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About to do the 3G swap, a few questions still

 
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Old 04-24-2014, 02:26 AM
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Question About to do the 3G swap, a few questions still

Well after holding off for a long time I decided to do the famed 3G swap on my truck. I did a lot of reading on here and FSB and got enough info (or so I thought) to do this. I am pretty positive on 98% of what I need to do but there are still a few things that are not solid.

First off, I went to the local junkyard today and picked up a 3G alternator from a 90s Ford Taurus for $25. However once I got home I decided to take a closer look. The case does show some signs of wear, but it does not look really trashed from what I can see, so it should be good there. I also spun the pulley by hand several times and I can hear a good deal of squeaking coming from it. Is there anything that is wrong with this alternator that should prevent/dissuade me from installing it? I really don't want to get a lemon alternator and swap it in now, and wind up having to replace it within a few months. (I know that squeaking is bad- but otherwise I know very little about them which is why I ask) I am unsure at this point whether to try and rebuild this one (I imagine that there is probably parts that need replacing in there, especially with it squeaking as it is) or if I should bite the bullet and buy this bad boy High Output Alternator, 200 Amp, Serpentine Pulley a 3g alternator from JBG which is already clocked for my engine and everything, plus pulls 200 amps vs the one I currently have (130 amps.) Now at about $240 it does have a rather hefty price tag, but not as high as some I have seen, plus it is brand new and is rated at 70 amps higher than the jy one. I am leaning towards rebuilding the one I have ($25 plus another 50 or so for a rebuild kit still puts me way ahead of the $240 for the JBG one) for obvious reasons, but I have no idea if its actually worth rebuilding this alternator or if I should just buy the JBG one or a new Taurus alternator for more $$$???

If I do decide to rebuild the jy one I have, what parts would you recommend I replace on it? Links to them would be extremely helpful. I figure that the brushes, bearings, and voltage regulator could be/is bad. I did find this rebuild kit Alternator & Starter Parts Wholesale - REPAIR KIT-FD 3G which includes all the above. I also found this site Alternator & Starter Parts Wholesale - Ford which advertises a lot of rebuild kits, but they are rather pricey I think.

Final question (I hope lol) is about the wiring. The car I pulled it from I was not able to get any of the wiring needed/preferred. I saw this http://store.alternatorparts.com/par...ternators.aspx which looks like it should be (almost) plug and play. Sadly with RJM out of business, there is not a lot of wiring kits I can find for these swaps anymore. Does this seem like something decent or should I just go buy wire and make it from scratch? If I do get this kit, what else will I need to do in terms of wiring?
Sorry for all the questions guys- I swear I'm not a total noob at this. I'm pretty solid with a lot of mechanical stuff but wiring confuses me some lol I apologize if I was unclear (typing this up at 2AM) and will clarify if I need to. Anyways thanks in advance and as always
 
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Old 04-24-2014, 08:17 AM
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I'm only speaking for experience of just doing this upgrade, and I know that there are a lot more experienced users on here, but here is my two bits.

I don't know much about rebuilding an alternator, but take the one you got into a local parts store. All the ones in town here will test them, easy cheap way to know if its good or not.

As for the wiring, I got lucky I guess and got both connectors with the alternator I picked up. Wiring was for me at least, incredibly easy. On my 1987, I believe there were just three wires coming from the alternator to hook up elsewhere in the engine bay. Looking at that link, it looks exactly like the harness I made for my install. Only other thing I had to get was new cable to run to the battery and a fusible link to put in between the two.

There are several write-ups on here about the process and are easy to follow.
 
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Old 04-24-2014, 11:37 AM
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If it were me I would take that alternator to a parts store and use it as a core on one of theirs. Oreilly's has a rebuilt unit for ~$130 that carries a lifetime warranty.

As for the wiring, the cheapest option is going to be going back to the junkyard and getting the regulator plug off of a 3G vehicle. Once you have that you just cut the old 2G plugs out, wire the new one in, install the alternator and run your power cable. You need about 3-4 feet of 2 gauge cable, a 175A MEGA fuse and holder and some cable lugs for the ends.

Here are the NAPA part numbers for the fuse and the holder:
Fuse: BK 7821139
Holder: BK 7821143

The other thing you might find with your alternator is that the clocking is off for the regulator plug. If so here is how you change it:

"Onto the reclocking process - you need to first pull the voltage regulator out, 4 torx bolts for this, and you do it just so the thing gets out of the way. Then you put a large screwdriver or a small prybar between the rear cover of the alternator and the rectifier chassis (the big black center ring with the vent holes) - you need to pry the rear cover off the rectifier chassis, do so very carefully as the alternator's rear bearing is pressed into the rear cover and will need some persuading to make it pop out. When the cover comes off, the bearing stays on the shaft. And now comes the fun part - making the stator coils armature let loose of the alternator case. While it is tempting to pry between the rectifier chassis and the main case of the alt, do NOT do that - the rectifier is riveted on its chassis and is attached to the stator coils with 6 solder joint, by trying to pry the rectifier chassis off the alt case you're essentially trying to pull the whole stator armature by applying force on these 6 solder joints, and it is very likely that you will damage them in the process. What you can do instead is what Sassyrel suggested - take a hammer and tap on the case. In my experience a plastic hammer will not be enough, you need a metal hammer for that, albeit a small one - just don't smack it very hard and there will be no damage to the internals. If you're lucky the armature should let loose after a few hammer taps, then you can turn it how you want it - I prefer 1/3 turn clockwise if you're looking at it from the back of the alt, this positions all the wire connectors right on top of the alt. If you're SOL tho, the armature may not come loose even after some good smacks with the hammer - this is when you have to take a long but thin drift punch and reach through the cooling vents in the front of the case and drive the armature out, but this is a very delicate job as that's also right where the stator coil windings are and it is very possible that you damage some of them in the process - if you've never done this before, I suggest you practice on your old alternator first, and if you still don't feel confident in it just run the alternator as is and install a slightly longer belt to keep the electrical connections away from the thermostat water neck and the upper radiator hose." - LCAM-01XA over @ Oilburners.net.
 
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Old 04-25-2014, 12:18 AM
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Thanks a lot both of you y'all were a big help :-) I did what you recommended Evan and picked up the alternator, the mega fuse and holder (part # was very helpful btw, the guy at the counter wouldn't have been able to find it if I didn't show him that lol) plus a harness for the Taurus/alternator ($10 brand new) plus some 4ga battery cable. That 4ga is damn big wire but I will probably go out tomorrow and get 2ga though just to be on the safe side. I hope to be able to get this thing goin and in on the weekend if all works out. Thanks again guys I'll be sure to post updates along the way! :-)
 
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Old 04-28-2014, 10:37 PM
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So just a quick update. I got the alt wired up and mounted and the truck runs just fine. However I get the amp warning light on all the time, and the gauge on the dash always reads about 10 (right on the N) all the time. Now I know from reading on other swaps that this will make all the idiot lights and stock gauges for this irreverent, but I always assumed it wouldn't even read anything and right now it's reading 10. I did go to a store to have it tested, and the battery read 12.3 volts while it was shut off. I'm figuring that this is just one of these things where the alt kinda has to "break in" a little bit before it will charge it all good. Anyways, I guess I'll know when I go to start up the truck in the morning. Thanks to FTE I was able to do this awesome swap!
 
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Old 04-28-2014, 10:58 PM
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12.3 volts resting is low. I would have that battery load tested.
 
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Old 04-28-2014, 11:06 PM
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Originally Posted by Evan_P View Post
12.3 volts resting is low. I would have that battery load tested.
That's what I thought, and I went to have it tested about an hour ago. According to the guy, the battery read that it was still good, but in need of a charge. That brings me to wondering if either my battery is goin bad (it's 5+ yrs old, or I screwed up somewhere in the wiring.) For the wiring, did you find that you needed to run a ground wire from the rear of the alt to the truck like described in the wiring diagram? I've heard some people did and some did not- curious as to which is the "right way" per se. That's my best guess if something is in fact up with the wiring. Then again what do I know lol
 
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Old 04-28-2014, 11:43 PM
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All I did for mine was clean up the alternator mounting points.
 
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Old 04-29-2014, 12:27 AM
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Now that is one thing that I do have to do for sure. As encountered by some other posters, the 3G alternator didn't clear the bracket all the way and did not fit quite right to enable me to bolt the top bolt on it. It was bolted through the bottom, but the top hole and the top hole on the alt bracket were about 1/4" off still. I was pressed for time however (had work in less than 30 minutes) so I plugged it all in and went. Over the weekend (or whenever I get a couple spare hours) I plan on grinding the bracket so the alternator will fit in there properly, and swapping the pulley from the 2G to the 3G plus the spacer as well. The belt does not squeak at all, but the low charge makes me thing that the belt may be slipping a bit and if so, hopefully swapping pulleys on the new alt and getting the alt mounted properly will change that.
 
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Old 04-29-2014, 02:49 PM
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Update: started tracing potential problems this morning. Hot wires from alt to starter were lose on the fuse, so I tightened up the connections hoping it would fix the issue (as I know of someone else who had similar problems on this forum that was solved with that.) Later today I bought a voltmeter and tested the battery. 12.1 volts when off and 11.33 volts at idle. So apparently it didn't fix the issue and something is definently wrong. Saturday night/ Sunday when I get some time I will go through the system with a fine tooth comb and hopefully figure out and fix what's the problem.

Will try to ground the alt to the chassis next. I know it should ground on thr bracket but since it isn't 100% solid on there yet. I hope that grounding the alt to the chassis will fix my charging problem.
 
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Old 04-29-2014, 04:24 PM
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Sounds to me like the alt isn't working at all. If you don't have the right size pulley on there it's probably not turning fast enough to generate enough juice. Maybe you could play dumb and take it by Autozone and have them test the alt while it's on the truck?
 
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Old 04-29-2014, 07:01 PM
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Originally Posted by cman1120 View Post
Update: started tracing potential problems this morning. Hot wires from alt to starter were lose on the fuse, so I tightened up the connections hoping it would fix the issue (as I know of someone else who had similar problems on this forum that was solved with that.) Later today I bought a voltmeter and tested the battery. 12.1 volts when off and 11.33 volts at idle. So apparently it didn't fix the issue and something is definently wrong. Saturday night/ Sunday when I get some time I will go through the system with a fine tooth comb and hopefully figure out and fix what's the problem.

Will try to ground the alt to the chassis next. I know it should ground on thr bracket but since it isn't 100% solid on there yet. I hope that grounding the alt to the chassis will fix my charging problem.
I would put my money on a problem with the green/red exciter wiring. There should be 12VDC whenever the key is in the Run position.

 
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Old 04-29-2014, 08:34 PM
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That would be my guess as well.
 
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Old 04-29-2014, 08:57 PM
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Thank you guys for the advice I really do appreciate it :-)

Funny story is I was on my way home from work when all the electronics of the truck started shutting down. First lights radio ect then abs sensors then the odometer then the speedo and finally the tranny and I coasted to a stop at a light. Used my mini generator I keep for times like this to jump the truck and I got one block. Now I called the old lady and am getting a jump as we speak. Hopefully it'll charge the battery enough to get me the rest of the way home. If not then I'll have to get creative lol! I will be sure to check all the wiring when I get home as I bet something is loose/not hooked up right. Gotta laugh lol. Thank you guys for the advice I really do appreciate it :-)


Sorry double post arg this phone! (Fixed : Encho)
 
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Old 04-30-2014, 02:29 AM
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Pictures, pictures!!!

I'm looking to do the same 3G swap as well.

I've read a lot but am still unsure, but this helps
 

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