sbc alt issues

[jkl72-40]

Howdy,
71 fj55 sbc w/chevy alt,
lights are very dim and battery is not charging I think this is an alternator issue but seeing how this is my 1st toylet (toyota chevolet) I just want to make sure before I spend $88 dollars for a new alt. I have been driving it for 4 months and the motor was used before I put it in.. your .02 is appreciated
thanks
are there way of checking the alt while its running?

 

[Rice]

With engine running disconnect the battery. Alternator output should be enough to keep engine running. Note that this is not fool-proof. Best to let Autozone test the charging system since it's free.

To rule out the battery try giving it a full charge on a charger and then leaving it unhooked overnight to see if it will hold the charge.

 

[pjohnson]

Voltmeter
The 'how' kinda depends on the alt type.
You can have the alt tested at most auto parts stores. If it's not an internal regulator type alt, there will be a regulator that could be going bad.

Phil

 

[jkl72-40]

Its a 10si is that internal reg or not?

 

[jkl72-40]

I'm not using the toyota regulator so I would think the 10si has an internal regulator

 

[pb4ugo]

Use a voltmeter or go to the autoparts store to test. You can have mixed results w/disconnecting the bat while it is running.

 

[lone gunman]

the 10si is internally regulated. check out Alternator Parts,High Output Alternators,Chrome Alternators,Quick Start Rebuild Kits

 

[jkl72-40]

Cool Thanks!!