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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: AndyyCoulic on April 17, 2015, 09:21:29 PM

Title: Adding belt driven alternator on an 8v71
Post by: AndyyCoulic on April 17, 2015, 09:21:29 PM
I'm looking to add a 24v alternator to my gm 4106 to charge my 24v house battery bank. The bus is 12v so i can't do anything with that.

Wondering if anyone else has added a belt driven alternator to their 8v71 and how they did it? There is a pulley but it looks fairly hard to get at.

Or if anyone knows a way to up-convert 12v to 24v. Saw there are some upconverters but only do 20amps.


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Title: Re: Adding belt driven alternator on an 8v71
Post by: bottomacher on April 18, 2015, 05:31:01 AM
Years ago I bought a takeoff assembly for my 4106 to provide a pulley. If you're interested I will pull it down and take a photo.
Title: Re: Adding belt driven alternator on an 8v71
Post by: OneLapper on April 18, 2015, 05:37:56 AM
The rebuilt 8V71 I bought came from the NY transit authority.  Located over the oil cooler is a bracket that had, what I assume, was an alternator that ran off one of the cam pulleys.  It's under the front exhaust pipe and above the oil cooler.  It's a very tight spot to work in, let alone the fan, torus drive and muffler which will all be in the way.

It might be the same price to just replace the inverter with a 12 volt unit.  It certainly will be easier!  

Anyhow, someone may have that bracket available.  It's not a stock 4106 item.

Good luck!
Title: Re: Adding belt driven alternator on an 8v71
Post by: luvrbus on April 18, 2015, 06:37:52 AM
You have the transmission pump,power steering,air compressor and alternator on the rear there should be a place left for a accessory drive pulley at the rear below the alternator some GM's have it some don't
Title: Re: Adding belt driven alternator on an 8v71
Post by: TomC on April 18, 2015, 08:24:25 AM
I have a V-drive also. I wanted to add an A/C compressor, but the front pulley is just about impossible to get to to build a bracket. Cliffords suggestion on using the lower rear accessory drive is the best. Only thing-might not have the drive gear inside. Good Luck, TomC
Title: Re: Adding belt driven alternator on an 8v71
Post by: AndyyCoulic on April 18, 2015, 04:17:57 PM
Bottomacher,
I would love to see this assembly you speak of!

Thanks for the insite clifford and tom. I will also look into the other drive gears. Bus used to have a/c so maybe i can use that one.


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Title: Transmission PTO Driven Generator? ...
Post by: HB of CJ on April 18, 2015, 05:04:52 PM
Room or space would be a concern.  Any way you can look and see if you have the space to consider mounting a transmission PTO driven generator?  I do not know if the 730 had such.  The Spicer may.  Just me.  HB of CJ (old coot)
Title: Re: Adding belt driven alternator on an 8v71
Post by: RJ on April 18, 2015, 10:36:57 PM
Andy -

If your 4106 engine is stock, there should be a PTO near the torus fan drive that was used for the A/C compressor.  Other '06 owners have used that PTO to mount both alternators and/or twin A6 GMC A/C compressors.  A little tight, but you do have that access hatch between the rear wheel and the radiator that makes it a little easier.

FWIW & HTH. . .

;)
Title: Re: Adding belt driven alternator on an 8v71
Post by: AndyyCoulic on April 19, 2015, 01:16:06 AM
I will check the next time i go out to the bus! The engine is stock, but not the original engine from the bus, and the ac has been removed. But I'm hoping its there behind a block off plate.


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Title: Re: Adding belt driven alternator on an 8v71
Post by: Bill Gerrie on April 19, 2015, 05:32:25 AM
Andy
If you are referring to the block off plate on the fan drive for the A/C and there is a plate then the drive is gone. If you have a V730 and there is a plate between the converter housing and the shift linkage I have a complete drive assembly with pulley you can have for $75 plus shipping but to install it you have to remove the transmission. The drive gear must be installed inside the transmission. The mounts are in all V730's but no gear.   
Title: Re: Adding belt driven alternator on an 8v71
Post by: AndyyCoulic on April 19, 2015, 12:11:46 PM
Dang! Its blocked off so thats a bummer. I have the 4 speed spicer, so that sadly won't work for me either.


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Title: Re: Adding belt driven alternator on an 8v71
Post by: bevans6 on April 19, 2015, 01:14:56 PM
What drive positions are free on the back of the engine?  I've seen pictures of GM's with belt drives.  If you could drive it off the blower drive position that would double the speed of the pulley and make it a lot easier.

Brian
Title: Re: Adding belt driven alternator on an 8v71
Post by: luvrbus on April 19, 2015, 01:45:01 PM
With a 4 speed manual that takes away 1 drive for the oil pump for the transmission so you are screwed on the back with the 4 accessory drives most 4106 have 
   
Title: Re: Adding belt driven alternator on an 8v71
Post by: TomC on April 20, 2015, 03:46:08 PM
Unless you already have the V730 PTO drive shaft sticking out, there won't be the drive gear inside. You'll have to pull the trans to install the PTO gear for the shaft. Good Luck, TomC
Title: Re: Adding belt driven alternator on an 8v71
Post by: luvrbus on April 20, 2015, 04:01:46 PM
The AC on a 4106 drives off the Torqus fan I have the drive, the ring gear will still be there you pay the shipping and it's yours but that is a awful place for a alternator 
Title: Re: Adding belt driven alternator on an 8v71
Post by: chessie4905 on April 20, 2015, 04:20:43 PM
   Why not change the present alternator to 24 volts and use a smaller 12 volt automotive alternator to keep the start batteries charged and 12 volt items supplied.
Title: Re: Adding belt driven alternator on an 8v71
Post by: bottomacher on April 24, 2015, 07:51:24 AM
I finally found the takeoff. I didn't realize that one ear was broken and that the adjacent one has a crack. I think it is usable with washers, but I cant say for sure.
Title: Re: Adding belt driven alternator on an 8v71
Post by: luvrbus on April 24, 2015, 08:03:29 AM
That looks like a blower driven accessory drive 
Title: Re: Adding belt driven alternator on an 8v71
Post by: bottomacher on April 24, 2015, 02:28:38 PM
I believe you're right.  I bought if for my 4106  but never opened the box until about a year after I sold it. I can't remember much about it.
Title: Re: Adding belt driven alternator on an 8v71
Post by: bottomacher on April 24, 2015, 02:46:04 PM
There are numerous additional parts but I can't get the photo small enough to post it.
Title: Re: Adding belt driven alternator on an 8v71
Post by: bottomacher on April 24, 2015, 03:18:57 PM
One more try...
Title: Re: Adding belt driven alternator on an 8v71
Post by: AndyyCoulic on April 24, 2015, 11:34:06 PM
Bottomacher
So how does this piece work?!  Does it add onto the blowers drive and add a pulley to it for something like an alternator?

Chessie4905
Was thinking about doing the swap to a 24v gear driven alternator for the house side and a smaller 12v belt driven alternator for the starter side. But still comes down to being able to connect something belt driven!

Luvrbus,
what does the ac shaft from the torus that you have look like? Don't really know what the set up used to be like.

Sorry for the noob questions! Still learning!


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Title: Re: Adding belt driven alternator on an 8v71
Post by: bottomacher on April 25, 2015, 04:07:59 AM
Yes. The pulley is shown on the left in the first photo. I expect Clifford can tell you more than I can, since I never installed it.