View Full Version : Alternator pulley problem

07-06-2013, 10:52 PM
My alternator on my 40 died and the replacements are all disco'd. I could have mine rebuilt to the tune of $500-600 or I could adapt the truck to take a "modern" alternator. I decided to try the later path first, but I've run into a snag. I'm okay with fabricating a bracket, and I'm okay with making an adapter harness to wire it up. My current issue is the pulley. I didn't notice in the pictures of the new alt that the v belts were TINY compared to the Toyota stuff. So I need to figure out how to get a proper pulley on there.

Option A: Make of find a sleeve that will adapt my Toyota pulley to the smaller and longer shaft of the Isuzu alternator. Sleeve would need to be somewhere close to 16.8mm ID to 19.8 mm OD. I found a 17x20mm bushing on McMaster, but it would likely need to be machined a bit and will have a tiny bit of play.

Option B: Find a different pulley that fits the Isuzu shaft, uses the appropriate sized v belt, and aligns fairly well. Since I haven't finished the adapter, I can adjust the alignment if I need to.

Option C: Make a custom pulley. I really don't want to go this route, however, I could make a dual V belt and be able to adapt a York on there later if I really wanted to.

Anybody have advice and/or resources to do this? I need to get this back on the road and have yet to find a quick & perfect fix for this.

07-07-2013, 01:55 PM
Is this for your 13BT?

07-07-2013, 10:33 PM
Sort of. On the 13BT, but it's an Isuzu NPR alternator. I "think" I found a source for a pulley for a reasonable cost. We'll see...

Air Randy
07-08-2013, 11:40 AM
As long as the pulleys line up correctly, you can use the smaller V belt that fits the alternator in the larger V notch of the Toyota crank pulley. It will just run deep inside the pulley but should work fine. I've also seen people runner the wider V belt in the smaller V pulleys, it just wont fit flush with the pulley sleeve.

07-08-2013, 10:09 PM
I may have it licked. Vanetta electric called and said they have a bushing for that so I can use the toyota pulley. I just gotta get up there to check it out.

07-11-2013, 11:41 AM
Update: He did "make" a bushing for it, though not at all what I asked for, completely overpriced, and copped a serious attitude with me in the process. That guy may know his stuff at some level, but I won't be going back regardless. I still struggle to understand how even in this economy that some small shops treat paying customers the way they do.