76 possible electrical problem

[bhermes]

I am going to be buying parts on Monday and wanted one last clarification. Is there an advantage in gettng the alternator with the internal regulator over just replacing the current external regulator with an better one? One of the earlier posts discussed getting the external regulator from NAPA.

[SteveJ]

The advantage of the internally regulated alternator is that it has a higher output.

[bhermes]

Bare with me. A higher voltage output? I am currently getting voltage readings at the battery of 17-18V.

I believe I need something less than 15.5V.

[sblake01]

He means a higher amperage output but if the regulator is bad, I'd just replace the regulator. To convert to an internally regulated alternator would be just that; a conversion, and would require other work.

Edited February 26, 2012 by sblake01

[bhermes]

Great. I was a mechanical engineer. Always struggle with voltage and current.

For now I will replace the external regulator and see if that fixes the problem.

[SteveJ]

Great. I was a mechanical engineer.

Well then, I think we may have found the source of your problem.

Of course, this is how torque specs for an electrical engineer: Tighten as hard as you can. If the bolt breaks, you overtorqued the fastener.

Now here is a little known fact about electricity. Many people assert that electricity is the flow of electrons. It is not. It is the flow of magic smoke. The smoke travels in the wire. When you let out the magic smoke, there is no more electricity to flow.

[5thhorsemann]

Yes, the internally regulated alt consolodates two potential problems into one package. It also is easier to find one in a pinch if it fails and it has a higher current output. I would strongly recommend the headlight relay upgrade on a 240 or 260 along with this upgrade. I'm not as familiar with the 280Z electrical system, so maby one of our more learnid 280Z members can chime in on this comment.

[Zed Head]

For the record, the 280ZX alternators only put out more current at ~2500 RPM (~1250 engine RPM by pulley ratio if my math is right), according to FSM specs. At full output, they're the same at 60 amps. And the specs are for factory alternators, not aftermarket. My experience with one auto store rebuilt internally regulated alternator is that it was lower output at low RPM than an old Nissan made 1978 factory alternator.

Just something to think about. In theory, if you were working with Nissan made parts, the internally regulated alt would give more output at low RPM. But in reality, your old Nissan alternator, with a new regulator might be a better bet than a "new" rebuilt internally regulated alternator. The auto store alternators are known for poor quality.

[5thhorsemann]

My 73 came stock with a 30 amp alt, the IR 60 made the car much more reliable and drivable after dark. FWIW

[Zed Head]

Looks like you could get 50 or 60 amps in 74. 76 had 60. 60 auto store rebuilt amps would probably be better than 30 Nissan amps, for sure.

If the OP does decide to do the swap, don't forget about the brake warning lamp check relay under the passenger seat. It might get battery power after the swap, instead of the designed "engine running" power, and drain the battery. It's caught a few 1976 owners, including me.

Basically, if you want simple, just replace the regulator. If you want to dig in and modernize your car, be prepared for a little time and aggravation.

[bhermes]

Wow. OK, after some consideration, I have removed the regulator, I beleive came from either Oreilleys or Advanced Auto, and have ordered a new one (external) from NAPA. I will be installing on Friday and hopefully the problem will be fixed. If not I will be asking for a little more help or next step. Pray, cross your fingers, or do the 280z dance(if there is one) and we will see what happens.

Thanks for all of the help and guidance.

[bhermes]

OK. Not the voltage regulator. NAPA part was the same as the one already on the car. NAPA is telling me that the alternator should not be able to put out that much voltage even if the regulator was bad. Not sure whats next. Again already replaced 2 alternators and battery.

I think I am going to take the car to a electrical auto shop.

Any other suggestions?