Firstly, I'm hopeless with elecktrickery.

Now we have that out of the way, I'm looking to fit an R31 alternator to my 1600. I've googled, and found many good "how-to's". Problem is, most of these refer to bridging a couple of wires near the regulator. I don't seem to have a regulator ?? Whereabouts would these be mounted normally ?

My 1600 has seen duty as a rally car in the past, it is possible the wiring has already been modified or the regulator removed. I do have a few extra wires running from the alternator to the +ve terminal on the starter that definitely aren't factory original.

Anyway, what can I check ? The pic below shows what I have.

Two black wires (one thick-ish and one thinner). These seem to go to earth - if I connect a multimeter from +ve terminal on battery to these two wires, I get 13-ish volts flowing.

One thick white wire with red trace. This seems to run into the wiring harness and end up on the +ve terminal on starter motor.

Yellow wire. No idea where it goes.

White / black trace wire. No idea on this one either.

Connecting either of the last two to a 12V supply doesn't get the charge light in the dash to turn on.

The two green wires in the pic are the ones that run from alternator to + starter terminal (non-original)

The new alternator has two terminals marked "L" and "S", which I believe should connect to a 12V supply and to the charge light.

So, any tips before I load it onto the trailer and hit up an auto electrician ?

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

If the old alternator was not internally regulated, the VR is usually mounted on the drivers side strut tower at the top facing forward.
My 1971 had a Solid State VR mounted there.
The wire functions are shown here: - The complete wiring diagram is here: -
http://www.mediafire.com/download/qh74a ... age_35.jpg

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

Hey Dave,

The alternator from the R31 will be internally regulated, Therefore, if you had a voltage regulator for the old Lucas electrics on the 1600, i'd be removing it anyway.

Generally speaking:
L is for the charge light. S is the sense line that connects to the battery or +12v. That will ensure that it's not overcharging.

Thick white with red trace will go to power to the battery. Should be +12v?

Black Should be earth.

The rest, i'll need to consult a wiring diagram for you which I don't have handy atm.

Graeme will have something for sure. Once i locate my one i'll let you know. Can you tell me the year and model the alternator comes from?

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18

Just to clarify, have you saying two sets of wires? The new alternator would generally have 4: L (charge light), S (sense), Black (earth) and White (charge)

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18

New alternator seems to only have three wires - "L", "S", and the big +ve terminal. Can't see anywhere to hook up an earth to it. It is internally regulated.

Don't know what previous alternators were, I've gone through 3 or 4 over the last few years from them physically breaking stuff like mounting lugs and just kept chucking spare ones in. I've run out of spares, so I'm hoping to be able to convert to a cheaper, easier to obtain alternator. Being track only, a working alternator isn't overly important, it may have been running off the battery for a while, last few events the battery has been too flat to crank it over by the end of the day.

I can't see anything in the engine bay that looks like a regulator. There are a few screwholes on the driver's strut tower, it may have had one previously. I've pulled quite a bit of extra wiring out over the years, from when it was a rally car (driving lights, relays, etc)

I did have one win tonight - I've been trying to find the wire that runs to the "charge" light in the dashboard by connecting 12V to each of the spare wires in turn and seeing if the light comes on (without success). Installing a tacho tonight and thought I'd check the dash lights while I was at it - the charge light globe was blown, so my testing was never going to work.....

This is the alternator I'm putting in, apparently its a fairly common Bosch one. Bolts straight in with just a pulley swap.

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

That bolt that's off to the RHS should be the Earth mate. Looks like if its not there, it'll be back on the original car somewhere. I'd just make up a cable.
Yeah, blown charge light will do that to you! Glad that's sorted. Charge light wiring in the dash will be same as all the other Nissan's, thin wire, white with red trace.

Ok the new alternator:
L is the charge light hookup. You can test that as when the alternator is charging, it'll put out about 6.4v. Make sure you run the 100k resister parallel to the charge light globe. (it should be there if original)
S is the sense. Advisable to run a 10amp fuse in line with that straight to the battery.
The bolt is the earth.
The big one is the power - run that straight to the Battery and as per the above diagram, will bridge to the starter. Normally with about a 70amp fusible link.

The Datsun wiring that Graeme posted above will be for your original wiring and external regulator. Hence the yellow wires, black/white, White red (which i thought ran to the ign. barrel) and the two smaller black ones.

The rest should be easy enough to figure out!

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18

Ta, I'll have another play tomorrow night.

One more uestion - sense wire connects to battery or 12V, can this be a direct connection to the +ve battery terminal, or should it be a switched 12V supply (ie no power to it when car is switched off) ?

_________________
1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

Either. Easiest way is back to the battery and i'd still fuse it with 10amp fuse just to be sure. The S13 does this. When i rewired my car i ran it back to one of my fuse boxes, but essentially it will just read how much drain is on the battery and the regulator will compensate accordingly. So it can go onto any +12v source.
I can't remember why i went to the fuse box, maybe to simplify my fuses or to make sure that all my components were reading 12v and to sense the draw faster?

If you connect it up and put a multi meter over it, it will read 12v+

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18

I think from 69 and onwards 1600s used a fuseable link in the loom directly off the + battery then it went to starter solenoid and off there to the alternator.

Woo hoo, getting closer.

Looks like it was converted to internal reg before I got it. Whoever did it seems to have unwrapped the tape off the wiring harness in front of the driver's strut tower where Nissanman said the reg should be, cut all wires going to the regulator, tucked them away and then wrapped the tape back over the harness - effectively hiding the wires completely.

Now that I've traced the required wires, tomorrow's job is to wire it up properly. Then tackle fitting the tacho.

Mine is a 70 and does indeed have wire from alt to starter, then to battery via a fusible link.

I removed a few bits for troubleshooting......

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

Hi Dave
If you have a look at the attached wiring diagram, I think you will find that one side of the charge light will be connected to the 'L' terminal on the alternator and the other side will be connected to a switched 12 volt supply.
I believe how this works is that if the full output voltage of the alternator (when the engine is running) is on one side and (essentially) the battery voltage is on the other side, then the voltage on both sides of the globe (or meter) is essentially the same, so it will show zero but when the voltage from the alternator goes to zero then the full battery voltage will appear across the globe. If the alternator had a dicky voltage the globe will glow according to the voltage applied to it.

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1971 Datsun 1600 http://ozdat.com/forum/viewtopic.php?f=59&t=34174

Thanks, just what I need - dummies guide to alternator wiring

Hoping to get it sorted tomorrow.

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

Muzdat is correct. +12v from the gauge power on one side of the light. The charge light wire to the other. When the alternator isn't charging that wire will be earthed and the light will come on to indicate that. When it starts, it will put out 12 volts (it isn't always 12volts though). Therefore, positive and positive = no current. So the light can not work.

It is important to put in the 100k resistor in parallel to the globe. That will balance the power if the charge light power isn't 12v (mine was 6.4v) and it protects the alternator if the globe blows as it will ensure that it always reads some voltage.

It's listed in every nissan wiring diagram for a charge light.

In that schematic that Muzdat has listed for the SR. The resistor is indicated next to the bulb as the zigzag line.

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18

Hey Dave, sounds like you have probably got it all sorted now but would you mind posting a pic of the fusible link you mentioned above. Not sure what I'm looking for but my 71 doesn't seem to have anything between battery, starter or alternator and just want to see a pic of exactly what I should be looking for.
Cheers Mate
Mick

See my pic posted above: the fusible link is located physically at the starter motor terminal.

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net