I have a 2001 VDP S/C and I am trying to verify which idler and tensioner pulley I should have for the supercharger. The idler pulley is grooved but the tensioner pulley is smooth. Should the Tensioner pulley also be grooved?


I am wondering if the PO upgraded the idler pulley at some point but not the tensioner pulley.


I bought a new belt that is ribbed on both sides (Dayco B009GVFYG) but it is too long (53"). The existing belt on the car (Jaguar NCC7740AD,dated 4/2008)) is about 1" shorter and is a single sided grooved belt. So the smooth top of the belt is running against the groves of the idler pulley.


I am running an undersized top pulley on the S/C but I don't think that accounts for the new belt being too long as the existing belt runs fine


Thanks for any insight on this

 

The smooth side of the belt runs against the idler.

So either the belt is inside out, or the belt is routed incorrectly. The downloadable specifications booklet has a diagram of the correct routing.

There have been two versions of the drive. The original was smooth idler requiring
a single sided belt. This was upgraded to a system that required the replacement
of several components and the double grooved belt.

It seems you have the double grooved system, but it had a single grooved belt
installed to take up the slack when the undersized pulley was installed. That may
be why you are shredding belts.

 

The serpentine belt and the SC belt had been on the car for the 5 years I have owned the car without issues. Last week something (freezing weather) caused the serpentine belt to jump around and that damaged and then shredded the belt. When it went it damaged the S/C belt so I have to replace it.


The smooth top side of the S/C belt has ran against the grooved idler pulley for 5 + years without any wear (even with the smaller upper pulley) until the serpentine belt attached it.


I am just wondering why the double grooved belt is too long (53' vs. 52")

 

"The idler pulley is grooved but the tensioner pulley is smooth. Should the Tensioner pulley also be grooved?"

Are you sure you have this right? The tensioner pulley should always be grooved. It is the idler pulley that is grooved if you have a 2-sided belt, and NOT grooved if you don't. The idler pulley changes to match the belt.

In the picture below, bottom left is the tensioner. Above is the idler (smooth), above that is the supercharger. (this is the setup for a one-side-grooved belt)

Edit : somehow the pic turned around 90 degrees. So bottom left is now top left, unless you turn the monitor around!

 

My car is opposite your photo. Idler is grooved, tensioner is smooth. This is bizarre.
The original owner told me he had all work done by a JAG dealer. The belt that has been on the S/C since I bought was dated 4/2008 so it was not original.
I installed the smaller pulley on the S/C and re-used the belt that came with the car - never touched the pulleys

 

Mine is like Mark's. Factory original configuration without the aforementioned TSB applied.

 

Do you think I should replace both the idler and the tensioner pulleys? The belt from 2008 showed no signs of wear even though the smooth outside ran against the grooved pulley.


The only reason the belt was damaged is that the serpentine belt shredded and wound itself under the S/C belt

 

I wonder if I could just swap the pulleys (move the ribbed pulley to the tensioner)? Both would need to be inverted

 

Here are my identification notes from doing the job. Maybe the pulleys got reversed
on installation. Be careful one of the tensioners has a left hand thread bolt, but
I forgot which, and my notes are contradictory.

 

My idler pulley is 88.40 (top of groove not outer flange) mm and my tensioner is 76 mm.

 

see the ac tensioner dimensions. your sc tensioner seems suspiciosly similar.
maybe the pulleys got rearranged.

how about posting a picture like Mark's?

 

Here is a photo - my new 1 sided belt is installed . The tensioner pulley may appear grooved but that is because the paint is worn off where the belt ribs contact the smooth pulley