BillJack

I own a '64 Ninety Eight and am planning on replacing the alternator. On the Advance Auto website, there are 55 amp, 61 amp, and 100 amp alternators. Does anyone know what amperage is the stock alternator for my car? What advantage would the 100 amp alternator provide?
Thanks for your help.

quaddriver

A bigger flash of light when it shorts out? ;-)

There is really no way of surely knowing unless you had your original build sheet, although at times you can make a guess based on installed equipment...AC and power things usually get at least 1 step up.

generally I tell people, if it bolts, it fits, but that assumes not a large difference in case size or clocking, and if memory serves, that would have an external regulator with contactor points in it...was there an updated size on that as well should you go larger? that is where I'd look first

MDchanic

I can't speak for '64 specifically, but if you have the original alternator, typically, the output is stamped into the edge of the case, along with the part number.

Are you replacing the alternator because it doesn't work, or because you want more current?

If it doesn't work, you can buy all of the internal parts to rebuild it very cheaply at NAPA or RockAuto.

- Eric

BillJack

Thanks! I found 42 amps stamped on the housing. I'll probably purchase the 61 amp alternator to carry the extra load from a transmission cooler fan I added.

MDchanic

Definitely count the current draw of everything that you might have added to the car, including stereo equipment, when deciding what size alternator to install. The originals tend to have very little extra capacity for their applications.

I am not an expert on regulators, but I do know that, especially in the earlier years, there were a few different regulators for different alternator outputs, so, if you're going larger, check your regulator number and be sure it can handle the larger alternator, get a new regulator as well.

- Eric

BillJack

Thank you for your help. I checked the alternator housing and you are correct. The amperage of "42A" is stamped on the housing. Also thanks for the rebuild tip. I'm anxious to get the car running and since the price of a remanufactured alternator isn't very much, I'll buy the new one and possibly rebuild the original at a later date.
What's happening: I've noticed that the voltage off my new battery normally reads in the 13.8 to 14.2 volt range. However yesterday the car was running poorly once again. So I checked the voltage and it was only 12.6 or thereabout. I've had this problem before, and thought I corrected it after tightening the alternator belt and cleaning the electrical connections, so I was surprised to see this happen again. BTW, I changed the voltage regulator and ignition coil when I first purchased the car about two years ago. I'll have the alternator checked out at Advance Auto before I purchase a new one. I plan to go there after work today.

MDchanic

Definitely hang onto the old one.

Here's RockAuto's listing of alternator parts for your car:

http://www.rockauto.com/en/catalog/o...576,electrical

- Eric

BillJack

OK, I'll get a larger regulator also. Thanks again!