3g alternator swap
 

Just finished swapping in the infamous Ford 3G alternator into my 1987 Ranger. I'm actually quite surprised this swap isn't a little more popular in this forum, but enough rambling of that sort...

I wasn't experiencing any "real" difficulties regarding the OEM 2G, however, I plan to swap in a Mark VIII electric fan which requires 90+ amps, and the OE 40 amp just wasn't going to cut it.

http://i1211.photobucket.com/albums/...r/IMG_0505.jpg

Plus, with the onset of colder weather (I have only had the truck since April) I have noticed dim lights and a slower heater fan when at idle. The 2G was struggling. Not too mention the bass-ackwards way Ford wired in the alternator circuit.

The main issue I saw with a 2.9 set-up was the strange off-set ear alternator and really short alternator bracket. I was figuring on just extending the bracket to accomodate the normal 3G pattern... until I came across a 2.8 Ranger at the junkyard. Low and behold a normal alternator bracket. Snagged that and it worked just fine with a little grinding for alternator clearance.


http://i1211.photobucket.com/albums/...r/IMG_0507.jpg

The only other issue was the pulley. Very minor, and something I encountered when swapping the 3G for the 1G in my 74 F100. When installed on the 3G there is very little thread left for the nut. No biggie, just grind down the central "nub" until it is flush with the face of the pulley. Make sure to use the spacer from the 2G behind the pulley as well.

Bolt it all together and now run the wires.

Yellow goes back to the charge post. Connect the red/green with the original red/green. I disregarded connecting the OE charge wire or the white wire.

Run the charge cable to a 175 amp megafuse. I took advantage of the plastic inner fender and installed some bolt studs for mounting points. I also ran the original fusible links to the fuse instead of cluttering the solenoid any further. And then of course run another charge wire from the fuse to the solenoid.

http://i1211.photobucket.com/albums/...r/IMG_0508.jpg

Done and done.

Smooth, quiet, 14.5 volts and no lag at idle with headlights and heater on high.

Super easy swap. I will likely swap to a slightly longer alternator belt to get the alternator away from the engine and filter more, but it's fine for now. I will also fabricate a cover for the fuse junction after I rig up the electric fan relays.

Josh

Looks very nice.. i have been planning to do somthing similar on my 88... i did'nt know about the 2.8 bracket fitting a "normal" alternator... Very imformative post. They should make this a sticky..

I am glad on stumbled across the 2.8 bracket. I was figuring I would snag a second 2.9 bracket and extend it, which isn't a big thing to do. But the 2.8 bracket is almost ready to go, except for a little griding to clear the ALT case.

Josh

did you also use the bottom alt. bracket off of the 2.8? i snagged the top one at my junkyard today.... also what type of vehicle did you get the 3g alt from? i got one out of a late 90's early 2000's taurus 3.0L...was a reman'd alt that looked pretty decent, and turned smooth and quiet.. i just hope it's good..

Early 90s Taurus/Sable is where I sourced my alternator.

Yes, stock lower bracket. Mock it up and you should see where the upper bracket will need some grinding for clearance. Also you'll notice where the stock bracket was use the the extra bolt hole just above that.

it looks like the ears/bolt holes on your alt. are spread out further than on the one I have.. I will try to test fit it tomorrow, and see what i've gotta do to make it fit..my truck has a 60A 2g on it now.. but it's an STX with the light bar and the brush guard fog lights..i also have an amp in the truck..as well as A/C.. 60A seems a bit small for what this truck has..when i had my old 1990 F250, the 75A 2g would stress out powering just the A/C and headlights. i'm sure this 60A is REALLY stressing..although i've never had any dead/low battery problems..just the headlights going a little dimmer and the A/C blower slowing a bit at idle..hopefully the 3g will solve that..

I had a 40 amp that could barely handle headlights and a heater, I couldn't imagine also having a/c and a stereo system.

Not too mention the puny small gauge charge wiring from the 2G alt that goes thru the entire wiring harness, thru the cab and. And back to the battery. No wonder it doesn't really charge and on some catches fire.

Josh

i still haven't had a chance to test fit the alt. again.. work.. bleh...
i've also been wondering about an E-fan setup, like what you're going to use..would that e-fan move enough air for the engine, and the A/C in 110+ weather? I live in Phoenix, and the summers here are brutal..the engine fan creates a pretty good drag on the engine.. but it has to in that type of weather..i wonder if an e-fan would work better, and take some of the load off of the engine? I used to have a small 10" pusher infront of the A/C condenser, that only came on when I had the A/C turned on that worked well, it helped the A/C blow colder at idle/slow speed.. but the motor died on it..why I don't know.:-huh

I plan on using the infamous Lincoln Mark VIII 2 speed electric fan. I used that fan on my 1974 F100 with a 500 horsepower dual quad 428. With temps 95+, the low speed was more than adequate in stop-n-go traffic keeping temps right at 200.

The MarkVIII fan moves a ton of air. And that is just low speed, I never had to use high speed once. You have to figure, if it cools a V8 in a 2.5 ton car grandpa putz around in, it should cool a small Ranger likely too much.

But, it's what I do, change stuff.

I'm not exactly sure when I will swap in the fan. I hope to make the brackets in a couple weeks, the wiring is a cinch. I'll do a write-up, but essentially...

I'll have an on-off-on toggle for automatic low speed, completely off and manual on for high speed.

Use a Ford Tempo temp sensor for low speed. 205 degrees on, 185 off. Stock 195 t-stat.

Bosch 40 amp relay for low and a heavy duty continuous duty solenoid for high. The fan draws upwards of 90 amps on high speed, the main reason for the 3G swap.

I have various threads over in the 73-79 forum of the MarkVIII swap. Definately the way the go to cool an engine and help the MPG with the engine fan eliminated.

Josh

I know this is an old post, but I installed one of the small case 3G alternators on another 87 Ranger recently. It worked the same using a 2.8 upper alt bracket. It also needed clearancing to clear the case. Plus I had to do a touch of grinding on the actual 3G case to clear that bracket. I could have taken more off the bracket, and would likely do so if I did another swap with the small case.

But it worked. Either small or large case works fine, but if given a choice I would tend to lean towards using the large case.

Josh

I know this thread is a bit old but, the alt on my 87 B2 is dead and this looks like a nice upgrade. I already have the 2.8 bracket, but what engine did you pull the alt off of? Also could you post more pics if the wiring?

Thanks

Early-mid 90s 3.8 v6 Ford Taurus is the easiest to find.

Josh

Did you use both the lower and upper 2.8 bracket. If I just use the upper, there is a gap between the top mount and the upper bracket. But if I use both the upper and lower the pulley is offset.

Just the upper mount.

Josh

Did yours have a gap between the back of the bracket and the alt?