I’m fairly sure the alternator in this car is weak and dying. So I wanted to swap it. I looked at what was on a 13b engine and it didn’t look right but the 12a one did. But it doesn’t fit. What dang alternator do I have?? The only marking I see is BT14CE. Help please.

 

That bottom one is not any variation of first gen alternator.

 

The top one looks like it's probably an S1/2 alternator given the external fan. The bottom one looks like a GM 1-wire of some variety.

 

I know your 1980 has been modified, but make sure you know if yours requires one with or without the external regulator. The 1979 and 1980 came factory with an external regulator.

 

Slight correction on that, only 1979 had an external regulator. 1980 moved to an internally regulated alternator along with the handful of other electrical system updates.

 

Thank you. Yeah, I found a google photo match. It’s off a Chevy small block 🤦‍♂️. You have to love my dads ability to make anything work.

I assume the external regulator is that thing he screwed into the outside of the housing?

Turns out the alternator is working or so it seems. I get 14.5v out of the battery connection but I didn’t check the amps. I saw the 12a alt was 55 amps and the 13b one was 60 amps.

What I’m thinking it is, is the 16 gauge wire coming off the alternator to the entire car into a rats nest. I added dedicated alternator wire from that connection to the positive terminal of the battery.

car starts so much better and I drove it over 100 miles and battery is still charged. (By the way, gas mileage sucks! Less than 10 mpg).

I do notice the voltage gauge flickers with the turn signals. So maybe a little weak of an alternator?

again, thank you for the assistance!

 

GM 1-wire alternators are a pretty common swap on to just about anything. The fact that they're simple and available everywhere makes them appealing to a lot of folks.

That little metal can with one wire isn't a regulator, that's a capacitor/condenser, also called a radio capacitor/condenser, or an ignition capacitor/condenser. Goes by a few names depending on who wrote the book. I admittedly haven't seen one hooked up like that before, but they're common in most automotive electrical systems in some way or another to reduce electrical noise that can be heard through the speakers (generally said noise is from the ignition or charging system). The voltage regulator on the 1979 cars is a separate box located on the fender that the alternator hooked up to with a four or six pin plug if I recall correctly. Most modern alternators (including both of your units) have internal regulators.

16 gauge wire seems a bit small but depending on what electrical loads there are I suppose it could be enough. I'm not sure what the factory charging wire is but it's probably in the 16-10 gauge range. Adding a wire certainly sounds like it helped, although beware of adding multiple paths to the same location within an electrical system. If anything I might suggest disconnecting the factory charge wire if you've now run a separate, larger gauge wire to the battery.

If the voltage gauge is flicking at idle a bit I wouldn't worry about it. Even with a 100A alternator my headlights pull the voltage down some at idle because it just isn't spinning fast enough. Turn signals and other accessories do the same thing but to a less noticeable extent. With the stock 55A or whatever that Chevy one is I wouldn't be surprised if it suffered the same outcome.