3G Alternator or something else?

[3Kp]

I have notice my battery light is lit up the dash. Haven't tested anything yet to see what's causing the issue. (thinking alternator)

I have noticed looking on line at alternators anything over 70 amp has 6 groove pulley. 70 amp or less has 2 groove pulley I believe I can change the pulleys with our causing issues. Also noticed at night for quite sometime that when I have RPM's higher then idle the head light are brighter.

I was thinking of putting on a bigger alternator at least 100 amp. I have noticed people mentioning the 3G alternator (which I believe it comes out of a Taurus? Which years I'm not sure) From what I understand the 3G is only a 130 amps. While I was researching I found a 165 amp alternators for the 7.3 idi ambulances.

Here are my questions

Do I really need anything bigger than 100 amp?

If I installed the 165 amp would it hurt anything?

With the 165 amp would I have to rework the wiring like on the 3G?

Thank you for your time and information.

 

[Black dawg]

There is a 100 amp version of your stock alternator available, but the 3g is a better alternator, and the wiring is very easy.

Even the best stock replacement alt I had on my truck (100amp) would stay well under 14v after a cold start for several minutes. With the 3g that has been on there a month now, voltage is 14.5 v before the engine has even smoothed out from a cold start.

 

[typ4]

^^^^^^^ I second this exactly.

The 165 is a leece neville, do not use, it is not readily available. Rebuilders from AP stores dont know how to do one right. the 130 amp 3g is a kick ass swap.almost a bolt in.

 

[dunk]

This is the alternator I run, application for a '95 E-150 4.9... http://www.dbelectrical.com/p-8304-alternator-ford-f-series-truck-49l-94-95-96-75l-95-96-97.aspx

130 amp 3g, wide ears, clocked in best position for wiring to drivers fender/battery/etc. Just needed the alternator a 3g plug/harness, mega fuse+holder, and some 4ga wire. I upgraded because my factory 70 amp was giving me grief. Realistically a 42 amp 1g would run these trucks just fine as there is very little amp draw when running and as long as it runs a bit and not stopping and starting all day long. If you don't have some additional higher amp electrical load then the only reason to upgrade are for less/tidier wiring, or if your factory alternator is failing and needs replaced. I would not run another 1g/2g/other oddball alternator again. 3g is a cheap and easy upgrade, worth doing if your replacing an alternator anyway.

 

[tnthielen]

Hey Dunk,

Just curious as to where one might find a 3G plug/harness that is new as opposed to a junk yard? Also, what size/type of "mega" fuse should be used? I'm kind of new to this and I'm going to be replacing my alternator soon on my project truck, so I'm extremely interested in upgrading my alternator.

Thanks!

-Todd

 

[3Kp]

Dunk

That's a good price $80.00 I was looking locally at 100 amps $100+ The 3G plug/harness is obtain in the junk yard or is it available new? (if junk yard find how will I know if i'm getting a 3G harness or is it pretty obvious

 

[junk]

I bought a 3G harness online. Included the plug and power wiring with fuse holder. It was pretty slick and not badly priced. Maybe 30 bucks. Hit google for "3g alternator harness" and they'll pop up like cat videos. The are really popular on mustangs.

- Jeremy

 

[ironworker40]

Db electric has one wire 3gs up to 200 amps and a cable and fuse kit to install them. No plugs to get and and only one wire. They will put any pulley u want on them to. Seems like an easy way to do the swap.

 

[junk]

I'll second DBelectric for starters and alternators. Only place I get them anymore if I have the time to wait for shipping.

 

[Zaggnutt]

I want to have this swap done for snow plowing season. Looks like you guys covered everything. Great thread, thanks!

 

[ironworker40]

I did the 3g 130 amp swap on a 88 gasser plow truck. Replaced the 70 amp 1g. Never had a charging problem for the next 5 year till I sold it.

 

[3Kp]

Today I finally had a chance to test out my charging system. The voltage regulator was bad.. So no 3 G alternator yet!

I'm glad I bought my Ford dealer service manuals.

 

[icanfixall]

So your v r was bad.. Is that the separate one thats on the fender well? If so nice easy repair. Heres a note about any alternator. Their design is to "refill" the batteries after a start. Once thats done the now become the supply system for every electrical drain on the car, boat or truck. We could not drive very far is we depended on the stored battery charge thats for sure. Actually an standard trans truck can live a long time running on low batteries. All we really need is about 9 volts feeding power to the fuel shutoff solenoid. And if we had a manual valve there we could run till we ran out of fuel, engine oil or coolant. Once a diesel starts up it does not need any electrical source to keep it running... Unless its a newer all electronic engine. Also a 200 amp alternator will have 3 coil terminals where anything else has 2 coil terminals.

 

[Kevin 007]

Do any 3Gs have a cooling fan on them like the 1 and 2 G's???? I bought a 3G for DB electric that im going to install a V belt pulley on and toss it on my 84 soon and I have a couple used ones around also. None have fans. Dumb question but I thought I would ask

 

[dunk]

Fans are internal on 3g.