I recently converted my1958 C12 from a 6v to 12v and am getting disheartened with ongoing problems. I had difficulties kick starting - it kept slipping, so I dismantled the primary chaincase to find that the alternator had melted. I cleaned the rotor to remove the debris. I'm struggling to find out what caused the problem and would appreciate any help. The alternator recommended and fitted was Lucas 47205. The Lucas rotor fitted was 54202299.
I can only imagine that the rotor and stator were not centralised ie air gap between the two components.
Check also that there is no radial play in the main bearing. The minimum clearance between the stator and the rotor is .008".
There is useful article on setting it up here : [url]http://www.klempfsbritishparts.com/Content/EDocuments/TechInfo/LUCASSTATORROTORINSTALLATION.pdf/url]
When you say 'Melted' do you really mean 'Burnt'. If the windings have become hot, it could be that you have a short in the wiring system. Check the output wires to see if any have been getting too hot... Or are you just overloading the system with say 6 headlamps..?