[modern] Supercharger Pulley Replacement - a warning for XJR owners

This applies to the XJR6 engine - not sure if the XJR8 has the same set-up.

The plastic idler pulley on the supercharger belt tensioner - the one
nearest the crank pulley - sheared off whilst driving along. Interestingly,
apart from a loud clunk there were no immediate signs of anything wrong, not
even a check engine light!

Without the supercharger, the engine remained very smooth but obviously
without the same power. It was quite happily driveable, other than a
reluctance to kick down where one might have expected it to do so in order
to gain power.

Talking to the dealer ( Lancaster in Reading - first class service for parts
) the lady said that failures in these pulleys were getting quite common and
they even kept the other, non-tensioner, idler pulley as a regular stock

XJR owners be warned. The pulley is a two piece construction with an
internal bearing race. It’s this which seizes, leaving the inner on the
mounting shaft and the outer somewhere down the road.

Replacement is simplicity itself, the pulley simply unbolts.

To refit, attach the pulley and tighten the bolt so it holds the pulley
square, but not hard otherwise you can’t adjust the tension. Then turn the
tension adjuster ( it’s the square headed shaft poking out of the top of the
tensioner assembly, under the top hose ) anti-clockwise so you can easily
get the belt on.

I’m not sure of the correct tension for the belt, so if someone could check
theirs I’d be grateful. For now, I’ve used the old rule of thumb which says
the belt should just be twistable through 90 degrees on the longest run.
Once you’ve tightened up the adjuster to this point, finally tighten the
pulley bolt to ensure it stays square and tight.

Haven’t been on a good run to check it all out yet, but a quick run around
the village seems to indicate everything in working order.

Cheers - Jez***************************************************************************************************
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