Upgrading my alternator on my 6.2 diesel.
 

I noticed the gauge was acting weird and decided to have the alternator tested. Yep it was bad. Got to looking and someone had put on a 37 amp unit off of an astro van. Not sure what they are supposed to have but I thought it was around a 66 amp unit. I didn't want to put a new 37 amp alt. back on so I upgraded and bought a 94 amp. I just felt that it would be better for charging both batteries and if I decide to upgrade the radio or put in new updated relay harnesses for the PW and headlights that it would be a better fit.

Picked the new one up a little bit ago and getting ready to put it on and see how it does. Ready to start driving this truck to see how good it's going to be. I just bought a reman from Napa since I didn't really have the time to wait to have one shippped in. We just looked through a few of them until we found one that matched up and the clock position was in the right location. This is not what it called for by application.

Re: Upgrading my alternator on my 6.2 diesel.
 

Someone in the past probably did the "oh yea that old one up on the shelf will fit fine" when they needed an alternator for the truck in one of it's past lives.

Re: Upgrading my alternator on my 6.2 diesel.
 

Oh I am sure of that. Just didn't figure it would have lasted very long trying to charge two batteries all the time.

Re: Upgrading my alternator on my 6.2 diesel.
 

rs74, the Delco 10SI and 12SI can be "re-clocked" if the wiring connector locations aren't good. Just pop the four bolts out of the back, and then rotate the two housings relative to each other and put the bolts back in. It's easy. Just make sure you don't split the housing apart or you'll have to hold the brushes in to slip the commutator back in.

All of the different ampacities are effectively in the same housing, so the 37 Amp model will do its best to charge the two batteries with its 37 Amps, but may not succeed. But, the alternator won't fry itself.

Re: Upgrading my alternator on my 6.2 diesel.
 

CS130 is a good upgrade and will bolt right in as long as you get the 12/6 positions. CS140 is also another good alternative but requires a bit more work.

Re: Upgrading my alternator on my 6.2 diesel.
 

Clocking the alternator will void the warranty - aparrently they think we're not smart enough to work with the brushes.

I thnk my fully loaded truck has a 78 amp.

Make sure you have the right pulley, big pulleys with low rpm diesels = poor charging. Belt alignment is critical. Also,the correct belts are NOT a standard size, they are a HD that has a wider cross section. Standard belts bottom on the grooves in the crank and water pump and will slip. No one has the correct belt in stock, but the 'alternate' belt is the standard width.