Alternate Alternator Upgrade - Nissan/Infiniti

[Ed Lijewski]

This is the tool I used on the '89 from below.

Made the job easy.

And doesn't damage the sensor wires.

Screenshot_20210820-075516_Chrome.jpg (359.67 KiB) Viewed 3868 times

YMMV

[DPDISXR4Ti]

So I'm back to thinking the '86 - '92 2.9 Ranger/Bronco II pulley is the better answer. As I mentioned previously, it only needs the OD of the spindle pilot turned down a little.

2.5 years later, I guess I thought today was a good day to get this project back on track. I was a little optimistic with my statement above ^^^ in thinking I only needed to turn down the OD of the spindle pilot to get this pulley to work. In fact, it needed 4 separate machining operations to get it totally right to use as you see below. As Dean had suggested, you want the pulley as close as possible to the alternator case. I think I've succeeded in that regard.

Side note... This pulley is used on a bunch of other Fords of the 70's and 80's. I grabbed another one off a Mustang II I stumbled across in the "old car" section at the junkyard.

So far, the only modification required to the alternator was cutting down the casting maybe 1/8" where it surrounds the shaft. The pulley was otherwise bottoming out on the casting before the bearing. You should be able to see the cut down ring in the pic with the pulley not yet installed. I went low-tech for this operation and just did it with a hack saw, cleaning it up with a file and then thoroughly vacuuming up the AL dust. It was just a clearance thing, so no precision required.

NissanAlt-1.JPG (1.01 MiB) Viewed 3512 times

NissanAlt-2.JPG (1.05 MiB) Viewed 3512 times

[zxr250cc]

Hi all,

I have been following this and wonder if you have contacted an alternator rebuilder for help? I think you are in areas where such folks are around, large metropolitan areas, and they could offer help with this.

I looked around on line and found a link to a very high output offering of 220 amp units:

https://www.powerbastards.com/default.asp

Not cheap but great if accurate and reliable. We have Pinto design motors in XR but the alternator listing is the same for Scorpio on some sites. Perhaps a contact with them will offer help?

Cheers

[DPDISXR4Ti]

I have been following this and wonder if you have contacted an alternator rebuilder for help? I think you are in areas where such folks are around, large metropolitan areas, and they could offer help with this.

No help needed here, short of time and motivation. I don't need a big jump in amperage output - another 20A along with better output at low RPM's is all I need.

[DPDISXR4Ti]

For the SENSE wire I have an inline fuse holder that accepts standard bladed fuses. I'll have the fuse up by the battery post.

FWIW - on the Hitachi 130 amp alternator, with the 2 pin connector, the wire closest to the big stud is the LAMP wire. Not sure of the situation with Brad's unit with the curved cooling vents.

Dean, how did you figure out which one was the SENSE circuit and which was the LAMP? Just trial & error on the bench or did you find a schematic somewhere? Once determined, I'm assuming I'll splice the LAMP circuit into the existing circuit 61 (Blue) that goes to the cluster and the SENSE circuit will be new end-to-end and get constant (or ignition switched?) 12V+.

Any chance you have a part# on that Mr. Gasket bracket? Your link to the Advanced Auto site is already dead.

[DPDISXR4Ti]

InfinitiG35AltHrns-2.JPG (1021.48 KiB) Viewed 3476 times

I was looking back through some of the older messages in this thread and noticed I had taken this close-up of the quick-connector, which has a "+" and "-" indicated right on the connector. I can only assume that the + side is for the SENSE circuit and the - side is for the LAMP.

EDIT 7/15/2022 ^^^ This assumption was 100% wrong! ^^^ I really don't know what the + and - indications are indicative of. Just ignore them and use the info provided by Dean and my pic below. I'll leave my original post here if only so someone else doesn't make the same mistake.

[Ed Lijewski]

[quote=DPDISXR4Ti post_id=361052"...along with better output at low RPM's is all I need."
[/quote]

A slightly smaller alternator pulley, ~1/4"‐3/8", would address all but excessive amp draw at extended idle, and would be a simple modification to increase low rpm output.

I've searched for a substitute smaller pulley but haven't yet found one with the same V-belt channel dimension.

YMMV

YMMV

[brokencase]

Dean, how did you figure out which one was the SENSE circuit and which was the LAMP? Just trial & error on the bench or did you find a schematic somewhere? Once determined, I'm assuming I'll splice the LAMP circuit into the existing circuit 61 (Blue) that goes to the cluster and the SENSE circuit will be new end-to-end and get constant (or ignition switched?) 12V+.

Any chance you have a part# on that Mr. Gasket bracket? Your link to the Advanced Auto site is already dead.

From my earlier post...

"If you use the aftermarket Hitachi 2 pin connector - the yellow wire on that connector goes to the Scorpio's green LAMP wire. GREEN is sense and goes up to positive on the battery through an inline fuse."

I believe I determined this after doing some searching around on the web.

Look at my installed pictures earlier in this thread to see which side the green and yellow go to for clarity.

I have no idea what part number the bracket is. If I were to do it over again I think I would have gone to the junk yard and try to find one that would fit better.

[DPDISXR4Ti]

"If you use the aftermarket Hitachi 2 pin connector - the yellow wire on that connector goes to the Scorpio's green LAMP wire. GREEN is sense and goes up to positive on the battery through an inline fuse."

Okay, got it. I see now you discussed this on page 6.

So for me, using a junkyard clipped-off factory pigtail, White w/ red stripe is the LAMP circuit and goes to the cluster. Green w/ black stripe is the SENSE circuit and goes to 12V+. That's actually the opposite of what I was guessing, so glad I checked.

I made some good progress today...

Nissan110Alt-2.jpg (257.74 KiB) Viewed 3349 times

The factory thickness of the "spacer" on the bracket was 3.125". I milled it down to 2.810". I also bored the hole out to 10mm so that I could use the Nissan bolt which nicely screws into the captive nut on the Nissan alternator.

Nissan110Alt-3.jpg (361.64 KiB) Viewed 3349 times

Five washers fit perfectly snugly and became my hi-tech customized spacer. Edit 7/23/22... Funny enough, there was a slight difference between the two alternators I've fit so far. The first one required a spacer (the aforementioned 5 washers) of .340" thickness while the second one needed .330". If I get around to actually fabricating a spacer (a good idea, BTW), I'll just go with the .330". I'm sure tightening things up can make up the 10 thou.

Nissan110Alt-4.jpg (337.43 KiB) Viewed 3349 times

Nicely aligned now. I was able to use the original adjustment arm from the Bosch alternator. I used a thick washer under the NON-slotted hole of bracket to get it away from the alternator body. Apparently the case from 130A Titan alternator is a little larger than the 110A I'm using and so you have some greater space conflict issues with that one. I also didn't need to clearance-grind the iron bracket as Dean did with the Titan alternator. I get sufficient rotation of the alternator without conflict so that a belt can be slipped on and tightened.

Nissan110Alt-1.jpg (497.79 KiB) Viewed 3349 times

[brokencase]

You might want to bench test like I did to confirm the alternator works and your connections are kosher before installing in the car.

You'll need a car battery, a drill, an incandescent dash bulb, multimeter, and some clip leads.

[DPDISXR4Ti]

Just to confirm with a pic, here's how the wiring works for the 2-wire Nissan spec Hitachi or Mitsubishi alternators. Note how the wiring approach used here for the SENSE circuit is to just run a short jumper to the main 12V+ line. That's actually the same as how most 3G swaps are done. Dean's suggestion is to run a separate wire back to the battery with an in-line fuse. Either should work. Note that this is a different Nissan spec alternator than the one we're using, so the main power lug is located differently.

NissanAltWiring.jpg (53.36 KiB) Viewed 3322 times

[DPDISXR4Ti]

I found I wasn't quite done with the mounting and needed to fine tune things a bit today with the adjusting arm. Step one was to squash it with a vise to get the little bit of offset out of it. Then I found I needed to space both ends out just a bit so that it wouldn't hit the alternator body - two washers under the top pivot bolt and three under the slotted opening. Original length 890mm (~35") belt works fine.

Now I'm done with the physical mounting and have the electrical hook-up done as well. For now I'm just going to re-use the factory wiring. I'll come back another day and replace end-to-end.

NissanAltBelt.jpg (573.12 KiB) Viewed 3294 times

[brokencase]

Not a fan of the little jumper for sense. I think it is better that there is a dedicated sense line going up to the battery.
I fused it because that is what I saw in a Nissan schematic online. I don't know if I posted that earlier in this thread, but I'll look around for it.

I think they do that separate sense line because of the resistance of the main wire that goes up to the battery and the strong currents that flow through the main wire. The sense line carries no current as it is only measuring voltage AT THE BATTERY.

I guess a better way saying it is that the regulator in the alternator needs to know the voltage at the battery and not the voltage that the alternator is producing locally that then goes through a big wire that goes to the battery. These voltages are not the same.

A good example is if the battery is low and the alternator is putting out max current. So lets say resistance of the big wire is 0.02 ohms and amps is 130. V=IR = 2.6 volt drop across the big wire. See the problem? Its not so much about the low resistance of the big wire, as much as it is about that high current.

The issue is exacerbated if you do not upgrade the main wire from the alternator to the battery (which I also did).
This is because the stock wire is designed for the weak output of the original alternator and consequently has a higher resistance. I just ran a secondary big gauge wire in parallel with the existing big wire.

Upgrading the big wire is often overlooked by owners of British sports cars that upgrade with an alternator swap.
In some cases the cars originally had a generator that put out about 10 amps and the main wire in the original harness to the battery is very small gauge.

[DPDISXR4Ti]

All good points Dean. For now I'll take the easy way out so that I can get this multi-faceted project done and the car going back down the road. If nothing else, it'll be a good base for before and after test data; first just upgrading the alternator, and then coming back and upgrading the wiring.

[DPDISXR4Ti]

Just took the inaugural journey with the Nissan alternator. Indeed it seems to work well - charging voltage was initially right up to 14.0V and then seemed to hang around 13.8 once underway for awhile. It went down to ~13.5 if I had the HVAC fan on high at idle. That was the extent of my load testing.

The only odd thing is that the battery light on the instrument cluster stays dimly lit now. Hmmmm....