srholt45@gmail.com

Hi Guys,
After two new voltage regulators and alternator being checked by two different car parts stores, I still cannot get the 13.5 volts of charging Im looking for. Battery shows 12 volts, checked for continuity of wires, looked at all pigtails and still no charging. I did the screw driver test on back of alternator and it does have a small amount of magnetism. Seems weak compared to alternater on a jeep. Im stumped. Any advice would be greatly appreciated.

Thanks
Solon

srholt45@gmail.com

Forgot to mention the car is a 1972 cutlass with a 350 engine

Don R.

Remove, clean, and reinstall battery cables (both ends) and alternator connections, be sure you have good tight metal-to-metal ground connections. Inspect wiring and connectors at regulator. Have you had your battery checked?

droldsmorland

First check and clean all grounds and positive connections. This includes the battery cables, alternator and starter wires too. There needs to be a good ground path from the battery and from the engine block to the frame and the body. Check for continuity and opens in the battery, alternator and VR wires with an Ohm meter. Now load test the battery. Fail... replace battery. Pass... re-charge the battery, then disconnect the charger, verify that the voltage on the battery is 13.2 Volts or higher (it should read high due to the surface charge).
Now turn the headlights on for 60 seconds. Turn the lights off and check the battery, it should read 12.6 Volts or higher. Now start the car. Measure the voltage across the battery, if it is not 13.8 Volts or higher, the alternator is not working correctly. If this passes, turn the headlights on. The alternator should be able to maintain 13.5 or higher, even with the lights on and the engine at idle. If the Alternator is not passing these tests, carefully measure the voltage at the rear of the alternator, across the battery terminal and the alternator case with the engine running and the headlights on. If this voltage is within 0.1 Volts of what you were reading at the battery, then either the alternator or regulator is bad. If this voltage reads higher, you have a high resistance path between the alternator and the battery. To find what side is bad (power or ground) begin by measuring the voltage between the alternator case and the battery negative terminal. The voltage should be 0.1 Volts or less, if not, you have a bad ground. Next, check the voltage between the battery post on the alternator and the battery positive terminal. Same as before, if the voltage reading is more than 0.1 Volts, check the wiring between the alternator and the battery. Before you hook up the Volt meter, with the engine still running and the headlights on, measure the voltage from the regulator case (use one of the mounting bolts) and the battery negative. Again, the voltage should be 0.1 volts or less. If not, check the ground from the rear of the engine block that connects to the body. Finally, if the alternator failed the test, turn the engine off and attempt to rotate the alternator pulley by turning the fan. You should not be able to rotate the alternator without the engine turning as well, if not, your belt is loose or glazed and this will result in poor alternator output.

Fun71

In regards to the grounds, I seem to remember one of the bolts on my voltage regulator had a star washer between the VR case and the firewall to ensure a good ground. That may be something to check.

srholt45@gmail.com

Thank you for the replys. Some observations I have made while trying to solve this is...
I have the batteries, negative cable, grounded to frame that holds alternator, I have seen were it has been bolted to the motor block,should I move this? Second, I have seen a picture where the body of the alternator has a ground attached to it. (do not have grounding stud on alternator, just a extra mounting hole for bolt). Third, does the voltage regulator need a extra ground or go with star washers.(voltage regulator has an extra contact "bar" that points out the top of regulator. Other side is where brown wire feeds out.) I am not sure what this is for.
thanks for your replies, id be stuck without them.
solon

droldsmorland

Battery ground/negative should be on the block/head. It requires a shallow bolt/lock washer assembly. Make sure its clean and tight and doesn't bottom out before tightening up.. IMO you cant have enough grounds. The engine block as well as the car body needs a good clean path back to the battery via its grounds. There should be a braided cable from the rear of the driver side head to the firewall. The VR body needs to have clean contact to the fire wall how ever you want to accomplish this. Factory used a star washer. Anytime I clean a ground I like to seal it with battery terminal protector or clear ignition spray. The tab at the top of the VR is for a radio noise condenser/suppressor. It should be there.
The alternator should have 3 connections, the main battery lead and the two smaller wires 1&2 plugged into the side. Its not a bad idea to insure the alternator body is getting a good ground through the brackets and attaching bolts. No need for a separate ground but its not gonna hurt anything either.

droldsmorland

Here is an example of the ground strap. Its the flat rusted thing that bolts to the firewall under the letter N on the firewall crayon marks. This example is a small block Chevy. It doesn't really matter how or exactly where you run this strap just needs to be there. Generally its bolted to one of the heads then to the firewall. If your interested in originality you need to get the fisher and Olds assembly manuals.

srholt45@gmail.com

I will definitly give those suggestions a try. I was looking at the picture you posted that has the alternator. I see that the pigtail posts are aligned like this "--". I believe that is an internal regulator. The one on my car has the external "II" style.
I also wound up with an extra alternator, and pigtail, that has the "--"studs. My question is ,if I do need to try and switch alternator, where does the pigtail hook to if you remove the external regulator from firewall.
thank you.....solon

droldsmorland

Correct. The pic is for general ref sorry, I removed it. See attached for clearer view... You have the externally regulated system on your car if you have the firewall mounted regulator (as OEM). You need to use the associated externally regulated alternator. There are pros and cons to leaving it alone or to convert to an internally regulated alternator. Personally with a solid state VR Id leave the system alone. For a street rod Id be inclined to convert. Cleaner look.
Too much detail for me to spoon feed here. Get on the Googler and do some searching. This subject has been discussed here and on the net on how to trouble shoot both systems as well as how to's on the conversion. Below links are an examples.


http://www.wallaceracing.com/alt-conversion.html

droldsmorland

Heres part 2. Its Chevelle but is the same basics for Olds Watch the vid after this one too. There a ton of these on YouTube. These are just some quickies I pulled off for you to view. If you search further you should find an Olds.