Re: At my wit's end, please help
 

1000 RPM will probably high enough that you get some after-run unless you shut it off in gear.

Re: At my wit's end, please help
 

Well, that 1000 rpm didn't last long. :lol: I backed it off to 950, a number I think I can live with. For whatever reason, my engine has always shut off *right now* with no after-run, even from a 1000 rpm idle. I often shut it off in gear anyway, but if I forget and put it in Park, it still shuts off quickly. That's a good tip though.....!

Re: At my wit's end, please help
 

If the motor is warm and idling with ac on it can be 600 and it should be fine. As I said before its your own judgement.:chevy:

Re: At my wit's end, please help
 

Glad it is working again.

Now you need to keep it that way. You need to increase the size of the wire from the alternator to the battery to handle the increased load that the new alternator can put out. With the stock size charge wire you are limiting the ability of the new alternator to do its job at best and at worst risking another melt down if the alternator tries to push too much juice through too small of a wire.

The stock wiring on most of the late model rigs with the high amp 12si that I have pulled apart have had 8-gauge wire and one with a longer travel path through the harness had 6-gauge. Pulling the wiring out of a new body style 88-up truck will give you the size you need with the correct ring terminal already in place on one end along with the terminal cover to match so that is where I would start unless it is easier for you to get new stranded 8-gauge wire and the right size ring terninals.

Make sure the alternator case has a good ground back to the battery as well. This will help you get the most out of what you have. I run a case ground wire back to the battery just to make sure there is a good path of travel to complete the charge circuit to take full advantage of what the alternator can do.

Re: At my wit's end, please help
 

Per HO455's advice in post #32 "The quick answer is change the battery charging wire to a 10 guage and the alternator output wire to an 8 guage if your going for the 94 plus amperage alternator". This is what I did, and I soldered a proper ring terminal on the 8ga. wire for the alternator lug. I connected a ground wire to the alternator bracket for now, and will plan on running a ground wire back to the battery just to be sure.
EDIT: Just ran a new ground wire from the ground on the fender (which is connected directly to the battery) to the alternator.... one more little detail out of the way.

Thanks for the good advice. As a couple members have said, there is a wealth of info in this thread and it should be helpful to others who might experience similar problems.

Re: At my wit's end, please help
 

I'm glad you have it up and running with a good charge.

Re: At my wit's end, please help
 

I am too, Dale.... I am too. It was an easy mod, once I got the right part & the right procedure. Had I been left on my own without help from board members, I could have screwed things up royally! ;)

Re: At my wit's end, please help
 

Good work getting the job done right! :metal:

Re: At my wit's end, please help
 

okay, I see this in my very near future.... I guess I need to round up the alternator (hope I can find it still at O'Rileys) and some proper wire.

Thank you Stocker for pointing this out on the other thread created today by 6t727t2.

Re: At my wit's end, please help
 

@Stocker - seeing you have a 72 that is likely similar to my 72 (though you are a K20) - is this what you got from O'Riley's? Just wanting to confirm the bolt up/clock stuff/wiring connections.

For the record, my C10 SBC350/TH350 is all stock under the hood (other than a modern A/C). All V Belt stuff from factory.

Also, in the wiring photos, the one were it goes to "3-wire" - seems a lot of wires are gone! Also what is/where that connector in those two photos - is that the External Voltage Regulator connector??

Re: At my wit's end, please help
 

Look at this thread. It's all explained here. Let me know if you need anything.:chevy:

http://67-72chevytrucks.com/vboard/s...d.php?t=737824

Re: At my wit's end, please help
 

I didn't mean to post in that other thread after reading it over - seems about the same information over there, as in here.

Looks like 3:00, 9:00, 12:00 - does not matter? The link for O'Riley's is still good though it seems it is easier to get a home delivery (Ultima 94 Amp Alt / Part# R111785A / Line ULT / UPC 190037039484)

DeadheadNM thank you for your example in that other thread (post #15) http://67-72chevytrucks.com/vboard/s...1&postcount=15


And I found this thread from Stocker about the part number, so that is now confirmed and also a bit after that I see O'Riley's will take my 72 Alt for the Core charge - YAY!
http://67-72chevytrucks.com/vboard/s...46&postcount=6

Also one could rewire, jumper the external regulator, or go with an American Auto Wire "External Alt to SI Converter" (PART #: 27555). I am not looking to be pulling a lot of amps but if I put in a amplifier in, I'll beef of the wires. So, I think I am going with AWW for now.

https://www.americanautowire.com/sho...conversion-kit

Re: At my wit's end, please help
 

Well, I called up Mark at M.A.D. Enterprises. That fellow can TALK - I was on the phone for a hour and perhaps 3 minutes was me ordering is full kit and passing my CC/Address to him. I am pretty sure he is a long lost brother of my dad and going on explaining things!

Unless you have a budget and want more than you'll likely need, perhaps $250 for a full kit is not for you. Personally, if I am breaking apart wiring harnesses in the engine bay and running new wire I want to do it right and once! Last thing I want to do if muck of my power in my truck!

Re: At my wit's end, please help
 

I've been following all these threads/posts about alternators.. "Which one do I need?"... "which amperage output do I look for?".. I see a lot of emphasis placed on the "clocking" of an alternator.. The "clocking" of an alternator is a totally unnecessary consideration when making your selection as the "clocking" can be easily changed.. When these alternators are assembled, all the internal components -- stator, rotor, diode bridges, voltage regulator, etc. -- are assembled into the rear case half.. The brushes are placed in the brush holder in the fully retracted position and held by a plastic rod. This rod passes over the end of the brushes and sticks out through a conveniently placed hole in the back of the case. The rotor shaft is inserted into the rear bearing.. The two case halves are slid together in what ever "clock" position is called for.. The four bolts are installed and the plastic rod is removed, allowing the brushes to make contact with the brush rings..

Buy/select an alternator of whatever amperage you desire and/or need.. Remove those 4 bolts holding the case halves together.. Gently and slightly separate the case halves about 1/8" - 3/16" leaving the stator fully seated in the rear half and the rotor (the part/shaft that has the pully on it's end) partially seated in the rear case half.. Rotate the front case half to the proper "clock position" for your application.. Reseat the case halves and replace the bolts.. If you slip up and separate the case halves too far and the brushes slip off the brush rings, just fully separate the case halves, reinsert the brushes into the brush holder.. The brushes can be held in place using the red plastic tube that comes with a chemical spray cleaner.. Position the case halves in the needed "clock position" and push the case halves back together.. Install the four bolts, remove the plastic tube, and you're good to go..