[Vwdiesel] Free wheeling alt pulley WasRe: Re undersized
Val Christian
val at mongo.mongobird.com
Thu Aug 28 20:45:46 PDT 2008
>
> At 01:56 PM 28/08/2008 -0500, you wrote:
> >As far as pulleys and alternators are concerned, my 04 Jetta TDI actually
> >has a pulley on the Alternator that freewheels at certain speeds thereby
> >reducing the load on the engine. I guess since there is minimal electrical
> >usage on diesels they decided to save a bit. Hayden
> >
>
>
> No, it doesn't freewheel at certain speeds, it is an overrunning clutch that
> allows the alternator to overrun and slow down slower than the engine when
> decelerating suddenly, (like on rapid up shifts).
>
> This reduces serpentine belt whip, caused by the rotating mass inertia of
> the alternator and came about because of early tensioner bushing wear-out,
> and also might have had something to do with the crankshaft nose failure on
> early 1.9s.
>
> It became standard equipment on the TDIs. I have retrofitted one on my 94 TD
>
> Sandy
> VE3AAC
>
Also a major source of failure with the alternator. I put a non-freewheeling
pulley on mine, and at least I haven't had to keep replacing the freewheeling
pulley.
Val N2EPO
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