Charging Fine Except Nothing at Idle Speed

[Gerrs69rr]

Thanks Bob for the reply, as usual all your points are valid and where on my mind as well, sometimes desperation clouds your thoughts. I'm going to ditch the pulley swap for now and go back to the beginning and start from scratch. I could live with dim lights and slow turn signals at night but with A/C (aftermarket from classic air) it pulls so much it stalls below my idle at 800rpm, over 950rpm it's awesome, so I have been putting it in neutral and coasting to stop light. It's just frustrating as hell not being able to figure it out...........hence my desperation

 

[RJRENTON]

Perhaps you could consider installing a "hot idle solenoid" that would increase the hot idle RPM setting by 200 RPM or so, when the A/C compressor clutch was engaged, allowing the alternator to produce more voltage and current, and to prevent stalling, due to the A/C load. This could be wired to be energized wherever the A/C is turned on and DE-ENERGIZED when powering down to prevent dieseling or after run upon shutdown. Connected to the carb linkage to keep the throttle open slightly more. There are several aftermarket parts sources available to accomplish this task at a reasonable cost. Just thinking out loud....
BOB RENTON

 

[Gerrs69rr]

All right that's what I'm talking about, a solution that doesn't have the words "catastrophically self destruct" in them. Im going to look into this, im not the best at electrical things but feel pretty good about figuring it out. I did buy and installed the headlight wire harness from crackedback here on FBBO and install went fine. I really thought with taking headlights off harness it would help my dilemma. Another thing, I was running a yellow top Optima battery for 10 years, I temporarily replaced it with a Duralast gold with 850 ccamps 1000 cranking amps and reserve capacity of 150 (minutes I assume) could that be an issue? I don't really remembering car stalling at night with the Optima.......just talking out loud

 

[440+6]

Just to let you know, I reduced the pully size many years ago, probably 10 or so, I put allot of miles on the car each year and bring it up to 6000 rpm all the time, no failures.

I had the same question for my alternator guy and he told me it will be more than fine, apparently some professionals actually know what they are doing.

 

[Gerrs69rr]

Just to let you know, I reduced the pully size many years ago, probably 10 or so, I put allot of miles on the car each year and bring it up to 6000 rpm all the time, no failures.

I had the same question for my alternator guy and he told me it will be more than fine, apparently some professionals actually know what they are doing.

So don't keep me in suspense, did it improve low rpm alternator output?

 

[440+6]

So don't keep me in suspense, did it improve low rpm alternator output?

Of course, 14.5 volts at 750 rpm, before it was13 i think, anyway it went from dim to full bright at idle, alt speed increased by 10 percent or so if i remember correctly, thats all it needed

 

[440+6]

So doing rough calculations, crank pulley 7.5 inch, alt 2.75 inch, at 6000 rpm the alt is spinning at 16350 rpm, that's well within limit of 18000, they can spin faster but will drop voltage output, im only at 6000 for a few seconds at a time anyway.

 

[RJRENTON]

So doing rough calculations, crank pulley 7.5 inch, alt 2.75 inch, at 6000 rpm the alt is spinning at 16350 rpm, that's well within limit of 18000, they can spin faster but will drop voltage output, im only at 6000 for a few seconds at a time anyway.

Not clear where the 18,000 RPM not to exceed number came from. Its an RPM function not time related. Perhaps someone empirically tested one to destruction. I would think that at the 16,000 RPM a very precise dynamic balance is required. At that RPM, the slip ring brushes may be bouncing slightly causing the output voltage to fluctuate and drop.
BOB RENTON

 

[Gerrs69rr]

Not clear where the 18,000 RPM not to exceed number came from. Its an RPM function not time related. Perhaps someone empirically tested one to destruction. I would think that at the 16,000 RPM a very precise dynamic balance is required. At that RPM, the slip ring brushes may be bouncing slightly causing the output voltage to fluctuate and drop.
BOB RENTON

Thanks guys I appreciate the help, 40 years playing around with b bodies and I'm still learning. The way I see it, is with every problem is another opportunity to learn something else. I'm going through everything one more time then try the pulley or Bob's idea with solenoid. I'll post my results shortly, I'm driving to Carlisle from VA Beach with 8 other mopar's so I need to figure this out.