Big Brother is going 3G

[ArdWrknTrk]

A) if you decide 130A (148 mm diameter) you're going to want the additional adjustment range afforded by the 8.25" pivot length.

Also, I don't know anything about belt slip, except for the first couple of seconds from a tired battery.
Using a double belt means that you have to find a crank pulley with two adjacent sheaves the exact same diameter.

I haven't bothered to look for this unicorn yet, because I don't have any problems

[Gary Lewis]

I think I found such a crankshaft pulley for Dad's truck.  I say "think" because I've not mounted it yet to find out if the sheaves line up with the alternator's pulley - which I had to make.

The issue is that the vast majority of pulley's have different sized grooves for the belt driving the alternator vs the belt driving whatever else was installed.  Apparently there are very few crank pulleys with the same sized grooves.  Ditto the alternator pulley, but since those are made of aluminum and I have a lathe, I modified one.  But that's not possible with the stamped crankshaft pulley.

Personally I wouldn't worry about it, at least not initially.  If you have a good wrap of the belt on the pulley and an LRC regulator I think you'll be fine.

[BigBrother-84]

Quality Power sells Small Case High Output replacement units.

Any advice about the WAI brand?
I think this is what Quality Power sells.

[ArdWrknTrk]

You don't need it.
Stay with a stock 95A 3G.

The GOOD reason that the small body is limited is that the fans and heat sink are smaller and can't shed heat fast enough for more than 130 (maxed out)

[BigBrother-84]

[BigBrother-84]

Just to be sure I understand correctly, since my main concern is the amp at idle, the different stock Ford alternators offer these values:


• Big Bro's 1G = 15 Amp ±
• 3G 95A = 64 Amp ±
• 3G 130A = 80 Amp ±

[Gary Lewis]

Jeff - I'm not sure where those curves come from, but our page at Documentation/Electrical/Alternators shows that DB Electrical's tests found that Jim's 130A 3G put out 106A at ~550 engine RPM, assuming a 3:1 pulley ratio.

And that page also has the chart below from Ford's documentation on a 60A 1G.  It says a 460 would have a 3:1 pulley but doesn't show that curve.  But I'd guess the output would be about 30A at 550 RPM.

Using the 130A 3G ratio of 106A/130A I'd guess a 95A 3G would put out about 77A at 550 RPM.  More than twice that of a 1G.

[ArdWrknTrk]

What are you looking to drive at idle?

If you're concerned about output, find yourself a 200A Mitsubishi or Leece-Neville ambulance alternator.
They were made for that...

[BigBrother-84]

Gary Lewis wrote

Jeff - I'm not sure where those curves come from

This graph is part of a 2019 Motor Trend article.

[BigBrother-84]

ArdWrknTrk wrote

What are you looking to drive at idle?

Jim, I use Big Bro once a month during winter time, just hauling manure trailer on the farm.  And get him back in his garage.
I have a maintenance charger plugged in, but I would feel better to know that while idling there is a sufficient amperage.

That’s why I call it my “main concern”.  This doesn’t mean I would not be happy with more amperage at higher rpm.
😉

[Gary Lewis]

I would trust Ford documentation and that of DB Electrical before trusting something in a magazine.  I can't say Ford and DB Electrical are right, but I'd bet on it.

In any event, regardless of which # you believe, if Big Bro is idling with the lights and heater on you'll be very close to not having enough current from the alternator to keep the voltage up with a 1G.  But you'll have more than enough with either of the stock 3G's.

[ArdWrknTrk]

∆∆∆ What he said, x100!!!

[BigBrother-84]

Gary Lewis wrote

In any event, regardless of which # you believe, if Big Bro is idling with the lights and heater on you'll be very close to not having enough current from the alternator to keep the voltage up with a 1G.

Yep, the fan lowers and the lights dim a little, when idling in cold winter time.

Gentlemen, I need some input to choose a right an reliable model from a renowned manufacturer.
As well as for a V-belt pulley model.
There are so much choices and brands out there!

This 1G is running since 80’s and the last thing I want is to replace it with something that will not last.
As I already said, not looking for a bargain, willing to pay the fair value for a solid product.

BTW, not looking neither for a chrome $ look.


I understand that the 95A (7”) is the recommended one in my case.
Go for it.
But to be frank (just curious), I don’t understand why a 130A could not fit.  There’s plenty space, the top would be bolted a the same place:  Why the lower “arched” bracket could not change angle and accommodate it?  Or maybe a different tensioner could do the job?
In other words, why going from 7” to 8” seems difficult, maybe some other wider dimensions I don’t understand?

[Gary Lewis]

Jim knows more about this than I do, but I'll respond anyway.

Don't worry about the pulley.  Whatever pulley it comes with you'll take off and put your pulley on in its place.  So just concentrate on the alternator.

And the 130A unit will work.  So if that's what you want go for it.

As for a brand, Jim has had good luck with DB Electrical.  John/Machspeed, whom you met, had bad luck with them.  I'd still buy from them, but you could go down to your local parts store and buy one of theirs as that would give you someone to deal with later without shipping if you have problems.  And if you get one with a lifetime warranty you should be golden.

That's one of the beauties of going with a stock 3G instead of some fancy one-wire alternator.  They are available everywhere and if one fails while on the road about any parts store can get you a replacement quickly.

[ArdWrknTrk]

The bigger body of the 130A limits your adjustability if you use the short 7" pivot.

You can try it.
It MIGHT work on a Windsor.
I can assure you that you don't want to use a 7" 130A on a 385 V-belt engine.

There never was a 3G with a V-belt, but ALL alternator shafts are 17mm, so the pulley swaps across.
Be mindful that depending on the pulley and the 3G you might need a shim washer behind the already short pulley.
Here, 5/8 washers are a sloppy fit, enough that our 16mm equivalent (5/8") will fit fine over a 17mm shaft.

Any more questions?

[85lebaront2]

The 130 amp can be found on Taurii with the 3.8L V6 that is a pretty good fit on our trucks. If you are getting one from a junkyard that allows you to pull your own parts, get as much of the alternator harness as you can.

[ArdWrknTrk]

The 3.8 has the 8.25" C-C
The 3.0 is 7"....

[BigBrother-84]

Gary — About the harness.

I took couple of minutes to examine it.  I jumped back to the Rethinking The 3G Conversion Pages/Process thread, and trying to figure out where each terminal has to be plugged.

Need some light.

Here is a diagram of the harness.  My questions in purple:
• The alternator plug (just curious ), which wires (gray, yellow) are connected together?
• Where to connect the choke heater?
• About the Voltmeter connection (sorry, you'll feel as repeating, I apologize)?
• The two yellow wires are to connect where?

Thanks!

[Gary Lewis]

Jeff - This is the key schematic.  It shows how you are to use the harness I sent.

But let me try to address your questions as I understand them:

Voltmeter: You don't do anything but change out the ammeter for the voltmeter.  The C610 connector in the harness I sent is wired to send key-on power to your voltmeter on one side and ground the other side.

Choke Heater: Your Wh/Bk wire connects to the stator terminal on the new 3G.

Y/LG: This wire has an eyelet on it and it'll go to a screw on the fender to serve as ground.

Y/Wh: This wire should also have an eyelet on it and it goes to the same terminal on the megafuse holder that the Bk/O wire goes to.

Does that answer your questions?

[BigBrother-84]

I continue my investigations, preparing for future 3G swap.

After job, I went to Big Bro's garage and looked under the hood to identify the different places where the new harness will plug.

Friends, I'm probably blind, but I do not see the C610 connector.  Where should I look?
As Jim pointed here, seems that there is couple of possibilities...