Just call me Sean

iTrader: (1)

That kind of switching is very hard on the alternator, and kills them regularly because of it. Same reason you aren't supposed to remove the battery cable to test the alternator.

Jeff1996_352_4x4

I have a question for one of you alternator guru's. Even though I am not into the audio department, I require a HO alternator for RF purposes, radio communications. My amplifier can draw up to 150 amps continous. I am putting a 250 amp alternator in my 1996 F-150 with a 5.8 motor, air conditioning, power steering, etc. I am changing the cable over to 4 ga. and 2 ga. for the ground. I will be using a 1 farad cap between the battery and equipment.
My question is that the alternator also uses an overdrive pulley and it is suggested to use a 1 inch smaller serpentine belt to reduce the chance of slipping. None of the autoparts stores can help me with this as the belt uses a part number for the vehicle and not an exact measurement size for the belt. Has anyone ever run into this using a HO alternator, and if so, would it be possible to get a part number for a 1 inch size smaller belt?
Your help is greatly appreciated.
Just an FYI, the original belt has 6 notches, not 5.

Just call me Sean

iTrader: (1)

The length is in the part number. For instance, I was using an 870K6 which is 87.0 inches and six ribs wide.

Lazarus-F150

I second the RJM replacement. I swapped the 2G alt out of my '92 4.9L after it caught on fire. The 3G alt and swap kit aren't that expensive (considering) and they have worked great for me.

5Rangers has a great 3G swap thread that got me through the process (along with Sean):

https://www.f150forum.com/f10/3g-altenator-165829/

(P.S. Thanks again guys!)

I also second the cap suggestion for the indicated reasons.

412aaron

There's a good thread on another forum which details the entire 3G swap. It covers all the different brackets used, which ones are a direct fit, etc. Gonna try and dig it up, I'll edit this post when I find it.

Jeff1996_352_4x4

Thank you for this information. This is what I did. I went to the Gates website and looked up the part number for a serpentine belt for a 1996 F150 with a 5.8 engine. Got a part number K061020. I take it that it meant 6 ribs and 102 inches in length. I then searched through the site using different years and engine sizes. I came across a 2004 F150 with a 5.4 engine, no supercharger, with AC. Part number K061015.
One half of an inch shorter is better than nothing. The closest I could find was 99 inches and this would be too short and those with superchargers are 8 ribs.
I actually did find the exact measurements for the Gates serpentine belts and both are the exact width with the K061015 being one half inch shorter than the stock K061020.
This is good information for anyone using an overdrive pulley on the alternator, no thread hijack intended.