mk1-forum.net

I just bought am 80mm chrono Smiths rev counter which has a 2.5:1 ratio.

Does anyone know what size pulley I need to fit to the Lucas C40T dynamo to get it to read correctly?

As part of the same purchase I got an 80mm mechanical speedo - looks lovely, just like the ones in a '60s Lotus, but it only reads up to 60mph. It is marked on the face ' X35197 1000 ' does anyone have any means of identifying what it's likely to be from?

Photos on the original ebay listing:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEDWX:IT

Al,

Re the speedo, as its an oddball, it would be a good idea to check that it's 2.5 engine revs per tacho rev or vice versa before trying to calculate pulleys. Once you know that, it's simply a case of measuring the circumference of the crank pulley & either dividing or multiplying by the 2.5 ratio. With a ratio as high as that you could end up with a very big, or very small pulley though.

It may be worth contacting speedy cables or speedograph re a reduction / multiplication gearbox though. They will also be able to help re the part no query.