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Discussion Starter · #1 ·
Hello all,

I am getting ready to do this upgrade and have been reading the tech threads on this. My alternator is about to take a dump and I am not replacing it with another stocker.

I just wanted to clarify a couple of things before I tear into this.

So I have a 91 with a 302, so that means I am after a 3g with a 7 inch ear spacing (below) correct?


I understand that I will also have to do some grinding on the bracket as well.

as far as wiring in the new 3g that seems pretty straight forward.
yellow goes to the output post
white goes to the middle tab
green goes my old switched 12v source

I have a question about the original wiring and what stays and what goes, according to these diagrams posted by Fireguy there is a "splice" that is on the orange/black line in the original wiring that is no longer used after the conversion. So what do we do to this splice ? just cut and tape it ?

also, where is this "fuse link" that ties these several wires together ?

Thanks in advance for any tips, I am planning on tackling this this weekend.
my alternator now can barely handle headlights and a blinker at the same time.

2g wiring
Before:


After:
 

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I used the following parts on my 1990 351w.

RJM Injection Technologies 3G 160 Amp Alternator/7” Pivot/Clocked to 4:00
RJM Injection Technologies 3G Alternator Harness
RJM Injection Technologies 2¼” 3G Alternator Serpentine Pulley
RJM Injection Technologies 2 Gauge Heavy Duty Alternator Charge Cable w/175A Mega Fuse

The RJM 3G Alternator Harness made it a very simple install.





 

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Discussion Starter · #4 ·
Got all my parts needed for this today at the JY. with the exception of the fuse holder, I have a working 3g and several 175 fuses.

the problem is though that I need to reclock the alternator.

Is it as simple as removing the 3 bolts and sliding to the position needed? or do I have to take it all apart, I just worry about messing up the brushes if I take it apart.

Thanks
 

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'88 XLT. 2" lift, 3G, Saginaw Pump, Headers, High flow 3" cat, 3" exhaust, 6 litre tune, K&N
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I am assuming your big power lead is at 6 o'clock. I made mine work in the 6 o'clock position by just bending the O terminal so the wire is 90 degrees to the alternator, and used heat shrunk tubing and a wire loom for security. Attach the wire before installing the alternator.

I wasn't aware I can reclock this, but am now please post pictures if you do yours.
 

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Discussion Starter · #6 ·
I am assuming your big power lead is at 6 o'clock. I made mine work in the 6 o'clock position by just bending the O terminal so the wire is 90 degrees to the alternator, and used heat shrunk tubing and a wire loom for security. Attach the wire before installing the alternator.

I wasn't aware I can reclock this, but am now please post pictures if you do yours.
yes, mine is at 6 oclock as well. I made it work but not the prettiest.

You have to either pull the VR, put the brushes back in & pin them, then clock the rear case w/field, put it all back, & pull the pin, OR; pull the pulley, push the shaft in to keep the brushes on the commutator, clock the front case, & put it back together.

.

thanks Steve, I may give that a go next weekend. sounds like taking the pulley off is the easier method. I needed my rig back together asap so I threw it in as is

overall it went well just like the 3g tech writeup is. although I had to grind a little bit off of the bottom of that top bolt bracket right below the hole, otherwise my alt couldnt fit back far enough to line up the bolt holes.

I am holding at 14.5 volts with literally everything on in my bronco. Great upgrade.
 

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Discussion Starter · #7 ·
question for everyone that has upgraded to a 3G, did it make any difference to your gauge ? my does basically the same thing as it was before, I figured it would be higher on the 'normal' scale
 

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seattle I think that alternator is clocked to 8:00.
4:00, looking from the back. 8:00 would be to the lower left. Go to this link and click the "more images" mid-page.

RJM Injection Technologies - 7″ Pivot 160Amp 3G



To determine the clock position, view the alternator from the back with the mounting spool at the 6:00 position. The location of the regulator terminal determines where the wiring harness attaches to the unit.

 

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My gauge read higher than my 2G, but the original alt was in bad shape from running my plow. I just went down to Napa for the Mega fuse holder and fuse instead of ordering it. The harness from RJMinjectiontech worked great and I was able to delete all of the original harness except the grn/red wire.
 

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Discussion Starter · #12 ·
My gauge read higher than my 2G, but the original alt was in bad shape from running my plow. I just went down to Napa for the Mega fuse holder and fuse instead of ordering it. The harness from RJMinjectiontech worked great and I was able to delete all of the original harness except the grn/red wire.
yeah, its wierd cuz my lights dont dim or my fan doesnt run low, like it did previously with the 2g but my gauge didnt really react to the swap.
 

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Discussion Starter · #13 ·
The voltmeter shouldn't change at all, other than NOT dropping as much under heavy loads. The 2G regulator is either the same, or virtually identical to, the 3G VR.

The pulley requires an impact wrench - pulling the VR is easier, IMO. ...and I have several impacts.
ya, mine still drops, I must have a crappy ground or something
 

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My gauge reads the same, except when I have the lights, wipers, stereo up, defrost on, then I read over 13 volts instead of 12 volts with the 2G. The biggest drop for my gauge is the rear defrost.

Pull and clean all the O-terminals on your starter solenoid. You might of moved them a little tightening the new alternator lead and got a worse connection from corrosion on the terminals. Clean the terminals on the battery and check the grounds to body.
 

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Discussion Starter · #16 ·
weird, I just did a load test

battery -12.8 volts
running with nothing on - 14.45 volts
running with everything on - 14.3 volts (heater, defrost, lights, radio)

those numbers look good right ? for a 3g

all of my accessories barely drops the volts, but my gauge will drop pretty good when I have all of the accessories on. so my problem must be isolated to just the gauge, not a big deal but intresting how the gauge drops so much when there really is no drop at all.
 

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Discussion Starter · #17 ·
holy crap, how do you know all of this stuff ?

how does one check resistance ? thats OHMS on a voltometer right ?

Or I guess after reading your folder, I can have Ford take a look at it
 

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Discussion Starter · #20 ·
I figured I would update this thread , that junkyard 3g I installed in 2012 (this thread) just crapped the bed yesterday.........not bad for ~20 bucks and a half hours time. One of the best upgrades I have done to my Bronco.
 
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