We actually drove this 65 valiant 170 down the road yesterday. It was having stumbling issues. A mechanic came and adjusted the points and reinstalled the distributor. Then advanced the timing. It did pretty good down the road we only raised it up to 45-50 mph because it was a neighborhood. But he said the alternator was charging but not enough. Is that a bad alternator or regulator? How do I know?
Alternator discharging, bad alternator?
- Thread starter wh23g3g
- Start date
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TrailBeast
AKA Mopars4us on Youtube
Probably either the regulator or bad grounds, as usually alternators charge or don't.
Make sure the regulator is well grounded (clean the mount points)
You can also pull the alternator and places like Autozone will check it for you.
Make sure the regulator is well grounded (clean the mount points)
You can also pull the alternator and places like Autozone will check it for you.
nm9stheham
Well-Known Member
Or, use a voltmeter and test the battery voltage when the car is warmed up, is at FAST idle, and with the battery well charged overnight. The battery should then read 13.7 to 14.3 volts.
That vintage of original alternator is likely a 35 amp one, and will not put out a lot of charge. Look up 'roundback' versus 'squareback' alternator here to see which you have, or post a pix of the back of the alternator.
That vintage of original alternator is likely a 35 amp one, and will not put out a lot of charge. Look up 'roundback' versus 'squareback' alternator here to see which you have, or post a pix of the back of the alternator.
BillGrissom
Well-Known Member
Have the mechanic flesh out "not enough". If it keeps the battery charged, it is working fine. To see what the max output is, remove the field terminal (only one on yours) and jumper 12 V straight from BATT+. That should make the alternator put out max current (which varies w/ rpm). Watch your dash ammeter as you rev the engine, or even better install an in-line ammeter. I have a DC clamp on meter for that. Also, verify that the other brush has no voltage drop to the case).
Also, check that the case of the alternator is very close to BATT- voltage. I once swapped one in an auto parts parking lot and the new one still didn't show charge. I then ran jumper cables from the alternator case to BATT- and it charged. I put the old one back (w/ frame attachments sanded) and it then worked fine, so got a quick refund. Aluminum is bad for corrosion and that was in Atlanta. People here in CA have no idea what easterners deal with.
Also, check that the case of the alternator is very close to BATT- voltage. I once swapped one in an auto parts parking lot and the new one still didn't show charge. I then ran jumper cables from the alternator case to BATT- and it charged. I put the old one back (w/ frame attachments sanded) and it then worked fine, so got a quick refund. Aluminum is bad for corrosion and that was in Atlanta. People here in CA have no idea what easterners deal with.
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