Voltage Regulator?

[FiremarshalBill49]

Besides the red charge light on my dash, how can I tell if my voltage regulator has gone "Tango Uniform" on me? The red charge light started coming on shortly after I installed a new ignition switch.  Sometimes it goes out but mostly it stays on now.  Engine runs fine, battery is new and the connections are clean and tight, alternator belt is good. 72' Datsun 620 with a stock L-16. Any suggestions?  Looks like a new voltage on eBay is around $36.

[racerx]

voltmeter across battery while car is running.  if voltage is like 15 volts then no good. Should be like 14.3 or something.

[Dolomite]

Start the vehicle, bring it up to around 2k rpm, and have someone hold a voltmeter across the battery terminals. It will read above 14v for a short time, then drop to about 13-14.5v if the regulator is good. If it stays well above 14v, the regulator is foxtrot uniform charlie kilo edward delta.

[flatcat19]

Test alternator before throwing parts at it or condemning regulator.

[datzenmike]

Battery....

 

12.6 fully charged and engine off.

14.3 ISH engine running.

On a 35 amp 620 alt. with heater and headlamps on, low 13s maybe into the 12s at idle.

 

 

Look on the fuse box, left hand side closest to the driver. Should be a 10 amp with two 15 amp fuses behind it. Should go to a Blue/White stripe wire. Change that fuse and see if the problem goes away. This is just a guess, but no harm done. This fuse powers the red charge light.

[DanielC]

If the charge light goes out at higher engine rpm, I would first suspect the brushes in the alternator.

[banzai510(hainz)]

was the switch a exact replacement? otherwise I think the alternator is going out.

Go on the web and buy a cig lighter tyep volt meter. it plugs in to the cig lighter socket.. they work great. tells you way before your light comes on that soemthing is up if you monitor them regularly

[MikeRL411]

If the charge light goes out at higher engine rpm, I would first suspect the brushes in the alternator.

 

It is 26 years  old, and I know that you did not think that 26 was old age personally but that's life.  Brushes for the alternator are readily available and only cost skinned knuckles to remove, replace and reinstall .

[FiremarshalBill49]

UPDATE... I installed a new external voltage regulator (ImportDirect PN 29-0133 that a friend happen to have) and now the dash charging light is still ON at high idle, but it DOES go out when the engine reaches 2000 rpm or higher.  Could the 45-year-old factory alternator just need new brushes?  What is involved with swapping out to a 78'-79' alternator with the internal voltage regulator?

[flatcat19]

Jumping 2 sets of wires together and installing the alt. It's really easy.

[racerx]

Take the alternator to oreillys or AutoZone and get it tested.

[banzai510(hainz)]

So your saying buy putting n a new volt reg your light stays on longers before it shuts off?

How about LOAD test thi . Raise the revs  till the light goes out. then put you heater and lights on and if the light comes back ON you got a weak alternator.

 

Buy a cig lighter volt meter so youll know necxt time if its gpiing to go out before the IGN light comes ON

 

Importdirect is a good brand of jap made parts. where you get this?

 

You have a L16 alt and it uses the smaller bolts thru the ears. A later model truck might use the bigger bolts thru the ears of the alternator. Im not positive on this as I never owned a later model truck. I know the Cars used a 50amp and had the bigger holes.(L18/20)

 

Rockauto has new 35ampers(china) for 65$ for the 510/521 which I think was same as first year 620 with L16.

 

 

jumper wires

its blk wht wire short to the red wht wire

white short to the yellow

 

Just make 2 blade connector wires and insert in the  engine side of the harness. where the volt ref was plugged in.

 

if the 45 yr old alt just need brushes why not get a new one. Tearing it down isn't worth it in my opinion. I did it once and said, Fuck it. faster to put a 6 month rebuild in there

[FiremarshalBill49]

Took the beast into my mechanic today and the 45 year old alternator is toast.  Rebuilt alternator is ordered.  When I'm finished it'll be more new than old!  I keep telling myself, hell, it's only money, huh? To be continued...

[flatcat19]

Now would have been a good time to buy an IR alt. vs going original.

 

280zx had 60amp IR alternators. Plenty of power.

[red13]

Swapping to internal reg would be a good idea,  Dave irwin makes a ZXP plug that works for 72-73 620 that he made for a early s30.  Only thing I learned from Mike was the heater choke relay needs a wire changed as well.  

[datzenmike]

Heater relay MUST be unplugged, and another 12 volt source that is switched by the ignition, used to power the electric choke. Best one I have found is to splice the Blue choke wire to the Red idle cut solenoid. 

[Shwifty]

Is the heater relay the piece before the ex.regulator , I don’t have electric choke or stock carb can I leave it plugged in 

[banzai510(hainz)]

if you had a auto choke Datsun then you have a heater relay on the vehicle

[datzenmike]

7 hours ago, Shwifty said:

Is the heater relay the piece before the ex.regulator , I don’t have electric choke or stock carb can I leave it plugged in 

 

You could, as long as you have the external regulator for the alternator. If later you switch the wiring to run a newer internally regulated alternator you WILL have to disconnect the auto choke heater.

[Minitruck]

I have a 73 620 battery doesn’t hold  charge so I bought a new alternator come to find out I think it’s my regulator but the regulator only has four terminals where can I find one 

[banzai510(hainz)]

rockauto or a local parts store should have Volt Reg.

 

maybe battery is good and the alternator not charging.??? and you running off the battery. or you have a battery drain

 

believe me this works , simple for most dumbasses to figure out. Long as the cig lighter has power.

 

anytime a battery issue alwasy ck the fuses and or replace and look at the meter. this will catch the proplem before the IDIOT Light come on.

 

https://www.walmart.com/ip/Equus-Innova-3721-Battery-and-Charging-System-Monitor/15137663