Non Mopar alternator question

[d55dave]

We are just getting my buddies race car running, he bought it with a hurt engine which has now been fixed. We have no alternator output and I am wondering if anyone can help me. The large hot lead goes to the battery and has 12 volts to it, but the two "spade" connectors have nothing going to them. I am guessing that the alternator has never worked since it was installed as I suspect the "turn on" or "energize" wire is missing. The car has dual batteries and in the past always had a charger on it between rounds.

My questions are;

1 - can anyone identify this alternator?
2 - does anyone know how to wire it correctly?

I tried putting 12 volts to the two spade terminals, one at a time with the car running. One had no effect on the output, the other one resulted in 13.8 volt output, but significant laboring of the engine at idle leading me to wonder if there is an issue, or the batteries are just low and requiring a lot of amps to charge.

Ideas / suggestions?

 

[magnumdust]

It looks like the small 40 amp denso that people put on big block cars. Came on 90s toyota pickups

 

[Lonewolf3165]

The one you applied 12v to & got 13.8v out of it should get power with the key on. With the engine running & voltage applied, check for voltage coming OUT of the other terminal. This is for the charging system light and should get connected to the circuit accordingly.

The charging system light comes on when there is NO voltage coming out of the terminal. The bulb is wired positive with Ignition on 1 side & the other is grounded. Also connecting to the ground side of the bulb is the wire coming from the alternator. When there is no voltage form the alternator the bulb is on. When the alternator starts producing voltage on that wire it takes away the ground & the bulb goes out because you cant have a circuit with 2 positive sides on the bulb(or any component).

 

[d55dave]

Thanks for the info guys. I assume then that this alternator has an internal regulator?

 

[nm9stheham]

BTW, if that is a Dayco Top Cog belt, ditch it. They can slip badly with no squeal and you'll never know they are bad.

 

[zac_F71]

Thanks for the info guys. I assume then that this alternator has an internal regulator?

Yes internally regulated - like said

1 wire gets switched 12v source
1 wire is charging sense wire (I would route this to the + side of the battery)
large wrapped wire is charge wire - should be 4ga. wire and a fuse should be choosen based on the amperage output (40amp - I would do a 45amp fuse) - it should be no more than 1ft from the battery..

I have a Mancini alternator bracket and a 120amp toyota alt on my 383 and this is how they are wired - if the car has the stock voltage regulator in it, unplug and remove it, wrap the plug in electrical tape...

FYI you can buy replacement pig tails on ebay - I got one for mine for $10 shipped