Charging Issues

[Mark K.]

I believe I have some charging issues. I have an unrestored 67 435 car. Recently my battery meter on the dash has been reading on the negative side with the battery discharging. At first I thought it was the alternator because output have been less than 12 volts. I pulled the alternator to have it tested. Apparently the alternator is fine. I think therefore that it might be the voltage regulator and have some questions:

• Can I be sure it is the voltage regulator?
• The service manual suggests that the voltage regulator can be adjusted. Has anybody tried this? Which way does one turn the adjustment screw to raise the voltage? Are there any dangers to this adjustment?
• Who rebuilds these things?
• Any other potential causes to inadequate charging?
• Thoughts?

[Gerard F.]

Re: Charging Issues

Mark,

I've done the voltage adjustment on my 67 S/B with the standard voltage regulator, pretty easy. I forget which way to turn the screw per the service manual but one of these helps:



A Walmart special, $15 to $20.

Just follow the instructions in the service manual. If you can't get it above 13.5 V at 1500 rpm and hot, you have an alternator problem. I like to keep mine between 14V and 14.5 V max with a gel battery. Over 15 V you are going to cook both a gel as well as a lead acid battery.

Just follow the instructions in the service manual.

[Jack H.]

Re: Charging Issues

You can attempt to diagnose by pulling parts one at a time and taking them to your local auto parts store, but there's a drawback to that approach: you're not testing the 'nest'...interconnect wiring of the car itself...

Plus, sometimes wiring issues can be intermittent and you'll 'fool' yourself by disturbing connection(s) in your R&R process.

My take, based on the limited info you supplied, is the voltage regulator isn't sensing the need to turn the alternator on OR it its commands aren't reaching the alternator...

Not to rain on your self-diagnostic parade, but a competent local auto electric shop should be able to roll out their diagnostic cart on wheels, connect to your car and find the source of the problem in less than 30 minutes! Getting the problem(s) fixed will probably take longer...

But, in my mind that approach is more effective than simply 'shot gunning' the system by key component substitution!

[Duke W.]

Re: Charging Issues

You can buy an inexpensive generic OE replacement regulator, install it and see if it solves the problem. If it does then you have lots of time to rebuild the OE regulator, and it never hurts to have a spare regulator as part of your "road spares".

There should be a section on regulator bench checks/overhaul in the COM.

Duke

[Mark K.]

Re: Charging Issues

Not to rain on your self-diagnostic parade, but a competent local auto electric shop should be able to roll out their diagnostic cart on wheels, connect to your car and find the source of the problem in less than 30 minutes! Getting the problem(s) fixed will probably take longer...

Jack,

What fun is that? I'd rather it take 10 hours of me struggling to figure it out than the 30 minutes where at the end of the day I still don't understand what what was happening. It is a hobby after all.

For what it's worth, the problem was wth the regulator, but instead of a rebuild, it was a simple adjustment. Certainly perplexing at first, but it helps to have the service manual to help.

Mark

[Gerard F.]

Re: Charging Issues

Mark,

You've got the spirit. It is a hobby

Have fun,