Dynamo pulley info please

[dalgrae]

Can someone please tell me the correct size dynamo pulley for my car please .At present the pulley fitted to my car on my 948cc engine is 3 7/8 or 95mm and has screw type terminals the dynamo I have bought from a club member has a pulley fitted which is 3 1/4 or 85mm diameter and has spade type terminals , also the local Morris Minor centre in Bristol is advertising a new pulley made of plastic any thoughts on these please would be welcome

[philthehill]

The difference in diameter will not make any real difference to the charging or reliability of the dynamo. More important is that the belt fits the groove or 'V' of the pulley fitted to the new replacement dynamo and its alignment with the crankshaft and water pump pulleys is correct. If all that is good I would save your money and use it.
Personally I would not fit a plastic pulley but would stick with a metal one made out of either steel or alloy.

[chesney]

Agreed, the plastic pulleys are useless, stick with a good metal one where they can't break...

[dalgrae]

Thanks for the replies I have since foun'd out they do not sell the plastic pulleys anymore but do sell the convensional fabricated type and they are 3 inch diameter ,what I am trying to achieve is commonality in so much as both dynamos being on the same pulley diameter so I only need one size of belt I can drill the large spade terminal with a hole diameter to suit the existing fixing and I intend to solder an eye type adaptor to the field spade connector so if I need to swop dynamos it will be easy to do

[philthehill]

There should be enough slack in the existing drive belt/adjusting bracket slot to accommodate both sizes of pulley; so again I would not buy another pulley just use what you have got.

[bmcecosse]

Just use it as is - the effort of changing the pulleys about is definitely not going to be worth it! And a plastic pulley ???? Oh dear