Alternator help

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kielbasavw

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I have a 65 valiant slant 6. Charging system was upgraded to a square back alternator with electronic regulator before I owned it.
Lately I've been having some odd electrical problems. Radio shuts on and off when headlights turn signal are on durING idle and sometimes at highway speed. Checked with multi meter. Idle I get 12.25v at the alternator. When I Rev the pissue out of it, it barely reaches 13v.
I have a spare alternator that was in a bunch of slant 6 parts I picked up. This is a round back with 2 FLD prongs that have continuity to each other but not the through the housing.
How would I set this up if it will work? A buddy of mine says he's never seen one like this. Could I just hook the 1 FLD wire to one prong and the 2 thicker wires to the large stud? I have no idea if this alternator works to begin with but might as well test it out
 
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It will help if you show a picture of the regulator, it should be an electronic version of the early regulator.

The regulator has three connections, ground, IGN, and FLD. The IGN connects to a blue wire that hot when ignition is on. It is on the supply side of ballast resistor, not coil side. The FLD is connected to the green wire that goes to field connection on alternator.

Since you have a voltmeter, check the voltage at the IGN terminal, it should be close to battery voltage when running, typically 13.8 to 14.4V. If that connection is poor, the regulator will be unable to supply enough field current for regulation.
 
My regulator has 2 connections. I popped off the cover and found circuit board inside. Rubberband is there to hold in plce as silicone dries (that's how it was attached in the first place.)

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Just checked voltage at the ignition prong of regulator. While car is idling. Directly to battery leads I'm reading 12.40v. While grounded to battery and then on ignition prong of regulator, 11.10v
 
The voltage measurements indicate a drop of 1.3V from battery thru bulkhead, ignition switch, and back thru bukhead. That is too much, only a few tenths is acceptable. Also check voltage from regulator the case where it bolts to body to battery negative. It should be close to zero volts.

Typically what happens is the alternator will put out 13.8V plus the 1.3V, or about 15.1V, too high of voltage. Since that is not happening, other problems exist too.

If the green wire is detached from regulator, and connected connected to battery plus, while monitoring battery voltage, the alternator can be checked. The engine speed can be increased, but do not let the battery voltage exceed 14.V. There is a significant shock hazzard, so be careful when you make and break field connection to battery. If voltage is a maximum of 13V, in first post, the alternator or other connections could be at fault.
 
Negative of battery to housing of regulator was .01 - .02v. Took off field wire and jumped to battery positive. At idle it was reading 12.65ish and when reved, I was able to get it to 15v and it would still climb.
 
The alternator is good if it puts out 15 volts when the field is connected to battery power. Replace the regulator and fix that voltage drop.
 
Skykeith is correct. Doing both should fix the charging issue, and improve your ignition quality. Check voltage again to verify after changes. The battery if newer, may recovery from the low charge level.

There are also a couple primary wires that appear to be close to the ignition coil secondary tower, best to move those, so they are 1/2" or more away. High voltage there could inject transients, that may have contributed to regulator failure. Transients over time alter resistor values used to control regulated voltage. I learned that doing spark discharge tests.
 
Battery is brand new. Couple month's old.
This seems to be working backwards than I would think.. I'm not big into electrical.I thought by bypassing the regulator, and alternator capable of 15v the regulator would be at fault? But I guess not.
So if alternator is bad. Is it possible to hook up and test the round back alternator mentioned in my first post? Thanks
 
Bypassing the regulator, applied full field to alternator, and it seems to work. The voltage test revealing 1.3 V drop suggests problem of voltage drops that need to be fixed. The regulator also needs to be replaced. Have you read post #10 and #11. Ignore post #9, no proof on that by photo observation.
 
Ahh I knew I wasn't crazy. Totally missed sky Keith's post. I thought his was the link "battery and alternator is bad"
So I will replace the regulator.. and I should be done..? Thanks!
 
kielbasavw said:
Ahh I knew I wasn't crazy. Totally missed sky Keith's post. I thought his was the link "battery and alternator is bad"
So I will replace the regulator.. and I should be done..? Thanks!
Click to expand...
No fix the voltage drop issue too, or the overcharging will boil battery. Also get the wires away from the coil to cap cable, or your new regulator may die early, read post #12.
 
I thought the voltage drop would be fixed through regulator. How would I find the voltage drop? Other things I never mentioned that maybe relevant. I converted to mopar electronic ignition, and soon to be switching to hei. And new standard US Ignition switch.
 
kielbasavw said:
I thought the voltage drop would be fixed through regulator. How would I find the voltage drop? Other things I never mentioned that maybe relevant. I converted to mopar electronic ignition, and soon to be switching to hei. And new standard US Ignition switch.
Click to expand...
Read top of post #7, if the ignition switch is good, then bulkhead connections are likey problem. You can measure the drop with a single measurement, battery plus to IGN terminal on regulator, engine running.
 
Lucky you have a 1965. That year and 1963 were the only ones w/ thick buss-bar feed-thrus for the thick ALT and BAT wires in the bulkhead. If they look green on the engine side, unscrew, sand slightly, and connect tight w/ silicone grease. The dash ammeter is often a drop, due to loose or green connectors. There is also a "fused junction" that distributes the ALT feed that often turns green, but unlikely if the car lived in the OC. It is wrapped in vinyl tape in the dash harness. Anyway, you can search for all such voltage drops w/ a multimeter before digging deep. Could be in the key switch, or its connector. As a quick test, clamp a jumper cable from the ALT big stud to BATT+, which will bypass the route thru the cabin.

Other voltage drops people miss is from the alternator case to bracket and engine block. That stopped the alt in my 69 Dart from charging. Also, insure no drop from engine block to BATT-, and from body to BATT-. Note that new cars use many more dedicated ground connections. I guess the designers learned. I am surprised you measured a good connection from the Vreg case to BATT-, given your rusty sheet-metal screws which that relies on.

Re alternators, most people ask the other way about field connections. Most round-backs had one brush (field wire) bolted to the case. All square-backs had two isolated brushes (field terminals). Someone correctly grounded one field in your square-back. You simply need to do the same in your round-back, using a wire. Doesn't matter which terminal. Apparently, you got a rebuilt alternator which was setup for the later style Vreg (isolated field), and they expect people using it on older cars know to ground one terminal. I doubt the 2 thick wires on your alternator's big stud were factory. Where do they go? Factory would be straight to the bulkhead connector's ALT bus-bar. Anyway, hook both the same way to the new alternator. Perhaps one is a bypass of the cabin route (test jumper above), which is termed "The MAD Bypass".
 
Just installed the new regulator. At first it didn't help. The battery was reating weak on the tester I let it charge all day yesterday. Now I drove to the shop with no issues.
Volt meter reads 12.90 - 13v on the alternator at idle. And when I Rev it, it seems to stop at around 15.40v

I tried cleaning bulk head connectors under engine bay. And checked with BATT- and red prong on ignition side of regulator. I am still reading 11.30v while battery reads 12.90 - 13v.
I even put a jumper from alternator stud to batt+ and still got the 11.30 reading.
Any ideas?
 
Sounds like poor connections getting to IGN of regulator. Cleaning will not fix connectors that are loose due to wear and heat cycles. Squeezing on the female terminals may not last, most are brittle due to age. Replacement with Packard/Delphi 56 terminals using correct crimper may work.
 
I jumped the battery to alternator with a small gauge wire. Not sure if it was too small to Make a difference on the ignition prong of regulator?

Is there specific set of wires that affect this voltage drop?
 
More problems. Car is starting to do it all over again. I'm now getting 13.2v from alternator when reving the piss out of it.
 
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