the c40 dynamo and its pulley

[dgym]

Hiya!
I've got it in my head to take my car back to positive earth and of course the dynamo/control box.
I'm a sucker for originality and MOST OF ALL I'm a sucker for a schematic that matches the car. The PO's alternator installation is also very messy.
I did get the original Dynamo with the car, painted green to match all the little bits of green I see under the yellow. I did not however get the pulley. -I think I'm also missing some brackets.
So my question is this, would the pulley be the same as that on the dynamo from my old Triumph Spitfire? the dynamos look almost Identical. Does anyone have any ideas about this?

and perhaps a source for the original mounting brackets?
cheers!
-Jim

[types26/36]

I would think that the generator is the same as a lot of British cars used that Lucas generator at he time but I think the mounting brackets for the Triumph would not be correct although the pully would be the same.
The brackets would be the same as the Fords of the time......Anglia, Mk1 Cortima etc.
If you are going back to positive ground don't forget the Rev counter will also have to be converted.

[dgym]

Thanks Brian,
yes the rev counter says "positive earth" ..I'm guessing i'll just have to connect it back the opposite way.
I think I need to find the correct control box too, I have one for the spitfire but it appears to be a match for the later Elan.

[dgym]

actually, the mounting screws on the elan line up with the spitfire control box...hmm.

[AHM]

As Brian mentioned you will need to convert the rev counter back to positive earth - what you need to know is here.
http://mgaguru.com/mgtech/electric/et202c.htm

The correct control box is an RB106.

Triumph, Mini... it's all the same except that you do need to have the correct pulley diameter.

[dgym]

cheers!

[dgym]

ok so i'm betting on this as my bottom bracket, looks like around 4 inches to the outers of the bolt holes to the engine, and 5&3/4 inches between the holes for the dynamo, which matches my dynamo.

http://www.ebay.co.uk/itm/FORD-DYNAMO-B ... 58b3637ef7

I have added a pic of my alternator setup. There's an interesting bar type mount bolted to the engine, which has been tapped at the front for the alternator to bolt into...i'm guessing this isn't part of the original setup?

Is there any chance a S3 with Dynamo owner could do a pic for me?? i'll owe you one!

cheers,
Jim

[oldelanman]

Does this help ? It's an S4 but they are all the same.....

I have added the plate between the three front cover bolts it's not original for a generator set-up but I believe it is for an alternator.

[dgym]

AH!! Fantastic Roger thankyou!

[rgh0]

Hiya!
.......
So my question is this, would the pulley be the same as that on the dynamo from my old Triumph Spitfire? the dynamos look almost Identical. Does anyone have any ideas about this?

........
cheers!
-Jim

I don't think you got an answer on the pulley. I believe the Lotus one was a substantially larger diameter than the one shown in the photo. Someone with it on a car still can probably measure one up for you.

cheers
Rohan

[AlfaLofa]

The pulley diameter of a spare dynamo I have is 3 1/4".

I have no reason to believe that the pulley has been changed.

[oldelanman]

The pulley diameter of a spare dynamo I have is 3 1/4".

Ditto....

[dgym]

thanks gents,
yes the spitfire pulley is only 3"..

and in regards to the control box, I've attached a photo of my mounting points lining up with the rb340 unit from the spitfire, so unless the screw holes for the rb106 and rb340 are the same, I guess may car had the later rb340..

would this have been an upgrade? and would using the later version work with positive earth?

(i am having trouble getting my head around positive earth, after years and years of things going to ground it just keeps confusing me)..and the wire colours... black is now positive...and red is negative on the battery connection..???????

[oldelanman]

I guess may car had the later rb340..would this have been an upgrade?

According to the parts list the RB340 control box was introduced during S4 production from chassis number 9076 but my S4, built considerably later, has the RB106 fitted.
Like many things Lotus there are no hard and fast rules

[AHM]

The RB340 has a current limiting coil and the RB106 has some kind of current compensation.

I'm sure that I read somewhere that the RB340 was fitted to the elan only as negative earth. I don't think there is any reason that it shouldn't work with positive earth, but it isn't going to match the wiring diagram....

According to the wirig diagram the S4 was fitted with the RB340... According to the parts book the RB340 was fitted from 9076 part way through S4 production so I'm not sure what my early S4 would have had. That said it doesn't mean that your car didn't have one as original it would have been a current model. My S3 has Carello side repeaters and small gauges with external lights, the headlight relay is mounted on the wiper wheel box - I think it all depends on when things were updated, who was on strike or had cashflow issues, and what was on the shelf.