Alternator Pulley

[Jim Gearhart <jgearhart@domain.elided>]

Dan says:

> I noticed that after crawling through the woods at 5-20 MPH i 4 hi,
>when I shut down the engine and start it up I get a LARGE recharge
>read
>on the ammeter. I'm thinking this is because of the low RPM of the alt
>not putting enough charge out. BUT, I was only using the engine and the
>radio so the AMP draw should be minimal so that is making me think that
>the stock belt pulley is grossly over sized and at low crawl idle (thats
>Hofs crawl speed not Theberts) the RPM at the alt is not enough to
>actually put out a substantial charge. John L. does this sound
>resonable? Therefore, even if we were to cut the size of our alt pulley
>in half at our top redline I don't think we would be hurting the alt.
>So, I'm going to look for a smaller pulley for my alt. 
>   Here is another question, I have a two belt alt. when I add my AC air
>compressor, does the alt stay a two belt pulley?

I just went through this pulley swap project this weekend so I thought I
would share it with you.  I went to an alternator rebuild shop on Sat. with
the old pulley from my Scout alt. and asked the rebuild guy for a smaller
diameter one for my Delco 10SI alt.  He went in the back and came out
with a perfect replacement. The outside diameter of the pulley was
2-5/8" verses 3-1/2" for my stock one.  It was a  heavy duty solid
machined double pulley that the guy said came off of a Chev. Blazer alt.  
I asked him what he wanted for it and he said nothing!  He said he had a
bunch of them and even offered to paint it for me!  I gave him $5 anyway
just because he was a good guy.  

I haven't installed it yet because I need to get a different 15/16" socket to
tighten the axle nut for the pulley.  Seems the original pulley nut was
easier to get to because the stamped pulley was flared and you could
get a wrench on the nut.  With this machined pulley there is a "hole" that
the nut sits in and the outside diameter of my socket is too big to fit in this
hole to tighten the nut.  I noticed that 3/8" drive sockets are a smaller
diameter than the same size 1/2" drive ones so tonight I'm going to buy a
3/8" drive 15/16" socket and see if that fits in the hole.

On my Scout the A/C compressor belt runs off of the water pump. 
The only belts that turn the water pump are the two alt. belts.  IMHO
running an A/C compressor appears to be the only reason Scouts use
two alt. belts with the alternator serving as the belt tensioner for the
water pump.  Just a personal theory anyway.

HTH,  Jim