Alternator Swap

Alternator install

I have followed the advice of one of the threads and purchased a GM 65 amp Alt from NAPA, part number 13-4011B. The problem I see now is that the old alt had three wire connectors, and this new one only has two, see the pics attached.

Have I got the right one? If yes what is the wire configuration?

New Alt-More Amps--Possible problems

I am putting this out as a seperate thread because it might get hidden at the end of my other threads. Here is my concern:

I have upgraded the old GT alt with a 35 amp output to a GM 65 amp output.

With this increased ampage do I run a greater risk of overloading the already fragile and old wireing which might cause a fire?

Should I be installing some in-line fuses? And if so where?

Thanks

PS: so far the install/swap is going well, I am off to the wrecker today to find a new upper bracket.

Graham said:

I am putting this out as a separate thread because it might get hidden at the end of my other threads.

Click to expand...

Sorry Graham, but I am trying to have the threads MORE complete, rather than more split up, when they are related, and these are related. So I merged the threads (which I had done with the earlier ones). But thanks for using the correct forum.

As for wiring concerns, the bigger alternator only increases the number of amps it puts out when required to, NOT the draw. If the load is the same, the bigger alternator will simply do a better job at keeping up the voltage. In fact, I think if the battery voltage is kept at 14 volts by the higher output alternator rather than allowing it to be drawn down to a lower value (say 12 volts), the same "load" at the higher voltage will result in a lower amperage draw. And "amps" are what heats the wires, not voltage.

As for fuses (or circuit breakers), the standard ones are still a good idea. The most important one to add is a 40 Amp for the headlights circuits, which are otherwise "protected" (barely or not at all) by the main fusible link.

HTH