Alternator Pulley Interchangeability - 02 Boxster S Manual

[Lotus26R]

Hi. I was supplied with a replacement (recon) alternator for my 2002 Boxster S but it had the solid pulley fitted instead of the freewheeling / overrunning clutch type.

My garage fitted it anyway but found that it only charged at 8.4 volts. The alternator supplier is telling me that the reason it only delivered 8.4v was due to the incorrect pulley being fitted rather than any internal fault with the alternator which I find difficult to believe.

We fitted another alternator with the correct pulley & this one charges fine.

Has anyone any experience of running a "solid" alternator drive in place of the "freewheel" type please? Does it in fact result in a lower charge output or is this a red herring by the alternator supplier to avoid picking up the second set of labour charges.

Thanks

[RFM]

Strictly speaking there should be no noticeable difference in voltage, the freewheel pulley ensures a quiet and vibration free, and therefor less stressful for the belt and rollers, operation, especially when downshifting (engine braking). Anyway, keep always in mind that alternators with a "solid" pulley needs metal rollers, alternators with a "freewheel" pulley can use both, plastic and metal rollers. Plastic rollers are not resistant against the more rough operation of a alternator with a 'solid" pulley.

[JFP in PA]

Hi. I was supplied with a replacement (recon) alternator for my 2002 Boxster S but it had the solid pulley fitted instead of the freewheeling / overrunning clutch type.

My garage fitted it anyway but found that it only charged at 8.4 volts. The alternator supplier is telling me that the reason it only delivered 8.4v was due to the incorrect pulley being fitted rather than any internal fault with the alternator which I find difficult to believe.

We fitted another alternator with the correct pulley & this one charges fine.

Has anyone any experience of running a "solid" alternator drive in place of the "freewheel" type please? Does it in fact result in a lower charge output or is this a red herring by the alternator supplier to avoid picking up the second set of labour charges.

Thanks

That is nonsense, the alternator was bad.

Edited July 7, 2012 by JFP in PA

[Lotus26R]

Thanks for the prompt response guys. I didn't see what difference it would have made but it's always useful to have your opinion "sanity checked".

RFM - are the "rollers" the idlers on the belt drive system please? Mine were changed during the repair for units costing £56 each but I've no idea what they were made of (nor the part numbers)

[RFM]

The rollers are indeed the idlers on the belt drive system, just as you say.