Lucas RB340

[DFigueira]

Hi everyone,

So after a few years, I'm finally around my R4 again. It's a 73 1125s swapped to a 845cc (old engine was literally rusted away and found a last year renault 6 845cc in a junkyard).
So when the engine was removed, not a single wired was marked on what was what. And to help me with that, the car has been fitted along the years with a Lucas RB340 box. I've figured out mostly everything, except where should I connect the alternator and coil wires (wiring is not my strongest but there's no available electrician to come where the car is) since the Lucas (original box) references a dynamo but since all wires from the alternator and coil are out, I'm not sure if only the alternator should connect to the box or if I'm missing something.

But I think the real question is - is there some kind of schematic that could help me? I've found some spanish ones (since 1125s is called a spanish model) but they are really faded and can't figure out what connects to what.

Thank you very much!

 

[Oldploggin]

The Lucas RB340 regulator goes with a Lucas C40 dynamo not a alternator most Lucas alternators came with the regulator built in and are very simple to wire up

 

[angel]

The RB340 regulator works with a dynamo only. I guess your "new" engine has an alternator. If it's the type with separate regulator, you will need a proper regulator, too, if it's the later type with built in regulator you can wire it on the existing harness with 1-2 modifications. A photo of the alternator will help.
There are two wires on the ignition coil: one comes from distributor and is connected to coil (-) or RUP terminal, other one is a switched 12V feed and goes to (+) or BAT terminal.

 

[DFigueira]

Ahh... I didn't know about the dynamo. I read about it but never assumed it was needed.
Anyway, I think I have it somewhere and didn't scrapped it with the engine.
I'll also try to get photos. It would be awesome to get this going with minimal wiring necessary since I suck at it.
Thanks!

 

[orsome]

Lucas was a good Apostole but bad electrician

 

[angel]

Better to stay with the alternator of the current engine. If your old engine was the correct for the R1125 (852cc), it turns the other way round on the 845. You will have to do an internal modification to the dynamo to make it charge, that is more difficult than adapting the existing wiring for an alternator.

 

[DFigueira]

I still don't have photos...

Better to stay with the alternator of the current engine. If your old engine was the correct for the R1125 (852cc), it turns the other way round on the 845. You will have to do an internal modification to the dynamo to make it charge, that is more difficult than adapting the existing wiring for an alternator.

So to make the change back - what would I need to change? I'm assuming that the old wiring from the 852 is all intact, except the around the lucas control box. However, If I am not mistaken, I have also any eletronic parts that came from the 845cc.

 

[Oldploggin]

Still not clear what you want to use
If you want a dynamo you will have to use a Lucas one to go with the RB340 usually a C40. You cannot use a continental one they are wired differently.
If you want a alternator a later type is preferable as they have more currant output the diodes and control unit are all incorporated into the one unit and are very easy to wire up
But you must take the RB340 out of the system
If you still want the dynamo and it is not a Lucas you will need the correct control unit to go with it they are all fairly easy to wire up

 

[DFigueira]

I have to use an alternator from what I understood. Since the 852 rotates the other way around, the dynamo won't work as is.
So current idea - what do I need to make it work with the alternator other than removing the rb340? Or is there a schematic I can use to try to figure out. Because I think aí have the old eletrónics from the car I dismantled

 

[DFigueira]

Here are some photos on how it looks right now. I can't find the dynamo but doesn't matter anyway

 

[Oldploggin]

Some one may wish to correct me but if you have a basic meter and the battery connected the thick pale wire on the back of the dynamo should be going straight to the RB340 then the wire marked B goes to the battery +
If you remove the small green wire from the dynamo and (with the ing switched on ) flash it to earth the red ing light on the dash should light up
Depending on which alternator you use if it has two terminals one large and one small plus a earth terminal connect the two large thermals on the 340 together and take to the alternator and the 2 small green ones together
and connect to the small terminal on the alternator
If you want to use the dynamo shown in the pictures it can be made to run in either direction by polarising it ( refer to flemings right hand rule to understand it better ) I repeat correct me if you feel I have got it wrong

 

[DFigueira]

Some one may wish to correct me but if you have a basic meter and the battery connected the thick pale wire on the back of the dynamo should be going straight to the RB340 then the wire marked B goes to the battery +
If you remove the small green wire from the dynamo and (with the ing switched on ) flash it to earth the red ing light on the dash should light up
Depending on which alternator you use if it has two terminals one large and one small plus a earth terminal connect the two large thermals on the 340 together and take to the alternator and the 2 small green ones together
and connect to the small terminal on the alternator
If you want to use the dynamo shown in the pictures it can be made to run in either direction by polarising it ( refer to flemings right hand rule to understand it better ) I repeat correct me if you feel I have got it wrong

Quick question - that's a dynamo? I thought it was an alternator (it came like that with the engine)

EDIT: Hope I'm not being dumb/confusing with all these questions but it's the first time messing with anything pre 80s (I've messed mostly with Hondas since I have a few myself)

 

[malcolm]

You do have a dynamo not an alternator. The dynamo is DC and needs the voltage regulator box mounted on the firewall. An alternator charges in AC and has an internal rectifier that does away with the need for the regulator box. So you are looking good.

Which wires are you trying to figure out?

 

[DFigueira]

Do late 845cc still use dynamos? Because that's straight from the Renault 6 I dismantled.

What's connected to the control box is done (except earth which I know). I wired the starter but I'm not 100% if it's correctly because of the box.
This also means I'm still missing the coil, distributor, dynamo and battery connections that I could be missing. Oldploggin already gave some lights on it.

And I appreciate the help! Never been let down here

 

[malcolm]

I've attached a PDF of the wiring diagram for a 1973 car which is probably close enough. Renault copyright but I'm sure they won't mind us using it to keep their cars alive for 50 years.

 

[DFigueira]

Thank you very much! I'm going to see if I'll get somewhere this weekend. Way better schematics than the spanish ones

 

[angel]

This is a dynamo, too. It can work with the RB340 regulator but will need an internal wiring change - not the easiest task if you are not familiar with electrics. Better to find the matching regulator for it.

 

[angel]

If you want to use the dynamo shown in the pictures it can be made to run in either direction by polarising it ( refer to flemings right hand rule to understand it better ) I repeat correct me if you feel I have got it wrong

You have to reverse field coil connections in the dynamo, too.

 

[DFigueira]

You have to reverse field coil connections in the dynamo, too.

What would be a matching regulator? Any part codes I can look for?
And would that be sufficient?

 

[Homegrown]

Confusing with language.
What you refer to dynamo, is in Sweden a alternator.
What you refer to as alternator is in Sweden a generator.

I think there is same problems with some other languages. So pictures may be needed to sort out what each and every means.