Alternator or battery?

[siteunseen]

240 shows 13.40 at idle on the positive and negative post. 14.45 volts at 2,000 rpm. Belt is snug, battery and alternator are both old. Any advice would be appreciated.

Amp gauge sits dead in the middle, never forward just backwards when brake lights or turn signals are on.

Thanks in advance. Cliff

[SteveJ]

Um...don't mess with it.

I don't see anything wrong with those numbers or with the ammeter action.

[zKars]

The alternator isn’t charging strongly at idle, but seems to be fine above idle, and that’s not reason to do anything. Yet. Keep an eye on it. If you ever get into a “needle on the negative side” while driving around, then think about doing something.

[Mark Maras]

Does it have an external voltage regulator? I don't remember when they went to internal.

[SteveJ]

Just now, Mark Maras said:

Does it have an external voltage regulator? I don't remember when they went to internal.

Unless modified by an owner, 70-77 have an external regulator. 

[siteunseen]

Thank you both!

1 minute ago, Mark Maras said:

Does it have an external voltage regulator? I don't remember when they went to internal.

I thinks it's external??? Early '72 OE Hitachi

[Mark Maras]

I believe they're adjustable.

[siteunseen]

Seems like I put an internal like a dip stick that I am and it popped all my fuses.

Lessons learned aplenty on here from you guys. Many thanks!

[siteunseen]

Just now, Mark Maras said:

I believe they're adjustable.

Changing the F wire I think? Something like that..

 

[Zed Head]

1 hour ago, zKars said:

The alternator isn’t charging strongly at idle, 

 If you ever get into a “needle on the negative side” while driving around, then think about doing something.

13.4 looks good and 14.4 looks great, right?  

 

[siteunseen]

I dove it for about an hour today. 62 degrees and sunny down here. 

Had some strain on start up when I put fuel in. I'm going to swap the battery out of my 280 over in the next day or two. It's newish, not quite a year old. I have a reman alternator that tested good when I bought it. Thats option #2, the more time consuming. 

No matter the charging problem the car ran top notch after sitting for a few months. A lot more going on in MY head the past couple of months, cars on the back burner until very recently. 

[Mark Maras]

1 hour ago, siteunseen said:

Changing the F wire I think? Something like that..

 

 There is a pair of adjustable points inside the cover. Back in the mid seventies I began to be concerned with a dip in the voltmeter at idle. Armed with no volt meter, little knowledge, and a repair manual, I pulled the cover off and adjusted one set of points. Don't remember which set and I don't remember if I opened it or closed it but it worked. Try Googling "Datsun voltage regulator adjustment".