Alternator/Charging Issues

[906-Runner]

I bough my 1984 Nissan/Datsun 720 about a two months ago, the alternator wasnt charging the battery so I got it tested. Turns out it was bad so I replaced it with a remanufactured one fron my local parts store. Fast forward a month and a half of everything going fine until today. As I'm driving along, the truck up and dies so I coasted to the side of the road and turned the key off. Tried to start the truck but nothing happened, no crank at all. Head lights, tail lights, radio, and door chime all still work. Got a buddy to jump the truck and it ran good but as soon as the jumper cables got disconnected the battery light comes on and the truck slowly starts to die. Was able to drive it to a place to park overnight after jumping it four times over the stretch of 5 miles. Any ideas out there as to what it might be? im thinking its probably the alternator, but seems like if it was a bad one it wouldve been giving me problems all along?

[906-Runner]

I've also been trying to read up on potential alternator upgrades as well as rebuilding the OEM unit. What have people done as far as upgrades? If the stock unit is really only way to go does someone have a used one they want to get rid of? 

[datzenmike]

Next time leave the cables on for 10 min with the other vehicle running. This  will charge up your battery and allow you to drive home in one shot.

 

KA24E powered D-21 Hardbody alternators have a V belt pulley. (newer cars don't) The plastic plug is different so get that with the alternator when in the wrecking yard. Find an original Nissan alternator and not a rebuilt one as they are crap.

 

 

 

 

[906-Runner]

So the alternator from a D21 will be a direct bolt on swap? Might it be possible to rebuild the aftermarket one I have or would that be useless?

[datzenmike]

You can rebuild the one you have but it isn't cheap. That's the trouble with $60 re-manufactured alternators. They use cheap inferior parts. A used original one is better than a remanufactured one.

[MaddieCycle]

I recently had a major journey with my alternator and charging system and wound up getting a crappy NAPA one then had my original one rebuilt by a local reputable shop but it cost $260. Also put in a hot start bypass, put in a new 4 gauge cable direct from the alternator to the battery with an inline fuse, and cleaned out all of the contacts on the fusible links as well as filth in the combination switch on the steering column.  Truck now pulls 14v with super bright headlights.  Posted about it here: