Hi,

I have a 1995 XJR6 which has seen better days, but at least the top half is presentable and the electrics all seem to work, although I haven't been brave enough to try the sunroof.

Interestingly (worryingly maybe) the supercharger belt is missing. Superficially things look OK, apart from the item highlighted in red on the photo. It seems to be a bit scorched and doesn't turn. If you know what it is, please let me know. Should it turn? I presume so.

Thanks for any help.
Richard.

 

Looks like an idler pulley and yeas it should turn

 

To be precisely, it is the remnants of an idler pulley - just the bearing remaining it seems.

 

Genuine Supercharger Belt Tensioner And Idler Pulley (4.0 Litre Supercharged,4.0 Litre Supercharged (e/evap)) For Jaguar Xj 1995 - 1997 (from 720125 To 812255) Classic | Jaguar Land Rover Classic Parts

belt is here


Genuine Drive Belts-3.2/4.0/4.0 Litre Supercharged (3.2 Litre,4.0 Litre,4.0 Litre (california),4.0 Litre Supercharged) For Jaguar Xj 1995 - 1997 (from 720125 To 812255) Classic | Jaguar Land Rover Classic Parts

There may be generic pulleys available

on the tensioner for the A / C compressor belt there is a Gates #

The tensioner may take some heat and penetrate oil to loosen the long bolt adjustment block nut ( you must loosen the pully axle bolt first )

You can pound a sized socket on the square flats of the long adjustment bolt and use the square socket drive in a ratchet

 

Probably a foolish question but how does it run like this? While you're looking for a pulley, Find a belt too. Might as well replace all three belts for peace of mind.

Larry Louton

 

i would replace all three idler pulleys - if one has seized and self destructed, the others are probably not far away from doing the same.

 

Ideal, at least I know what it is the remnants of now.

 

Thanks also for the parts links. The car drives OK, given its other non-engine related issues.

 

Please check out this thread for my experience sizing the supercharger belt. https://www.jaguarforums.com/forum/x...t-xj6r-233646/

 

There is the possibility of the supercharger pully being a smaller higher performance size from the standard size possibly effecting your belt size

The belt size for the alternator is critical from reading and off the top of my head ( I wrote it down in the garage ) a official Jaguar marked alternator belt is 395 cm but I just put mine back on

There is a separate electric coolant pump on the right side that should come on for intercooler flow

I don't have the supercharger but I think they increase the size of the crankshaft pully

 

Continuing the positive theme, that is by far the easiest idler to change, and the supercharger belt is the easiest to change, so you might be in luck. Without the supercharger, the car is a bit of a slug due to the lower compression ratio of the engine, so definitely worth fixing.

 

Many of the pullies used in automotives are amazingly standard and have a 17mm bearing bore. I changed the original plastic pulley for a metal one. It's 90 mm diameter, the one I used is Gates 38001. Application is a 2000 Chevrolet Silverado with 4.8. It's the smooth pulley.

 

See page 28 of the 95 LWB doc

 

Looking Parker's diagram above, see that it may be possible to reduce the size of the upper SC pulley by, say 0.5 inch. Assuming the pulley was 3" and is reduced to 2.5, and knowing that the belt goes around half of it, the original belt will now be too long by (3π - 2.5π) / 2 = 0.8" roughly. Far from the 4" I experienced by buying the belt by part number. Buy by stated length instead.

I believe the usual mod is to increase the size of the lower pulley, which would make the recommended NBD7740EA too short by even more than 4".

 

When I bought the Powerhouse lower pulley it comes with a new belt

 

With the destruction of the idler pulley and the fact no one replaced it I would question if the SC even turns? Looks like the pulley locked up. Destroyed the pulley and then broke or threw the SC belt at the same time?

Not a good sign and it seems the car was not taken care of very well.
Might be worth pulling the SC for a good inspection and maybe consider a bearing replacement or even a complete rebuild as it's so old at this point?
For SURE change the oil in it!
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Supercharger oil change before and after light run in ? The oil is probably not cheap

Is it possible to run in the supercharger without the belt and a side load on the blower bearing in question.?

Or damage already done to the point of bearing replacement based on assumption and be just as quick to have a new bearing

the fact that the smooth idler pulley is missing at the bearing outer race points in the smooth idler pulley bearing direction

Just spit balling

 

It's not bad, it's AC Delco supercharger oil, as the SC is the same as used on Buicks and Ford Thunderbirds. It's been a while, but I think it was around $10 a bottle at a GM dealer.

 

Can't run the SC without a belt. Yes the oil is very common and used in many cars. I also use the AC Delco stuff.
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I was thinking in terms of having the belt off and with a drill and a cloth buffing wheel on the naked pulley maybe getting it to turn and clean out the possible debris in the original lubricant

But then it may be time for a blower overhaul anyway but it might have some service life left in the blower and the cost involved

I was mistaken thinking about the cost of turbo oil

I don't have the supercharged engine