1965 BB charging question

[Joel T.]

I'm working on a newly acquired 1965 BB car, and am working through the myriad of small "issues" which are always there.. One issue has to do with the charging system.

When we got the car, it would significantly discharge when the lights were on at idle..... needed to be 1500-2000 RPM to bring it back to zero. I figured it was a blown diode in the alternator and swapped the unit out for another one I had as a spare... same problem.

I next replaced the voltage regulator. Went to Napa and picked up one of their replacement parts. Now the car charges all the time, typically 10 amps at idle and 20+ at speed. I replaced the original battery with my yellow Optima battery (which was fully charged) and am having the same issue. I really do not want to cook that battery!

Any ideas as to what to check next? This car supposedly came with a "transistorized" voltage regulator... I do not think I have ever come across one of those.. could that be the issue?

Thanks in advance,

Joel

[Jack H.]

Re: 1965 BB charging question

Some of the early production L78 cars left the factory with the solid-state voltage regulator, but that's not your problem from the description you give. The solid state voltage regulator was a 'drop-in' replacement for the electro-mechanical '515 V-reg. Shouldn't make any difference except the transistorized version would respond a 'titch' faster to changing circuit loading situations.

What you've done (change alternator, change v-reg, change battery), is the typical repair path used by hobbists. It's frustrating and pretty inefficient.

In situations like this, I STRONGLY suggest folks go make an appointment with a local auto electric shop. Most have a nifty, wheel up, diagnostic cart for fault isolation that can control/exercise the separate components of the charging system (no guessing involved) AND do the work on-car where there's visibility of the 'nest' (interconnect wiring).

If charging components test good (takes a whooping 15-20 minutes at very reasonable cost), they can test the discharge profile of the vehicle with the engine turned off (do you have a minor short somewhere that's the cause of the problem?). If so, proceed to isolate the specific circuit involved and use their tracing tools (probe the outside of wrapped harness bundles) to detect EXACTLY where the fault is...

[Joel T.]

Re: 1965 BB charging question

Hi Jack,

Great advice as always, thanks...

This is a late '65, an L28 (one of the last 300 or so made that year). I need to find someone I trust here in NJ to do that diagnostic you outlined. I've also ordered a "correct" Voltage Regulator from John Pirkle but I think I will hold off on installing that until I have a better idea what's going on.

The other "symptom" is that the charge is not steady but rather pulsates.... I'll get deflection of the ammeter to the right which fluctuates from near zero to maybe 20 amps... Inside the car the lights will get bright and then dim. I've seen that before but the system will usually return to zero once the initial discharge from starting is replaced.

I do not see a short or a drain on the ammeter. I have a battery cut off which I use whenever the car is parked.

At this point I am thinking that the new regulator may be bad or I have an issue with the wiring itself. Sunday when I replaced the battery I got a good look at the wiring harness connections through the dash... pretty cruddy to say the least. I might just clean all that up before I do anything else.

Regards,

Joel

[Salvatore I.]

Re: 1965 BB charging question

Joel

I used Manasquan Generator in Wall, NJ....732-681-2128...speak with Fred...Old-timer; knows his stuff....can wheel up the diagnostics that Jack mentioned to the car or take the pieces out of the car and test them; either way..has ability to rebuild any component right on-site....very, very reasonable...

Sal