A1 alternator, need advice

I have an 82 vw pickup with A/C. It has the stock 65 alternator still
in it. It has been giving me fits for almost a year now. It quit and
was rivived with new brushes. I have had to rev it to 3K to get it to
generate power. I think it is time to replace it. But... I also want
good power. I run a stereo system with an amp rated at about 500
watts. This is around 40 amps when running a little under 13V. That
doesnt sound so bad with a 65 amp alternator. But I can tell you that
at present, my lights dim terribly when listening to music. Voltage
drops enough to clip my radio unit. I am getting about 12.5V in warm
weather. The voltage drops far below 11V with loud music playing. Is
it possible that my alternator is actually not pushing 65 amps, and
just needs to be replaced? Should I snag one of those newer 90 amp
units and try to compress it into the engine compartment? I love
welding and am not afraid of making brakets. If that is what I should
do, what model of a VW should I get it from? (for reference at the
parts store) Oh, and is it possible to make an alternator to put out
around 15V? That would be great! Thanks guys

wrote:

> I have an 82 vw pickup with A/C. It has the stock 65 alternator still
> in it. It has been giving me fits for almost a year now. It quit and
> was rivived with new brushes. I have had to rev it to 3K to get it to
> generate power. I think it is time to replace it. But... I also want
> good power. I run a stereo system with an amp rated at about 500
> watts. This is around 40 amps when running a little under 13V. That
> doesnt sound so bad with a 65 amp alternator. But I can tell you that
> at present, my lights dim terribly when listening to music. Voltage
> drops enough to clip my radio unit. I am getting about 12.5V in warm
> weather. The voltage drops far below 11V with loud music playing. Is
> it possible that my alternator is actually not pushing 65 amps, and
> just needs to be replaced? Should I snag one of those newer 90 amp
> units and try to compress it into the engine compartment? I love
> welding and am not afraid of making brakets. If that is what I should
> do, what model of a VW should I get it from? (for reference at the
> parts store) Oh, and is it possible to make an alternator to put out
> around 15V? That would be great! Thanks guys
>

Take the alt. to a good shop and see if they can check it out for you
and have them put in a Transpo adjustable voltage regulator after
they're done fixing whatever's wrong. Also check your wiring to the
battery, chassis ground, etc. corroded battery cables can really screw
with you. also maybe run a heavier gauge wire from the alt. to the post
on the starter. Sounds like your alt. isn't pumping the juice, no way
is even a 500W (RMS) stereo actually drawing 40 amps from the alt.

Also might want to consider a capacitor for your amplifier, that will
make the bass hit harder and at the same time be kinder to the alt.

Finally your dash gauge may be inaccurate, whip out your Fluke and check
voltage at the alt. - my old GTI exhibited the exact same behavior but I
drove it for 3 years without a jump start, so it obviously never
actually dipped under 12.5V at the battery. Could be an inaccurate
gauge or also old, cruddy connections between the engine bay and the dash.

One last thing, is your idiot light working? (i.e. does it come on
before you start the engine?) having to rev to 3K to energize makes me
think you may have a "blue wire" fault, although it could also be a
dying regulator.

good luck

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

wrote:

> I have an 82 vw pickup with A/C. It has the stock 65 alternator still
> in it. It has been giving me fits for almost a year now. It quit and
> was rivived with new brushes. I have had to rev it to 3K to get it to
> generate power. I think it is time to replace it. But... I also want
> good power. I run a stereo system with an amp rated at about 500
> watts. This is around 40 amps when running a little under 13V. That
> doesnt sound so bad with a 65 amp alternator. But I can tell you that
> at present, my lights dim terribly when listening to music. Voltage
> drops enough to clip my radio unit. I am getting about 12.5V in warm
> weather. The voltage drops far below 11V with loud music playing. Is
> it possible that my alternator is actually not pushing 65 amps, and
> just needs to be replaced? Should I snag one of those newer 90 amp
> units and try to compress it into the engine compartment? I love
> welding and am not afraid of making brakets. If that is what I should
> do, what model of a VW should I get it from? (for reference at the
> parts store) Oh, and is it possible to make an alternator to put out
> around 15V? That would be great! Thanks guys
>

Take the alt. to a good shop and see if they can check it out for you
and have them put in a Transpo adjustable voltage regulator after
they're done fixing whatever's wrong. Also check your wiring to the
battery, chassis ground, etc. corroded battery cables can really screw
with you. also maybe run a heavier gauge wire from the alt. to the post
on the starter. Sounds like your alt. isn't pumping the juice, no way
is even a 500W (RMS) stereo actually drawing 40 amps from the alt.

Also might want to consider a capacitor for your amplifier, that will
make the bass hit harder and at the same time be kinder to the alt.

Finally your dash gauge may be inaccurate, whip out your Fluke and check
voltage at the alt. - my old GTI exhibited the exact same behavior but I
drove it for 3 years without a jump start, so it obviously never
actually dipped under 12.5V at the battery. Could be an inaccurate
gauge or also old, cruddy connections between the engine bay and the dash.

One last thing, is your idiot light working? (i.e. does it come on
before you start the engine?) having to rev to 3K to energize makes me
think you may have a "blue wire" fault, although it could also be a
dying regulator.

good luck

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

Hey, Im glad you mentioned the idiot light. This is wierd. It is on
when I turn the key on. I then goes out when the engine starts. It
then turns back on when I rev the hell out of it. The volt guage also
jumps more than a volt.

Hey, Im glad you mentioned the idiot light. This is wierd. It is on
when I turn the key on. I then goes out when the engine starts. It
then turns back on when I rev the hell out of it. The volt guage also
jumps more than a volt.

wait, that might not be right.. I cant remember exactly how the light
behaves. I think that it is normal. I am trying to of all the
malfunctioning dash lights Ive dealt with in my truck.

wait, that might not be right.. I cant remember exactly how the light
behaves. I think that it is normal. I am trying to of all the
malfunctioning dash lights Ive dealt with in my truck.

First thing to do is add another ground strap from the alternator to
the engine. The factory ground strap usually frays and fails. The
alternator has a hard time charging without a good ground. The
alternator is supposed to be mounted in rubber bushings so the ground
strap is rather important.

wrote:

>Hey, Im glad you mentioned the idiot light. This is wierd. It is on
>when I turn the key on. I then goes out when the engine starts. It
>then turns back on when I rev the hell out of it. The volt guage also
>jumps more than a volt.


Jim B.

First thing to do is add another ground strap from the alternator to
the engine. The factory ground strap usually frays and fails. The
alternator has a hard time charging without a good ground. The
alternator is supposed to be mounted in rubber bushings so the ground
strap is rather important.

wrote:

>Hey, Im glad you mentioned the idiot light. This is wierd. It is on
>when I turn the key on. I then goes out when the engine starts. It
>then turns back on when I rev the hell out of it. The volt guage also
>jumps more than a volt.


Jim B.

The rubber bushing went to hell, so I jamed a big nut into its place.
This isnt that good of a ground, so I will try the ground strap from
alternator to engine, and chassis. Does an old alternator still put
out 65 amps?