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Alternator selection Q
https://slantsix.org/forum/viewtopic.php?t=47938		 Page 1 of 1
Author:  Josh P [ Fri Feb 17, 2012 10:27 pm ]
Post subject:  Alternator selection Q
Looking for a solid alternator for my '66 Dart. I know there are tons of threads on this topic, but very few useful stickys and the info is so scattered and varied it is difficult to figure out exactly what I need.

So, I want better charging at idle. I'd also like to modify as little as possible (especially things that can't be swapped back). So what alternators will fit in my Dart (the stock alt seems cramped enough as it is, not sure how much larger I could go, unless I start using a slightly shorter belt), give good charging at idle, and require the least amount of modifications? Looking for a part number or what vehicles I can pull it off of.

I understand most (all?) alternators will require some bracket foolery, can I simply swap brackets (assuming I'm pulling off of a SL6)?

Also, Ammeter bypass. From the reading I've done the diode method seams easy yet effective, is this a good option? And will any other mods need to be made to the wiring (other than possibly grounding one of the field terminals)?
Author:  SlantSixDan [ Fri Feb 17, 2012 11:27 pm ]
Post subject: 
Don't do the charging circuit upgrade halfassedly. Especially not on a '66. Big post with most of the info you need is here. Any of the alternator suggestions made in that thread will work fine in a '66 with a Standard VR-128 or Echlin VR-1001 regulator by grounding one of the alternator's field terminals.

Bracket mods to fit the '88+ alternators are pretty much "cut and try"; you have to shorten the lower bracket's support tube to fit between the narrower-spaced legs of the later alternator while maintaining proper belt alignment. One of those universal curved slider brackets (this kind) can be used, often after shortening its straight end, to account for the different clocking of the top fixing point on the '88+ alternators versus the earlier variety.
Author:  Josh P [ Sat Feb 18, 2012 12:34 pm ]
Post subject: 
Thanks for the link and info Dan, good stuff. So I'll have to use two 10ga form B+? I can't use a single larger cable like 6ga? I guess I'll have to actually see the alternator before I understand how there isn't room for a larger cable...

And will I need to top bracket? I'm trying to go for a more-or-less stock look. Also how can I ID a 40/90A vs a 50/120A?
Author:  SlantSixDan [ Sat Feb 18, 2012 2:08 pm ]
Post subject: 
Unless the factory label is present, you can't visually ID a 40/90 vs. a 50/120. Either will be much more than plenty.

You probably will need to mod or replace the top bracket, yes.
Author:  Josh P [ Sun Feb 19, 2012 11:43 am ]
Post subject: 
So this morning I snagged a Denso alternator but it has dual v-belt pulley. Is this pulley going to line up? Any suggestions on getting the right pulley?
Author:  SlantSixDan [ Sun Feb 19, 2012 12:14 pm ]
Post subject: 
That's the correct pulley. You'll be using only one of its grooves -- probably the one closest to the alternator body.
Author:  Josh P [ Sun Feb 19, 2012 1:06 pm ]
Post subject: 
Quote:
That's the correct pulley. You'll be using only one of its grooves -- probably the one closest to the alternator body.
Awesome thanks Dan! So is there a single groove pulley that I could swap on?
Author:  SlantSixDan [ Sun Feb 19, 2012 2:09 pm ]
Post subject: 
Probably. Take the alternator to your nearest reputable rotating-electrics rebuild house and see if they can come up with a satisfactory single pulley for you.
Author:  Josh P [ Sun Feb 19, 2012 8:34 pm ]
Post subject: 
Ok that was obvious :oops:

Hoping not to exceed my stupid question limit, but want to make sure I don't do something dumb... why is two 10AWG recommended instead of a single 4AWG? The alt. cable that was on the car looked pretty large 4 or maybe 2 AWG...
Author:  SlantSixDan [ Sun Feb 19, 2012 8:44 pm ]
Post subject: 
A single #4 cable will be very unwieldy to attach to the alternator's output stud, and will be more difficult than two #10 cables to protect with an appropriate fuselink.
Author:  Josh P [ Tue Feb 21, 2012 6:46 pm ]
Post subject: 
After a "successful" test drive I let the car sit for a while then went to start it and got nothing. No dome light, no cranking, nothing. So I bolted my ammeter wires together and no I have dome light, but still no cranking...

So I must have done something wrong so here is how I wired it up...

Two 10AWG stranded wire from alt. B+ to positive terminal on starter (since it is easier than splicing into my battery cable or similar), with 14ga fusible links on each.

One 14AWG stranded from alt. field to ground on alt.

One 14AWG stranded from other alt. field to sense wire on my VR-1001.

One 14AWG stranded form alt. ground to base of VR, didn't end up running it back to the battery could that be the issue?

Best I can tell the ammeter is toast, and probably the fusible link. Any suggestions? During the test drive I didn't have any charge readings on the ammeter (as expected), but quite a bit of discharge readings. After dinner I'll take the multimeter outside and start poking around, but a pointer would be great. If I did indeed blow my fusible link then what needs to be fixed before I install a new fusible link?
Author:  SlantSixDan [ Tue Feb 21, 2012 7:46 pm ]
Post subject: 
Quote:
After a "successful" test drive I let the car sit for a while then went to start it and got nothing. No dome light, no cranking, nothing. So I bolted my ammeter wires together and no I have dome light, but still no cranking...
What else do you have/not have?

Do you have headlamps and taillamps? Brake lights? If you turn the key to the counterclockwise (accessory) position, can you play the radio and use the turn signals?
Quote:
Two 10AWG stranded wire from alt. B+ to positive terminal on starter (since it is easier than splicing into my battery cable or similar), with 14ga fusible links on each.
Those fuselinks are oversized, won't protect the circuit adequately.
Quote:
One 14AWG stranded from alt. field to ground on alt.
Fine...

Quote:
One 14AWG stranded from other alt. field to sense wire on my VR-1001.
"Sense wire"? Presumably to the field terminal on the voltage regulator.
Quote:
One 14AWG stranded form alt. ground to base of VR, didn't end up running it back to the battery could that be the issue?
No, but it's a good idea to complete the ground loop.
Quote:
Best I can tell the ammeter is toast
Thought you took the ammeter out of the circuit.
Quote:
and probably the fusible link
If the fuselink were dead, you wouldn't have dome light.
Quote:
During the test drive I didn't have any charge readings on the ammeter (as expected), but quite a bit of discharge readings.
That's normal when you bypass the ammeter with a charge line.

Check all the wires that connect to the starter relay and the bulkhead connector, but also don't exempt your ignition switch from suspicion.
Author:  Josh P [ Tue Feb 21, 2012 9:05 pm ]
Post subject: 
Looks like it was just my ammeter. The rest of my issue was user error combined with a slightly misadjusted shift lever. Guess the neutral safety switch got the best of me.

What size fusible link do you suggest? I thought the general rule was 4 gauges smaller.
Author:  SlantSixDan [ Tue Feb 21, 2012 10:45 pm ]
Post subject: 
Yes, 4 gauges smaller is a general rule, but not an absolute one. Take a look at the tables and charts on this page. If/when you rework this, put in a different kind of circuit protection, something quick and easy to service rather than a pain-in-the-nuts fuselink wire.
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