GM alternator pulley for Toyota wide belts (1 Viewer)

[TRAILTOYZ]

I picked up a new pulley for the 12si, 78a alternator I'm putting in my '75 FJ40. I thought I'd toss this little tidbit into the plethora of tech which currently exists on this very issue.

Bought it on Ebay from triodiode for $17.20 shipped. Info from auction is below.

Search for: Alternator Pulley 5/8-3/4 Delco Conversion

Info: Ok you changed your generator to an alternator and now the belt won't fit. Here is a 5/8 and or 3/4" width pulley with nut that will fit Delco Motorcraft and others that use a .67 ID pulley. This is a conversion pulley with a .67" ID 2.5" OD. If you have a Delco alternator and it has the old style fan with a cupped center like the fan on the right you will need a different fan and spacer for this pulley to work. If you do have this style let me know and I will send you one (used) free. You pay the extra shipping. The pulley itself will ship for 1 pound with the fan 2 pounds.
Stock # 01005

 

[Poser]

I have used a Toyota pulley on a GM alternator many times.

 

[TRAILTOYZ]

I thought about doing that, but going with a smaller pulley increases RPM/output of the alternator to generate more current at idle...figured it would be a welcome upgrade when winching, etc.

 

[tuolumnejim]

Both of the pictured fans are wrong for a 12SI and couold lead to overheating of the unit. This from the FAQ, here.

Notice in the photo, the fan and the alternator end frame both have “ridges,” where they will mate to each other. (The ridge at the fan fits just inside the ridge at the alternator case.) The effect is like a shroud, or like a seal, which will only let the fan draw air through the alternator. (This fan cannot suck “outside” air from near the front of the alternator–the fan can only draw air through the alternator.)

 

[mr_manny]

I thought about doing that, but going with a smaller pulley increases RPM/output of the alternator to generate more current at idle...figured it would be a welcome upgrade when winching, etc.

x2 on the toyota-12si pulley swap.

If you have a chance, measure your voltage at idle and say 1K to see if it's worth it?

 

[bsevans]

This is the double pulley that comes on the Mean Green. Both pulley grooves line up with the crank double pulley grooves.