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Discussion Starter #1
Instead of putting the original 1600 generator back in my 67 GTV which is getting a 1750 motor, I am going to install the alternator from the 1750. solves a problem in that the mounting bracket from the 1600's gen doesn't fit the mounting boss for the 1750, plus improved charging with alt.
The Alt is externally regulated, and as it came off the car, it had a "Mixo" 3-terminal regulator. Can't find any info on the brand (non-original?), and the terminal markings are 1-3-4 instead of D+,D-, DF. The B+ terminal on the Alt is wired to the #1 terminal on the VR, but according to the wiring diagram, no wires are supposed to run from the B+ terminal to the VR. As I read the wiring diagrams for both 1600 and 1750 GTV's (thanks Papajam!), it seems a pretty straightforward process to hook up the alt, but I'd like a second opinion so I don't fry anything important.
first, do I trash the Mixo VR, and if not, what do the terminals correspond to?
as far as the hook-up, here's what I think is correct:
D- on alternator goes to D- on VR
DF on alt goes to DF on VR
D+ on alt goes to gen light
D+ on alt goes to D+ on VR
B+ on alt goes to Horn relay
B+ on alt goes to Battery+?? (wiring removed from the 1750 goes to starter, not sure why it is better to go 4 ft across engine bay instead of 6 inches to battery post?)
B+ goes to power fuses 3-4-5 ('67 wiring, corresponds to fan, turn signals, brake lights int lights, wipers, lighter, parking lights, dash lights)

as removed from the 1750, the D- (brown) wire is on the un-marked terminal with the black rectangular box attached by a jumper to the B+ terminal, and there is no marked D- terminal. is this the D- terminal?
have I missed anything?
thanks for any help,
Stan
 

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That Mixo 'regulator' looks all the world to be a horn relay.
 

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I suggest that you get a later model alternator with a built in regulator. It will be simpler to wire and it is likely to have less wear and tear than the one that you have.
 

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As Papajam notes, what you have is a horn relay, not a voltage regulator. The correct regulator for that alternator looks like:

and is priced at $53 from Centerline (see http://www.centerlinealfa.com/cgi-local/SoftCart.exe/online-store/scstore/p-VR351.html?L+scstore+rsld5294ff840f84+1299308099. )

A newer model, all electronic, aftermarket regulator is also available. These are priced at $32.50 and look like:

See: ( http://cgi.ebay.com/ebaymotors/STANDARD-MOTOR-PRODUCTS-VR-124-Voltage-Regulator-/160508485768?pt=Motors_Car_Truck_Parts_Accessories&fits=Make%3AAlfa+Romeo&hash=item255f0d2088 )

But, as others have written, installing a later model alternator with internal regulation would both simplify the wiring and ensure that you have new bearings, brushes, etc. bnrparts sells rebuilt alternators for late-model spiders for $120 with no core charge ( http://cgi.ebay.com/ebaymotors/Alfa-Romeo-Bosch-Alternator-High-Output-80-Amp-1967-80-/280555778939?pt=Motors_Car_Truck_Parts_Accessories&hash=item41526d737b ). That's a bit more than the cost of a regulator, but it would offer a lot of advantages for the money.
 

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Discussion Starter #6 (Edited)
Papajam is absolutely correct. THIS is the VR. Correct number and colors of wires and everything. Didn't have the Wiring diagram with me when I pulled it off, so I removed the most likely box. read Peter's thread, glad to know I'm not the only one.
Peter, thanks for the link (and thanks to GTD for the wiring explaination), it didn't come up in my search. It's exactly what I need, My alterations are identical to yours. As I understand it, the Dynamo light circuit for an alternator is reversed from that for a generator, and I can't just splice the blue gen-light wire into the green D+ terminal on the Alt. can anyone confirm this? if so, I think I'll dispense with the light for now, sort it out later. The car is ready to start otherwise. It's -2 and snow/ice, so it's not like I'll be going out for a drive this week.

can anyone confirm the D- terminal on my alt? Jay, you are probably right. My alt sounds pretty clunky and might have bad bushings. I'll start with it, and move to internal regulated alt when it dies. I've got one of those on my parts car. Maybe I'll just go straight to that option, now that I think about it. Any opinion on running the alt output to the starter as opposed to tthe Battery terminal? seems much simpler routing.
Stan
 

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As I understand it, the Dynamo light circuit for an alternator is reversed from that for a generator, and I can't just splice the blue gen-light wire into the green D+ terminal on the Alt.
Well, no it isn't reversed and yes you can splice the small blue and green wires.

The light works on voltage potential; the higher the potential, the brighter the bulb glows.
When the key is turned on and engine is off, battery voltage is supplied to one side of the bulb. The other side of the bulb is grounded through the charging device. The bulb is receiving maximum voltage potential (12v) and is on bright. When the engine starts and the charging system comes online, the 'ground' wire for the bulb is now supplied with charging system output voltage. Since charging system voltage and battery voltage are (theoretically) the same, there is no voltage potential at the bulb (0v) and the light goes out.
This basic operating principle holds true for both generators and alternators.
 

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Any opinion on running the alt output to the starter as opposed to tthe Battery terminal? seems much simpler routing.
Stan:

Connecting to either the starter or battery works equally well. Those clever little electrons will find their way to the right place either way.
 
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