1982 720 KC 4x4 alternator upgrade

[720trail4x4]

Adding a winch to my 720 and am already planning to upgrade the battery but would like to upgrade the low output alternator to a more stout amperage to replenish the battery after a winch session. I don't plan on winching a bunch of really heavy, just myself as it's just a 5k lb winch. My idle already dips with just the headlights and turn signals on so a winch will kill it. 

 

Max amperage load for the winch is listed at 300A. Expanding the battery tray and gonna put a deep cycle/rv battery in it. 

[datzenmike]

The 720 alternator is 50 amp. Canadian are 60 amps.

 

I have modified a 2001 Altima alternator to fit my 710's L20B (Z22 isn't any different) The Altima alternator is 100amp. It has a serpentine belt but my '76 Vee pulley fit. The mount on the block had to be modified. Works very well. Wiper is faster, fan blows like a tornado and the headlights don't dim with the turn signals at a stop. The positive cable that I took with it was thicker than my positive battery cable.

[bottomwatcher]

Just a quick look this guy used diodes to boost his alternator output. The method I am used to uses resistors in the sensing wire and a switch. A cheap mod when you need full power out of your alternator and don't wait for the regulater to catch up.

https://expeditionportal.com/forum/threads/alternator-voltage-boost-modification.193869/

[bottomwatcher]

One more explanation 

http://www.smartgauge.co.uk/alt_mod.html

[datzenmike]

Take note: "The total load, and max output amps will not be affected."

 

This is for the rare times when the alternator is not at full charge rate and tricks it into full normal output. It does not make a 50 amp alternator produce 60 amps.

[thisismatt]

There's a reason V belts were phased out on newer cars - they can't handle the load of newer, higher output devices, so keep that in mind when deciding how big to go. Mechman (one manufacturer of high output alts) states the following:

 

Single V belt and 4 rib serpentine belts will start to slip at about 150 amps worth of load. For minimal belt slip, 240 – 370 amp alternators should not be driven by anything narrower than a 6 rib serpentine or dual-V belt drive setup.

[datzenmike]

Totally agree. My sedan had a 80/90 amp KA alternator and if the battery was low it would let out a screech. I would turn the headlights off briefly till it got a grip. No tightening could fix it but it didn't happen often. My 100 amp alternator in my 710 is problem free with V pulley. 

 

100 amps is 12,000 watts. This is just over 16 HP strain on the belt.

[bottomwatcher]

1 hour ago, datzenmike said:

Take note: "The total load, and max output amps will not be affected."

 

This is for the rare times when the alternator is not at full charge rate and tricks it into full normal output. It does not make a 50 amp alternator produce 60 amps.

 

29 minutes ago, thisismatt said:

There's a reason V belts were phased out on newer cars - they can't handle the load of newer, higher output devices, so keep that in mind when deciding how big to go. Mechman (one manufacturer of high output alts) states the following:

 

 

 

I put a 100 amp alternator on a diesel motor on my sailboat with a v belt. It would slip but I couldn't change to a larger pulley because the tachometer signal came from the alternator. Switching a gates green load rated belt solved the problem. I try to use load rated v belts instead of automotive belts whenever I can. A lot more expensive but they don't fail. Matt most of the higher rated marine alternators. Usually 140 amp and above use a dual pulley belt system.

[bottomwatcher]

Dual pully.

https://www.boundlessoutfitters.com/product/balmar-6-series-marine-alternator-12-v-120-amp-j-180-mount-dual-v-pulley/

I run one of these as my voltage regulator.

https://baymarinesupply.com/sterling-proreg-dw-advanced-alternator-regulator.html

Way overkill for a Datsun but really maximizes an alternators potential.

Back to Datsuns. It would be interesting to have a load chart for our vehicles. I think since I have converted almost all my lighting to LEDs my load chart would actually be lower than stock.

[Thomas Perkins]

I use a 60 amp alternator.A 50 amp is too weak.You will have problems with your electrical system not fully working.I had a 50 amp in mine by mistake and it didn't last but a few months and had all kinds of electrical problems.I would fill my gas tank up and it wouldn't read full.

[datzenmike]

The gas and temperature gauges are powered by a voltage regulated to about 8 volts so that when not running at battery (12.6v) or at full charging (14.3v) the readings don't vary. I have noticed with Datsuns that when the tank is low and you first start up the tank reading is whatever but after running for a while when you look, it suddenly has dropped a needle width as the gauge warms up??? Perhaps when low the gas is sloshing around more?

[bottomwatcher]

11 hours ago, Thomas Perkins said:

I use a 60 amp alternator.A 50 amp is too weak.You will have problems with your electrical system not fully working.I had a 50 amp in mine by mistake and it didn't last but a few months and had all kinds of electrical problems.I would fill my gas tank up and it wouldn't read full.

You are using autozone alternaters?

[Thomas Perkins]

Yes.When ever you take one back to get another,make sure they get you the right one.I took one back,it was a 60 amp one,and they gave me a 50 amp one,the fitting was different but i just thought it was a new style type but,it was a 50 amp one.I took it back after it failed in only 3 months and realized it was the wrong one.Then the person ordered me another one and they were doing the same thing.I made sure this time that I got the 60 amp one,it is bigger in size and has a different electrical connector.Never trust any salesman to order the right one,always look at there computer screen when they are ordering you a new one,never trust them.That is at all Auto parts places.Even the Nissan Dealer ships.Don't use Auto Zone's cheap belts.Get Gates.This is the 60 amp one.I've had my 720 for 28 years and only bought one alternator.Never been stranded because it quit working.

Edited January 4, 2023 by Thomas Perkins

[720mintal]

On 1/1/2023 at 4:22 PM, datzenmike said:

The 720 alternator is 50 amp. Canadian are 60 amps.

 

I have modified a 2001 Altima alternator to fit my 710's L20B (Z22 isn't any different) The Altima alternator is 100amp. It has a serpentine belt but my '76 Vee pulley fit. The mount on the block had to be modified. Works very well. Wiper is faster, fan blows like a tornado and the headlights don't dim with the turn signals at a stop. The positive cable that I took with it was thicker than my positive battery cable.

Resureccting this dead thread. How did you modify the mount ? Welder required ? After market brackets ?

[Thomas Perkins]

Mine is working so good with a 60 amp alternator.My Kenwood is wide open.50 amps are too weak.50 amps doesn't have enough ass.I am running with the pack since 1994.Best running 720 in the world...

 

Edited March 18, 2023 by Thomas Perkins

[Thomas Perkins]

29 years of Auto zone parts.Can you beat it..I didn't think so...You got to have the know how..Nissan should of had me design their 720's.Would run forever.As they say in poker,read em and weep...Guess what it needs nothing...Also no junk yard parts...Almost everything under the hood has been replaced.

Edited March 18, 2023 by Thomas Perkins

[datzenmike]

On 3/11/2023 at 2:45 PM, 720mintal said:

Resureccting this dead thread. How did you modify the mount ? Welder required ? After market brackets ?

 

 

Has same fit to mount but changing from serpentine to V belt alters the alignment of the pulley. Depends on the mount. I only ground the body of the mount so the alternator would clear, it's larger diameter, and about 1/4" off the end so it could move forward that amount. An additional 1/4" of washer on the front to replace what was removed so the V pulley would line up.

 

 

Above... note the thickness of the output cable, it was thicker than my stock 710 positive battery cable!!!!!!!! I took it when I grabbed the alternator, trimmed the length, crimped a huge lug on the end and connected to the positive starter lug. Below...

 

 

 

 

 

I don't think the Altima one had the fan on the front but I put the stock fan and V pulley on anyway and maybe a washer spacer so the fan wouldn't rub.

 

 

Made a jumper so the new plugs into the old harness. Uses a totally different plug and I went to a lot of trouble to get the polarity correct. And then got it wrong anyway. Drove it for three years wired wrong. Only by accident I found out and corrected it, no harm done.

 

100amp is twice the stock amount.

[frankendat]

2 hours ago, Thomas Perkins said:

29 years of Auto zone parts.Can you beat it..I didn't think so...You got to have the know how..Nissan should of had me design their 720's.Would run forever.As they say in poker,read em and weep...Guess what it needs nothing...Also no junk yard parts...Almost everything under the hood has been replaced.

That truck is so sexy it's almost porn

[bottomwatcher]

29 years of Auto zone parts

 

Almost everything under the hood has been replaced.

Yep!

 

[datzenmike]

How long did the Nissan parts last vs. how many times have the Auto Zone parts been replaced (under warranty)?

[bottomwatcher]

According to Tommy

Yes.When ever you take one back to get another,make sure they get you the right one.I took one back,it was a 60 amp one,and they gave me a 50 amp one,the fitting was different but i just thought it was a new style type but,it was a 50 amp one.I took it back after it failed in only 3 months.

 

Edited March 18, 2023 by bottomwatcher
Misspelling

[720_Jeff]

For parts that are available for the 720 via Nissan, I strongly prefer those.  Unfortunately, there isn't all that much left that they sell.  Water Pumps just ran out, say within the last year or so.

I know I didn't buy before pandemic, seems like 2021ish.

Alternator's are gone it looks like, starters might be available, same with fuel pump.

 

Of course, what ever Nissan parts that are still available, are several times more expensive.  More expensive or stuck on side of road?  More expensive or spend part of the day running back and forth from parts store to replace something that should almost never break, but did in 9 months, BUT, I got a deal on it!

 

Most of the time, I'll spend.  We only get so much time here, so might as well spend it doing what we like, avoiding chores as we can.

 

 

[datzenmike]

All Canadian 720s got gear reduction starters and the (down there) optional 60 amp alternators.

 

L series starters will also work but they are tilted away from the engine more. Plenty of room. A 280zx or 810/Maxima starter will work. Had an '84 Maxima gear reduction starter on my 620's Z24, it's now on my 710

[Thomas Perkins]

Yeah,most of all real new Nissan parts can't be found.But it's a gamble on replacing our parts with after market one's.We all know that 720's were not put together to last.Another part that is no longer out their is the fuel pump,But I have a brand new one in the box.What happens when ya'll need a heater core,or a radiator.And a A.C. compressor.Or tweeking that piece of shit heating and air that is junk.What about your oem junkie carb.All oem parts are not better.A Weber tops the junkie Nissan carb.Where are you going to get new light fixtures.Even the driver side door switch is not the same as what came on your 720.What about you wanting to replace your oem exhaust.What about hood insulation.And the speedo that quits working.The temperature gauge burns up.No oem alternators,no starters.But as it is.I did a fantastic job in restoring my 720 and no one on this site seems to know how to get it right.They are stuck in the old school days chasing there tails.I noticed a lot of people don't like me cause my 720 out shine's their's.Everyone has a choice of types of oil,transmission fluid that they use.Also hoses,belts and so what.If you were to get in my 720 and drive it.You would beg me to sell it to you.I have converted my 720 better that it came from the dealer.I believe in doing it right for me and i can care less what everyone on this site thinks on what they choose to replace there parts with cause it's their's.So many haters on here that can't be happy.I have gave it about a complete make over..My new Kenwood is not in the truck yet on the video.Hate on this ya'll.Also when you low rate someone who mis spells look in the mirror,you will see a idiot.

 

Edited March 19, 2023 by Thomas Perkins

[Thomas Perkins]

17 hours ago, datzenmike said:

How long did the Nissan parts last vs. how many times have the Auto Zone parts been replaced (under warranty)?

Where are you going to get a brand new Nissan Alternator.I have never in 29 years ever been stranded cause of Autozone parts.Just that junkie Nissan carburetor,Nissan dealer repair people told me it is a piece of shit.