Motor is a 72 2.2 that has bumped out to a 2.5. It has an internal regulator. Can i use this without and external regulator or do i need to convert. The motor is carbed and there is no cicuit board in the car at all. MSD 6AL, Soft Touch Rev Controller, MSD Tach Adapter all already installed. Not sure how much of the wiring harness that came with the motor I need to save.

as i understand if it has an internal reg then no need for external reg ...or 914 relayboard

Well that would be a relief.

Yeah, internally regulated won't need the circut board or anything. If you still want you idiot light to work, I think you can just hook it up to the DF term on the back of the alternator. But don't quote me on that.

You'll only need the relay board for circuits that need fuses and relays. On my six, I have an internally regulated alternator. I got rid of the relay board and wired up three generic bosch relays where the board used to be: 1 for the fuel pump, 1 for the heater fan, and 1 spare. Looks very tidy.

On the alternator, you should have three terminals: B+ goes to the starter or batter positive; ground goes to ground (duh), and DF (I think on mine it was labelled 61) goes to the generator dash light. The porsche tech bulletin on switching from an external to an internal regulator states some alterntators need a resistor put across the dash light to pull enough current to make the light go out.

Thanks for the replies, this is exactly the kind of info that helps.

The pic is of the alternator that I have.

It was clear from the existing wiring harness that came with the motor what goes where, and will be eliciting some local help to get that wired correctly into the car. Not very good with electical and know someone that is really great with this stuff so maybe he can lend me a hand.

How about the ground strap? Where does that go from and to?

The fuel pump is on a seperate switch currently so that is all set, and this is not a street car so no heater fan.

Are you sure that's an internally regulated unit? Doesn't resemble the Valeo or Paris-Rhone to me, but the angle's funny.

As far as where to ground, any good grounding point on the chassis should be fine.

Alt looks like a early stock Bosch with no internal regulator.

QUOTE (914Sixer @ Jan 18 2006, 06:40 AM)

Alt looks like a early stock Bosch with no internal regulator.

Here is a photo of a non-regulated alt.

Well looks like I have to go external. Can i use the stock bosch regulator from my 73 2.0?

QUOTE (1973914 @ Jan 18 2006, 06:09 PM)

Well looks like I have to go external. Can i use the stock bosch regulator from my 73 2.0?

In a simple answer.... YES!

Is the more complex answer - Yes, but you will destroy the alternator nd the rest of your electrical system in the process?

Nah, you should be fine. This diagram should help: 914 alternator / VR hookup

You have two choices. If you have your original relay board with the regulator attached you simply plug the triple connector from the alternator to the board. Or if you are not using the board you attach the female connector from the alternator directly to the regulator. However, if you do so you must reverse the red and green wires (brown ground stays in the middle).

Thanks guys - appreciate you sticking through this with me. One last question" You say to ground to the chasis, but the copper strap that was attached is not overly long. What is the preffered method and location from the alternator and to the body?

I have a brown insulated wire, not a strap. Regardless, it attaches to one of the studs on the alternator body to which the plastic housing is attached. The other end goes under a nut on one of the studs at the top of the case just behind the alternator.
Then you have the large red to the starter solenoid. The red, green and brown go to the regulator. Also, a wire goes from the regulator to the "gen" light on the dash (shown as blue wire to K in the diagram linked above).

QUOTE (Porsche Rescue @ Jan 19 2006, 12:10 AM)

You have two choices. If you have your original relay board with the regulator attached you simply plug the triple connector from the alternator to the board. Or if you are not using the board you attach the female connector from the alternator directly to the regulator. However, if you do so you must reverse the red and green wires (brown ground stays in the middle).

Soooo.... How does that hook up the generator light in the insturment cluster?

The alternator won't charge if the light is not in the circuit (the light provides the exciter voltage to start the alternator charging), and the relay board connects the charge light to the Voltage regulator.

That happens through the relay board if it is used. If no board, I think you have to connect it to the regulator terminal along with the red wire from the alternator (see diagram). However, I used my board so have no experience. But it is true that the light must be in the circuit.