This thread is an AMAZING source of info; the bible for a 3G swap:
http://fullsizebronco.com/forum/showthread.php?t=55169
While much isn't applicable to the XR, the basics are. I had already relocated my alt to the A/C location using the A/C bracket and a turnbuckle after seeing Ray do the same. I wasn't going to reinvent the wheel for this and I would be using the modified A/C bracket that worked with the stock alt:
The ears on the factory alt are spaced 7", which also happens to match one of the styles of 3G alt. Per the thread above, this can be found on:
- 93-99 narrow-eared non-DOHC Taurus
- 94-95 V8 Mustang
- 94-00 V6 Mustang
- 94-97 V6 T-Bird/Cougar
- 95-98 Windstar
- 91-94 V6 Lincoln Continental
All easy to find cars in the yard, especially the Taurus which only took me 30minutes or so to remove. The Mustang I found looked even easier, but the pulley was seized so I didn't get farther than removing the belt.
$25 later and a 90-day return policy if bad, I had an alt. Tested fine at Advance Auto and brought it home to start the swap.
Quick zap with the impact and both pulley bolts come off easily:
The pulley from the stock alt, although keyed will fit the 3G alt (non-keyed shaft) without issue. It will need a spacer to keep from rubbing on the case though. The spacer (a washer will work fine) needs to fit the shaft on the alt (.670") but also not be larger than the inner bearing race on the front case. Easy enough, just something to note so you don't ruin the bearing. I used a .175" spacer which was enough to get the pulley off the case with a clearance I was comfortable with. It also gave me enough bite on the threads. I think anything over .300" and you'll be at the limit for still having enough threads to safely bite onto.
Next step was to figure out how to mount this. Thankfully, the A/C bracket can accommodate the larger pivot ear which is 3" in length. The XR alt is 2.25".
And now to figure out how to space the alt in the bracket to align the pulleys. I took a rough measurement to get close and then can fine tune from here. I had the stock alt spaced .400" back from the front of the bracket. The spacing here will of course vary on what size spacer is used to kick the pulley off the front case.
To mount the turnbuckle I wanted to use the factory style of a threaded top ear and stud or bolt. The Taurus alt uses a through hole which is .400" diameter. Perfect for an M12 bolt. Tapped the hole for an M12x1.75 bolt I had lying around. The XR uses a M10x1.5 stud IIRC.
Last step before mounting in the car is the wiring. Very simple, especially if you cut the plug off the donor car. The wiring diagram from the link above explains it pretty well:
Here is how it looks ready to go in the car:
The spade connector will plug into the stock connector without issue. It would look better with a nice, waterproof quick disconnect, but I didn't have any. Easy enough to change later.
Mounting is the same as the XR alt. Hook up the charging wire and the +12v lead to battery.
Done and in the car:
All that's left is to throw a straight edge on the belts to make sure I'm in alignment, get a nice M12 shouldered bolt so I can remove the extra nut and make spacers the proper length to replace the washers used now.
Car fired up and I noticed right away the charging light on the dash went off without a rev. With the stock alt on stock pulleys it sometimes needed a blip and now with the MS cold idle set around 1,200 rpm and the Essy pulleys, the car needed to see nearly 2k to kick the alt on, even after a thorough cleaning. After running for a minute and a few blips of the throttle, voltage at the battery holds between 14 and 14.3v at idle with Essy pulleys. Impressive to say the least.
Cost of the swap...$25. Same belt, same wiring, same pulleys. For the price paid, I don't ever see the need if you have an easy way to mount this to put a stock alt back in the car.
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