I want to do a 3g alternator upgrade and want to run dual vbelts off of it.
I have the 1st crank groove going to water pump and power steering and the second currently going to my alternator. 3rd groove is empty but slightly different in deepness of the groove.

Is there a factory crank pulley that has the last 2 grooves the same as well as an alternator pulley with 2 grooves i can pull out of a Junk yard?

 

Where are you located ?

 

Yes. An 86 302 with EFI had exactly the pulley you are talking about. I know because one of our guys (Ray1986F150) left his truck here last winter and I checked the pulley out - exactly what I wanted to do what you are doing. I posted about it here, but still haven't figured out the part # of that pulley.

Perhaps NumberDummy can help me understand what I discussed in that thread?

By the way, here's how I'm going to do it. The idler pulley is a combination of the pulley from a 460 with a serpentine system, and it is mounted on the standard idler bracket for an M or W.

 

wow thanks. now to clarify the pulley you are talking about is the crank pulley with the 2 outer most grooves the same correct? now how about the pulley for the alternator?

and to answer bruno im in Louisiana

 

Yes, it is the crank pulley I was talking about. I need one as well. But the parts catalog is quite confusing so I haven't figured out exactly what vehicles it comes on besides the 86 EFI'd 302 I found it on. I will try to get clarification.

As for the alternator pulley, these people have everything needed to repair or upgrade alternators, inc pulleys. The 3G I got from the salvage has at least one bad diode so I'm going to use their 160 amp diode bridge. Plus a new LRC regulator so it won't squeal the belts on startup.

 

Gary,
You're running dual belts.
Traction shouldn't be an issue.

My truck came with a 2G alternator driving dual air pumps.
It has a dual sheave pulley with 10mm(?) belts.
Swapped right onto my 3G with a thin shim washer behind it.

 

True, but I'm going to be replacing the regulator so why not go LRC? It is the same price as the one w/o LRC. So, why not?

 

Absolutely no reason not to.
Just that your point about chirp or squeal is pretty much moot with dual belts.

 

Oh. Ok. Got it. I do have some other questions about regulators but will ask this in my thread so I don't hijack this one.

 

Gary,
I tried the idler pulley set up you have on my 86 460, it would spit the belt off at idle . I used the same idea except with a "V" pulley underneath the belt and it works fine.
Rodger

 

So, the V-belt pulley worked better on the back of the belt than a flat pulley? That's strange. Do you think it was that the flat pulley is too wide and let it walk?

Also, some have said that most v-belts aren't made for wrapping backward. Did you use a standard belt? Have any problems?

 

Gary,
I used a NAPA stock replacement belt, the flat pulley on top of the belt had the belt going on to the AC pulley below the centerline of the AC pulley. I used the same idler type system you have with a V belt pulley. Have not had any problems. You just have to make spacers to align the V belt idler with the other pulleys. I started with 1/2" thick spacers and adjusted from there.
Rodger

 

Interesting. I don't want to hijack this thread, but you now have me worried that my arrangement isn't going to work. Guess it is back to drawing board.

 

A bearing/power transmission salesman told me once that a lawnmower belt IS designed to run on the backside, and that's why they are usually more expensive than a regular v-belt. If you were worried about it you could look for a lawnmower belt that might fit.

 

So it was you, Dave, that told me that. I will keep that in mind. Thanks!