[Healeys] Alternator Pulleys

[R. Lindsay]

I have installed an alternator in my BJ8 to support ac with mixed success. Since our cars use a v-belt system I had to replace the pulley that came with the alternator(serpentine) with a v-belt pulley.  I have checked the power the alternator and at idle, it is below the amperage needed to run the equipment I have installed. 

When I look at the circumference of the v-belt pulley and the serpentine pulley, the v-belt is definitely smaller. Should I use a v-belt pulley of similar size?  Increasing the circumference of the pulley will make the alternator spin faster and maybe solve my issue of slow engine speed/low amp output, I think.

If my thinking is correct, how big of a pulley should I use?  I presume that if the pulley is too large, it may make the alternator produce too many amps and damage it.  Should I match the size of the serpentine pulley or buy a pulley based on a calculation?  (FWIW, I have no knowledge/experience to do this). 

The pulleys on the crank and water pump are standard Healey. There is ac installed and the pulley on the compressor is larger than the old generator. I have a two belt system so the alternator is belted to the compressor which if what I said above about larger pulleys spin their equipment faster, how should this be accounted for?

I may be over thinking this but I would like to run the ac at a reasonable idle. Has anyone approached this and came up with a resolution?

Thank you so much for any light that can be shed on this. 

Price Lindsay

Cell: 630-841-6300
Email: 050.rpl at gmail.com

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