Generator to alternator switch

does a bosch 120 400 756 x 14v 55a 20 Have an internal regulator? Or do I keep the external one part of the system. ? Generator (1968 b18) is dying and could replace brushes but have An offer of the alternator from a b20. Thanks! First post btw

You would want to use the regulator and wiring to it. Which is separate if the car is stock. Regulator is on the inner fender behind the headlight. However, the B20 may have a replacement alternator which could have an internal regulator mounted on to the back of the alternator. So that is an easier hookup.

The internal regulator is a plastic unit on the back of the alternator. If you don't see that follow the wiring and see if three wires go to the front behind the headlight. That is a silver or gray metal box.

If you are gonna drive the car a lot. You want an alternator on there.

The 140 Bosch alternator does use an external regulator.

Not my pig, not my farm but I'd suggest looking into a GM alternator swap. The alternators are just slightly less common than fall leaves are, and barely more expensive. If you ever have a failure on a trip they'll have them in 5 different quality/price levels at the first parts store you come across. And from outputs as low as double what the old Bosch puts out to enough to light up the moon. All with simplified external wiring via an internal regulator (could do 1 wire, but you'd lose the warning light function. Two wires retains the light. 3 wires and you can reference the voltage from where it matters instead of at the alternator).

You'll need to get the regulator with the alternator. The regulator for the generator won't work. You'll also need to do some wiring. The heavy wire from the battery that goes to the regulator will have to be extended to reach the alternator. The small wire for the dash light can either be extended to reach the alternator D+ terminal or to the D+ terminal on the regulator. Connect the DF terminal on the regulator to the DF terminal on the alternator and likewise with the D+ terminal. D- from the regulator should be connected to the alternator case but I've seen them grounded to the body as well.

Here's some diagrams that may help.





The GM alternator swap is a good idea in theory but we've seen multiple failures of the brackets that are available.

I did have the pivot bolt that came with my kit break after a fairly short amount of use. I replaced it with a grade 8 bolt and haven't had a recurrence.

And somewhat unrelated to the alternator upgrade, but I did apparently find some massive voltage drop in the old wiring, with the new alternator in place the lights are all BRIGHT now. I had started to think all the yellow lights were part of the vintage charm. No, it was just lousy voltage.

Thanks

For the tips and diagrams! Cant wait for my fan to not slow down with each blink of my turn signal!,

That alternator mentioned does have a regulator in it. Glad I got that fact before I started the switch.

Can you post a pic of the back of the alternator? It would be unusual for that alternator to have an internal voltage regulator.

I upgraded my 123GT to a 55 amp Motorola SEV alternator. Stock is a 35 amp. The shop rebuilt it with a regulator mounted to the back of the alternator. I was glad they did that because the previous Paris Rhone external regulator had blown up inside the plastic cover.

Electricity is to be embraced not feared. Respect it and it will all be fine.

LiamLambert said:

I would be very, very careful with those operations, because it's damn electricity, one wrong move and you're out.

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Are we talking baseball out, or pet that **** on the rug out?
How many fingers that look like parking meters am I holding up?