New Truck - '71 521

[mainer311]

The stock 30A alternator is terrible. The lights will dim with the windshield wipers running. Get a 50A alternator from a 510 with A/C. I kept the external VR on mine, and it's been fine.  I even run a powered subwoofer and crap, and it's way better.

[datzenmike]

 After '71 the 521 alternator is 35 amp. The '77 620 alternator is 38 amp and also externally regulated. The '78 and up are 38 and internally regulated.

 

The 521 and 620 don't have much room for the alternator and they are small. I fit a larger diameter later 50 amp alternator but very tight to the lower rad hose and when setting the belt tension it hits the idler arm grease fitting below it. You might have better luck.

[andyZ00m]

Just pulled the battery and have it on the charger to get it back to the driveway...

 

Looking for the alternator part found this but weary of "re-manufactured". Might be fine. This is also externally regulated so would need to replace the regulator as well.

[thisismatt]

I would go with a newer internally regulated alt and be done with it. The original regulators are electro-mechanical, and the aftermarket solid state external regulators are questionable at best. I'd rather have an OEM Nissan alt personally 

[datzenmike]

I don't know what the think about this alternator. Says 521 but under compatibility only shows cars. Also internally regulated alternators were only '78 and up so late B-210, S10, 280z/zx, 620 truck, A10, 720, 810/Maxima, F10. Only cars have enough clearance for them.

 

Also they are $3-400 new so what do you get for $60.

[Crashtd420]

4 hours ago, andyZ00m said:

Just pulled the battery and have it on the charger to get it back to the driveway...

 

Looking for the alternator part found this but weary of "re-manufactured". Might be fine. This is also externally regulated so would need to replace the regulator as well.

If you replace the alternator get it locally for the warranty.... some have good luck others do not....

[andyZ00m]

Gunna go talk to my boy at the auto parts store. See what they can get from Nissan. If I get a modern one with integrated regulator, I'm assuming they would have an alternate wiring diagram for the new scheme.

[datzenmike]

Simple...

 

 

Remove external regulator and cut the plug off leaving wires as long as possible.

Join and solder the solid White and Yellow wires.

Join and solder the White/Red and the White/Black wires.

Plug into the wire harness.... done.

 

The '71 uses a manual choke so no auto choke relay to worry about.

Be sure to solder the connections and use heat shrink tubing if possible.

 

 

[bananahamuck]

1 hour ago, andyZ00m said:

Gunna go talk to my boy at the auto parts store. See what they can get from Nissan. If I get a modern one with integrated regulator, I'm assuming they would have an alternate wiring diagram for the new scheme.

 

1993 Nissan pathfinder is almost an exact retrofit  ,,  has to have V6 engine .. check it out 

   i even have a box of them from PnP 1/2 off weekends just in case

 

You can do the rockauto comparison to see which other years fit. 

.

 

 

.

Edited November 9, 2023 by bananahamuck

[andyZ00m]

So I charged my battery and drove the truck back to the house. Did the tests from the service manual and everything is checking out correctly.

 

What I did notice is the belt to the fan/alternator was SUPER loose (like 2" play). According to the book its supposed to be .3-.5" depression @ 22lbs. My 22lb finger says its correct now. Maybe that's what happened last night, loose butthole belt meant my battery wasn't being charged and finally drained it down.

 

Tested for proper impedance on the alternator which is at 3.6Ohm, which is close to the 5 Ohm its supposed to be, and then tested the voltage output when running at 1100 RPM (aprox) and with the light on (says the book) and its showing the proper voltage of 12.something VDC.

 

 

So while I still think getting modern alternator with regulation is the move, it might not be an immediate problem.

 

I think brakes, dizzy and indicators are first here.

 

Do I have a single or dual?

 

[banzai510(hainz)]

whats the reading with lights off?

I think at 1100rpm with lights on would be a little better voltage maybe like 13.4 or so.

 

belt tightenes? is like 9mm deflection.  I went to a turn buckle set up for the alternator. But you have to pull the rad out to clear one of the water pump bolts. Just do that when you put a alum rad in.

 

3 hours ago, andyZ00m said:

Do I have a single or dual?

 

Thats obvious you have dual points. the main set is the one near the valve cover with the bigger condensor.  if running right now dont fuck with it. the 2nd set of points is more for emssions.  soem people even disconnect the wire from the 2nd set and time the motor only using the first set. Might even run better going up hills and such .

 

 

you must be Rich!!!!!!!!!!!

I dont see alot of Fluke Meters on Ratsun. You High roller.

Edited November 10, 2023 by banzai510(hainz)

[datzenmike]

A good fully charged battery is about 12.6 v not running. A charging alternator should be over 14v.

 

Next time running pull one of the battery cables off. (for no more than a couple of seconds) If engine quits it's not charging.

 

[banzai510(hainz)]

5 minutes ago, datzenmike said:

Next time running pull one of the battery cables off. (for no more than a couple of seconds) If engine quits it's not charging.

 

Mike I used to do that.

It would work with no lights ON.

with lights ON they always died.

[andyZ00m]

35 minutes ago, banzai510(hainz) said:

whats the reading with lights off?

I think at 1100rpm with lights on would be a little better voltage maybe like 13.4 or so.

 

belt tightenes? is like 9mm deflection.  I went to a turn buckle set up for the alternator. But you have to pull the rad out to clear one of the water pump bolts. Just do that when you put a alum rad in.

 

Thats obvious you have dual points. the main set is the one near the valve cover with the bigger condensor.  if running right now dont fuck with it. the 2nd set of points is more for emssions.  soem people even disconnect the wire from the 2nd set and time the motor only using the first set. Might even run better going up hills and such .

 

 

you much be Rich!!!!!!!!!!!

I dont see alot of Fluke Meters on Ratsun. You High roller.

 

35 minutes ago, banzai510(hainz) said:

whats the reading with lights off?

I think at 1100rpm with lights on would be a little better voltage maybe like 13.4 or so.

 

belt tightenes? is like 9mm deflection.  I went to a turn buckle set up for the alternator. But you have to pull the rad out to clear one of the water pump bolts. Just do that when you put a alum rad in.

 

Thats obvious you have dual points. the main set is the one near the valve cover with the bigger condensor.  if running right now dont fuck with it. the 2nd set of points is more for emssions.  soem people even disconnect the wire from the 2nd set and time the motor only using the first set. Might even run better going up hills and such .

 

 

you much be Rich!!!!!!!!!!!

I dont see alot of Fluke Meters on Ratsun. You High roller.

bought this meter YEARS ago at a flea market for 20$. Guy said it was broken but just had corroded batteries. Ez. true RMS and everything.

 

Parts store has a new hitachi 35A unregulated for 200$ (yikes). And they have the remanufactured for 65$. 

 

prolly would need to look at PnP or other for the Nissan pathfinder drop in (or other). 
 

Dizzy is working fine so might not do anything about it now. 

[thisismatt]

4 minutes ago, andyZ00m said:

 

bought this meter YEARS ago at a flea market for 20$. Guy said it was broken but just had corroded batteries. Ez. true RMS and everything.

 

Parts store has a new hitachi 35A unregulated for 200$ (yikes). And they have the remanufactured for 65$. 

 

prolly would need to look at PnP or other for the Nissan pathfinder drop in (or other). 
 

Dizzy is working fine so might not do anything about it now. 

You can get one from a salvage yard on eBay if it's not convenient to go to a local yard.

 

Alt must be putting out around 13.5v or more to charge a battery. Anything less only maintains current battery level which gets lower every start.

[andyZ00m]

3 minutes ago, thisismatt said:

You can get one from a salvage yard on eBay if it's not convenient to go to a local yard.

 

Alt must be putting out around 13.5v or more to charge a battery. Anything less only maintains current battery level which gets lower every start.

That’s probably what’s happening then. Guy I bought it from didn’t have this problem though. With the belt so loose butthole and the low output, either he lied or never drove it. Or both. 

[mainer311]

Next time I have to re-do my alternator, I’m going with a mini Denso. Remanufactured alternators are complete junk, no matter which way you slice it.

Edited November 10, 2023 by mainer311

[andyZ00m]

1 minute ago, mainer311 said:

Next time I have to re-do my alternator, I’m going with a mini Denso. Remanufactured alternators are complete junk, no matter which way you slice it.

What’s a mini Denso?

[andyZ00m]

58 minutes ago, thisismatt said:

You can get one from a salvage yard on eBay if it's not convenient to go to a local yard.

 

Alt must be putting out around 13.5v or more to charge a battery. Anything less only maintains current battery level which gets lower every start.

This is what’s happening. Fully charged battery was 12.6V and after driving around a bit and a couple starts it’s 12.1. 

 

[Finnsfabrications]

I had the same issue, amazing how long these little trucks will run with no charging (in the daylight...😉)

 

I popped my alternator out, tore it apart and saw some issues with brushes and commutator.

I brought it to a local guy* down here in Ventura county, he went over it and added a neat little solid state regulator that fastens right to the body of the alternator. 

Absolutely zero issues to worry about with fitting a unknown alternator and 14-plus Volts charging now... 100 bucks, it was worth every penny.

 

My 521 is bone stock and pretty cherry for a 50-year-old truck. When i first got it, I replaced all brakes and cylinders, rubber lines and most of the brake hard lines. 

Lighting is still a little wonky, but cleaning the fuse block and ring terminals made a huge difference.

 

I still need to sort out the lights and fuel gauge and Big-time paint issues on my little rat but not going to hijack this thread..

 

Good Luck, have fun with it. I drive mine as much as possible.

 

F. F.

 

*If you can find that local guy up there, I would say that's your best bet - ask the hot-rod guys or truck and heavy equipment repair shops are also pretty good at knowing where to find "that guy"

-His shop will be FILLED with all manner of starters and alternators, cluttered but not dirty...

A paper tag with your  name and phone number, maybe a chit with his phone number is all you get.. or maybe not.

has a computer, but probably unplugged... most likely a Rolodex on the counter and at least one illustrated calendar or poster from 30 years ago with an automotive / Bikini theme hanging among the ephemera.... that's your guy!

 

[banzai510(hainz)]

I have a version of this.  I drive around with certqin conditions and just remember what the load level is.

If driving normal speed and its above 13.2 and better with stuff off I say your alternator is fine. esp if a 30/35 amper.

https://www.amazon.com/Battery-Charging-Condition-Alternator-Display/dp/B07422ZPT4/ref=sr_1_2?crid=2RR4OV7W1PVYR&keywords=12volt+cig+lighter+alternator%2Fbattery+tester&qid=1699584237&sprefix=12volt+cig+lighter+alternator%2Fbattery+tester%2Caps%2C132&sr=8-2

 

maybe you have a old battery?

 

As Mainer and I said to you in PM alot of remanufactured stuff nowa days is junk.

soetimes you can find NOS stuff on ebay that say made in Japan. I cant verify for sure.

 

I recently had a WAI branded NEW alternator(China) I got 3 years of out it as a daily driver on my 521. Is that good as a Hitachi from 1969 back in the day. I dont know. Now I dont drive them much since I found soem Toyota pick ups for cheap as daily drivers now. But these Denso alternator last forever that was from the factory.

 

Edited November 10, 2023 by banzai510(hainz)

[andyZ00m]

The Denso site is garbage on mobile. Will check it out on desktop. Seems to only be searchable by model. 
 

totally possible I have an old battery, I mean, it’s an old battery. But seems like also an old alternator. 
 

I do have a couple local wizards who can take a look at it for me. 

[banzai510(hainz)]

No wizardtry. get cig light volt meter and monitor.

 

44 seems cheap and 6 months war not great

 

https://www.ebay.com/itm/284342025221?fits=Model%3A510|Make%3ADatsun&epid=76591450&hash=item42341afc05:g:l9IAAOSwzUxg0UH4&amdata=enc%3AAQAIAAAA8EbZx%2Bu3TpeabNmGiZcz0j26tOa0ZLi%2BXsuVykr9Cb970TKJyhriuUfznjQEVkX6ptmQ8pkJ5zp1tUs4scQgZpthbIk%2FJzl331pbRj4r6RKzRAu%2ByNSSbgXtnLggyoceVvGOO76Ikd%2FgP%2B8wNvUApjdusgNbXQ%2FInKW0s1spuTLdxUdHPJDzmwDHbtRdmWCG7ldDrOeoITVTQP1rPWcHPDcEyYvdQ0wRT6TkJG7jwU8L9FKAb9Ij6yequjyWBCBpj8ATOqxn97F7SH6ofgiRycWoTbRXMpX44%2BDMCX433n2HCmrX2pjWDyAccouviACj1w%3D%3D|tkp%3ABk9SR46Htfb2Yg

Edited November 10, 2023 by banzai510(hainz)

[banzai510(hainz)]

soemone said these guys were better  these are stock 510/521  Wilson rebuilds

https://www.ebay.com/itm/404607528588?fits=Model%3A510|Make%3ADatsun&hash=item5e347cee8c:g:T94AAOSwrxVcsey~&amdata=enc%3AAQAIAAAA8HCWVAqUxfAbWgp8OFXYh8Uy3wt8v56X2Ke%2FtROFnQYtQbg1lq2lF6fRHceJVJ97SNKjuBmTYWRAEMbsIXWuApxrmRcAdVO82izTjX6apJ1NeRiI0JpBwTpOHLaVpgXqGFxD219iOi2A1XIgXJIZqXFKe5xh4fl1xPfeLSdHLuanXX5WC9TiAyl0P6TrNQHKPqnSaUEEi58Coa7AkHbdS%2FvMO%2FowUYSIQlLF7q8RcZuzz5957LKhM428Z%2F%2FgGfNqejHmZJGBF%2BMBNn0HTomkGpetUtox7XfirGlHW%2FdSQHAsrVtU1E17%2BkN4xxB%2FrWvLaw%3D%3D|tkp%3ABk9SR5KHtfb2Yg

Edited November 10, 2023 by banzai510(hainz)

[mainer311]

12 hours ago, andyZ00m said:

What’s a mini Denso?

 

"Mini Denso" is the style of alternator, made by Denso, which is an OEM brand that Toyota (and others) use. Most of their alts use serpentine pulleys, but you can either convert them to V-belt, or find one that comes with V-belt.

Edited November 10, 2023 by mainer311