10 replies to this topic

[bikenutmart]

Hi, I have a Dec 72 (L reg) Mk 3 850 roundnose, should it be alternater or dynamo, it has a control box fitted which I think were only used with dynamos, but has an alternater fitted, the Haynes book of lies says that only toggle switched cars had dynamos but mine has rocker switches, the engine no. is 85H613E-H190. Cheers Mart.

[Gremlin]

Pictures would be a great help, what does you alterantor look like, ally casing? what sort of wiring connections?

[bikenutmart]

It is a std. lucas alternator and plug, but why the control box, car not with me at paintshop 60 miles away!! Mart.

[carbon]

Mk3s changed from toggle to rocker switches in mid-late 1970. Not sure when there was general change from dynamos to alternators but this happened later.

 

If you have control box fitted then chances are it was originally fitted with dynamo, and has been modified for alternator.

 

If you're planning to use it regularly at night then would recommend sticking with the alternator.

[RedRuby]

Details from Guessworks data base for your engine number

A series transverse mounted
HS4 FZX1142 carburettor, tamper proof capstat, ADH needle, red spring (1976 on)
Lucas C40 Dynamo with -be Earth
Mechanical petrol fuel pump
Automatic gear box mk11 b
3.27.1 final drive

Edited by RedRuby, 10 December 2014 - 07:26 PM.

[KernowCooper]

The quick mod from Dynamo to Alternator you could just leave the control box there and modify the existing wiring at that point, you can also remove it and run new wiring to the alternator and remove the box. Up to you really if your happy as it is or prefer a cleaner look its not that difficult.

[Rog46]

I've a 1972 850 round nose. - Rocker switches and dynamo!

[bikenutmart]

Brilliant!! Thanks for all the info, Im really wanting to get it all back to std. so am thinking of refitting a dynamo, I do have one to hand, what sort of job is it? Im pretty good with electrics, so feel I could do this backwards conversion. If any sort of wiring diagram exists for it, that would be really helpful. Cheers Mart.

[bikenutmart]

Forgot is the coil mounted on the dynamo?

[Guess-Works.com]

The alternator is a lot better than a dynamo, if you want it to look original then there are alternators available which look like dynamo's...

 

http://www.accuspark...k/dynamator.htm

[Rog46]

My coil is mounted on the dynamo.

 

I think the biggest issue may be getting the bracket for the back (non-pulley) end. On conversion you get a new bracket as the alternator is much shorter. I've never seen one second hand so you'll need to buy one new. The electrics should just be a case of reversing the connection changes. Lots of instructions about to do the dynamo to alternator conversion, follow them "backwards"  if you understand what I mean.

 

If you have any problems pm me and I'll look at the wire colours/terminals etc on mine.

 

I've kept mine standard, but  I keep it in a garage with one of the latest maintenance chargers connected permanently. I'd have second thoughts about the conversion you're contemplating if it was a daily driver!