
1 Charge the battery and have it LOAD TESTED. A load tester is a carbon pile resistor that puts a heavy load on the battery and someone who knows how to use it. Example:
http://www.ntxtools.com/Merchant/graphics/00000001/atm-sb5-2.gif
2 With a known good, charged battery in the car, determine if the charging system can and does work, and if not, why. You'll need a bag of clip leads from Radio Shack, an inexpensive multimeter (20-25 bucks at any Radio Shack, Sears or auto parts store) and a 12V test lamp. All these are things "you should have" to work on these old girls
3 With the battery up, the car running at an RPM to simulate "medium cruise" check the battery voltage carefully. With the engine and regulator warm (it's temp sensitive) battery voltage should be close to 13.8--14.2v, and in no case below 13.5 nor above 14.5
If this is so, maybe the battery was the problem. Maybe you have an intermittend
You might check the belt(s) for condition and tightness
You might pull the alternator and see if the brushes are free, and not sticking because of mud, grease. How worn are the brushes?
4 If voltage is low below 13v, next determine if it's actually the regulator, the alternator or the wiring, First identify and disconnect the GREEN field wire, and hook a clip lead from the exposed alternator field terminal to ground Run the engine, watch the ammeter, and see if it charges. As you increase RPM, it should "bury" the gauge needle at charge.
If this is so, you have a wiring problem in the field/ regulator circuit, or a bad regulator
Hook the green wire back up. Go up to the regulator and disconnect it. Devise a way to jumper the two connector terminals. Machine screws and a clip lead should work.
Next go back to the alternator (your green wire should be hooked back up) and now unhook the BLUE field wire and ground that alternator field terminal
AGAIN run the engine and check for charge. If it does, the wiring is OK. REPLACE the regulator with a good quality Standard (Blue Streak) or NAPA Echlin. (Or use your 87)
If it does NOT charge in EITHER of the above tests, you probably have a bad alternator, or problems in the alternator output wiring, which goes through the bulkhead through the ammeter, and back out the bulkhead to the battery THESE CONNECTIONS can give trouble and are the reason for the bypass yo have heard about.
Read this excellent article on the hows and whys:
http://www.madelectrical.com/electricaltech/amp-gauges.shtml
So another test you can make to see if the alternator output wiring is to blame, is bypass the regulator up in the first test, then measure battery voltage compared to voltage at the alternator output stud. If this is more than 1-2 volts, depending on whether it's charging hard or not, you have a voltage drop problem as in the MAD article.
Post back here as you go, and wel'll try'n steer you through it.
