521 Wont Charge

[Rotarded]

Hello everyone,

 

I have been lurking all over this forum recently after aquiring a 1972 Datsun 521. Its the stock L16 with a 5 speed dog leg swap. So far, I have done a weber carb with electric choke and deleted points, new battery and alternator. I read that the 510 alternator with AC was 60amps so I went and go it, installed it and truck fired up no issues. I went to check my meter and its showing only 12.5v while running. I checked the wire from the BAT terminal to the starter, the ground is on one of the lower alternator mounting ears and the T connector is plugged in.

 

I started reading about the voltage regulator so I went to check it on my truck and the wires were cut from it and it has some wing nuts over a couple of the chassis side connections jumping circuits. So I went to the parts store and got a brand new regulator and plugged it in, fired it up and still no change in voltage but I noticed a burning electrical smell so I unplugged it. 

 

Things I notice: 

-With jumper to VR the IGN light stays on after starting.

-Without jumper plugged in the VR the IGN light stays off after starting. 

 

The previous owner installed a newer ATC blade fuse block, all fuses are good and intact. I have the electrical diagram and the charging circuit for the 510 that's available still online. Its odd because the VR was bypassed as if they were using an internally regulated alternator but I its using an externally regulated? Today I will get an amp clamp on it to see if its putting out voltage. I checked the voltage at idle but I should have 13.5v even at idle with the L16 correct?

 

Any input would be great, thank you. 

[Draker]

The F  or field terminal on the alternator has to have 12v, otherwise it won't 'turn on'

[Draker]

Also, even though it's new, don't be afraid to have it bench tested. Just because it's new, doesn't mean it's good. 😉 

[Crashtd420]

I think you need to know first if you are using and internal or external regulated altenator...

 

Then you need to check the wiring for the voltage regulator to see if it is bypassed correctly or not or not at all

 

What alternator did you buy?

 

[Rotarded]

1 hour ago, Draker said:

Also, even though it's new, don't be afraid to have it bench tested. Just because it's new, doesn't mean it's good. 😉 

100% I have been reading that I will get it tested. I will also check for 12v at the F terminal. This is while running you mean yes?

1 hour ago, Crashtd420 said:

I think you need to know first if you are using and internal or external regulated alternator...

 

Then you need to check the wiring for the voltage regulator to see if it is bypassed correctly or not or not at all

 

What alternator did you buy?

So I am using a 72 Datsun 510 alternator that had AC so 60 amps. It should be externally regulated as that's what it says online for the description. Assuming that is of course.

 

https://www.autozone.com/batteries-starting-and-charging/alternator/p/duralast-alternator-14118/334268_0_0?searchText=alternator

[banzai510(hainz)]

Key is was this working before you swapped parts????????????

Put OLD back in!

 

If you still have a external voltage regulator then you have hopefully a external alternator. Going by the photo from Vatozone it look light thee correct one.

2 hours ago, Rotarded said:

fired it up and still no change in voltage but I noticed a burning electrical smell so I unplugged it. 

I got a Vatozone reg and it lasted about 2days and put a old mechanical one back in and was fine..

 

2 hours ago, Rotarded said:

Things I notice: 

-With jumper to VR the IGN light stays on after starting.

-Without jumper plugged in the VR the IGN light stays off after starting.

this has me worried if stock should be no jumpers.

 

Most time people use the newer IR internal volt get from a later Datsun. But then you have to disconnect the choke relay as it will drain the battery.

Edited December 11, 2024 by banzai510(hainz)

[banzai510(hainz)]

Haver photos of this JUMPER??? take photos

 

 

take VR out and smell it. Then the circut burnt if smalls like smoke

 

recheck your fuses also in case

Edited December 11, 2024 by banzai510(hainz)

[Rotarded]

Just now, banzai510(hainz) said:

Key is was this working before you swapped parts

 

If you still have a external voltage regulator then you have hopefully a external alternator.

I got a Vatozone reg and it lasted about 2days and put a old mechanical one back in and was fine.

 

this has me worried if stock should be no jumpers.

 

Most time people use the newer IR internal volt get from a later Datsun. But then you have to disconnect the choke relay as it will drain the battery.

So the alternator was working before I changed it, its just it was covered in oil and the lights would dim while headlights and all the lights were on. Battery is brand new, starter is new, so I decided to upgrade the alternator before I add stereo and other stuff. I will have a look at the old alternator but it was same in connections, T connection with one BAT wire and one black ground wire that was on the lower mounted ear of the alternator. 

[banzai510(hainz)]

the later IR ones have same connecctions but a give away for the early ones is the black cage.

 

Put the old alter back in and volt reg and see what happens.

I think you introduced a bad part changin all at once is bad with new part suppliers of low quality.

 

E on back of alt is the black ground wire with screw hole

 

 

My 521 has had alot of electrical issues  over the years. Most people would have scapped the truck by now. Long as the harness is not burnt its usually corrotion or bad parts

Edited December 11, 2024 by banzai510(hainz)

[Crashtd420]

1 minute ago, banzai510(hainz) said:

the later IR ones have same connecctions but a give away for the early ones is the black cage.

 

This is key, what type was the old alternator?

[banzai510(hainz)]

As Crashed said what was the old alternator? You still have it or you needed the core?

 

If the old volt reg on the side of the engine bay was not used that means the previous owner had a Newer IR alternator in there.

If the Orginal VR was stll in there hooked up to the 6 pin connector then you order the correct older alternator.

 

take photos

Edited December 11, 2024 by banzai510(hainz)

[banzai510(hainz)]

thi is a diagram of the Later Alternator installs which the orginal VR is removed(BYPASSED)

[Crashtd420]

I actually like this diagram a little better... closer related to the 521 with the choke relay....

 

 

If bypassing as it was said earlier the choke relay is now getting constant power from the yellow wire... 

The relay Either needs to be unplugged if not being used or you can cut the yellow at the relay and connect it to the white/blue at the relay.. that should be ignition power.... 

 

[Rotarded]

I will have to figure out what host I can use since photobucket is no longer around. So if you are facing the back of the connector, left to right.

 

Top row

1 White/Red

2 White

3 Yellow

 

Bottom row

4 White/Blue

5 White/Black

6 Black

 

So the configuration that it had when I bought it is pin 1 White/Red is jumped with pin 5 White/Black and then pin 3 Yellow is jumped with pin 4 White/Blue.

[banzai510(hainz)]

if the engine harness connector has the WR/shorted to the White Black    and the yellow shorted to the white  (This is a 510 schematic think the 521 is the same)  I cant find it right now.

 

This means the alternator in the truck was a Internal VR alternator for a later 620 truck. Then you bought a  50amp External Volt reg alternator for a 72. which is external VR type. and needs a External BOX vort reg on side of the engine bay.Datzenmike would know the years a 620 had the small 35amp Internalvolt reg alt.

 

So I think you miss matched stuff. So this is my best guess as of right now.

 

I use the engine harness colors as I seen people use the VR side of the wires but some are not correct when the aftermarket made the . Drawing below is the engine side harnesscolorscolors.

Edited December 11, 2024 by banzai510(hainz)

[banzai510(hainz)]

If the  wire JUMPERS(shorts) in the connecter where like in the drawing One could just pull them out and put a external volt reg back in to the 6pin connector and the 72 alternator  it should work

[Rotarded]

20 minutes ago, banzai510(hainz) said:

If the  wire JUMPERS(shorts) in the connecter where like in the drawing One could just pull them out and put a external volt reg back in to the 6pin connector and the 72 alternator  it should work

I am almost off work and I will shoot home and get a photo of the alternator that I took off. I think my alternator was indeed bad as anytime I had turns and lights everything would dim. How will I know if the alternator I took off is an internally regulated?

[Rotarded]

2 hours ago, Crashtd420 said:

I actually like this diagram a little better... closer related to the 521 with the choke relay....

 

 

If bypassing as it was said earlier the choke relay is now getting constant power from the yellow wire... 

The relay Either needs to be unplugged if not being used or you can cut the yellow at the relay and connect it to the white/blue at the relay.. that should be ignition power.... 

 

So if I am reading this correctly, it looks like they want Yellow and solid white together, and on my jumper I have yellow with white/blue strip. 

[mklotz70]

If you need a factory manual for reference, you can download them from my site for free.  There's links at the bottom of this page for a couple of other sources that should have them, too. 

 

http://www.bluehandsvideo.com/manuals.html

[Crashtd420]

12 hours ago, Rotarded said:

So if I am reading this correctly, it looks like they want Yellow and solid white together, and on my jumper I have yellow with white/blue strip. 

That would work, it just supplies ignition power instead of constant,  so that actually helps with the choke relay.... once the key is on the alternator doesn't know the difference....

[Crashtd420]

13 hours ago, Rotarded said:

 How will I know if the alternator I took off is an internally regulated?

Internal...

S/L

[Crashtd420]

Externally regulated...

 

[banzai510(hainz)]

got photos of your alternator you had in there? when it was working?  if the wires were already ujumpered sound like it was already a Ilater IR type alternator in there then you bought the old style which you need to convert back to stock.

 

So since were jumping all over the place in figureing this out I give up. This is a simple fix. You smelled smoke so hope the wires in the truck didnt go bad.

But you said you bought a external volt reg and hope that smoked if you really bought one

 

here is a photo of a later external VR shorting method from a 620(uses a round connector)

Edited December 12, 2024 by banzai510(hainz)

[banzai510(hainz)]

20 hours ago, Rotarded said:

got a brand new regulator and plugged it in,

To me you got to pull the shorts out if you bought a regulator. cause the truck was modified to run the IR type alternator.

 

then you bought the stock &2 alt and a stock 72 reg reg so you go to take the JUMPERS out.

 

But Now Im not a mind ready so I dont know exactly were we at since you said you bough a external volt reg and smelled smoke.

 

post photos.

 

How about just put it back the way you had it.

521 with a 30/35 amer are alwasy weak you just got to learn to keep heater off at idle maybe up the idle rpm.  yes the turnsignals are slow with everything on lights ect....  You have to make sure you get the alternator thats a 50 amper for a 521/510 as the later 50amper for a car had the bigger ear bolt holes. the L16 and esp on a 521 had the funky sheet metal atl bracket that I hate.

 

 

hope not to loose another 521 this is a ez fix

Edited December 12, 2024 by banzai510(hainz)

[datzenmike]

17 hours ago, Rotarded said:

So the configuration that it had when I bought it is pin 1 White/Red is jumped with pin 5 White/Black and then pin 3 Yellow is jumped with pin 4 White/Blue.

 

To convert a system to run an internally regulated alternator join solid White to solid Yellow. Join White/Red stripe to White/Black stripe (your  Blue is likely Black)

 

 

The internally regulated is preferable to the external regulator else people wouldn't convert. Simply return the 510 alternator and get one from any Datsun AFTER '77 when they changed all to internally regulated.

 

I found the car alternators were too large a diameter to fit the 521/620 properly. A '78-'79 620 alternator should easily fit but only 35/38 amp.