I have had my '94 XJS in storage for the last year. I start it and run it for 15 minutes every 2 weeks. On start up, I have heard some screaching that goes away after a minute of running. Now I notice no alternator charging, and the temp gauge starts to climb after 10 minutes of idling. But the screach is gone. But checking the waterpump and alternator today, I made the discovery they are not being driven, but the belt is still there and appears to be tensioned. What am I missing here, how can this be possible? The engine is still running smoothly.
What engine do you have? If it is the V12, it is most likely a bad harmonic balancer. I had a bad one, and found that a new one is NLA. I forgot who did it, but I had my old one rebuilt, and it works fine.
You can test the old one easily. Put a chalk or white-out mark on the outer rim, and have a second mark lined up with the first on the inner part of the balancer. You should have a mark on each side of the rubber. Start the car, shut it off, and see if the marks are still lined up. If not, you need the balancer.
You can look in the archives on how to remove the old one. When I installed the new one, the bolt was too short to pass through the balancer into the crank. I bought a longer bolt at a hardware store and used it to crank the balancer for enough down so the original bolt could get a bite.
If it is a V12 only the alternator is run via the bonded portion of the damper. The water pump is run by different belt via pulleys bolted directly to hub.
4 litre six appears to run only one belt, if that’s it Maynard’s advice/fix would still be valid.
With more load on the bonded pulley than a V12 the following may not be possible but I rebuilt the unit on my XJRS using heat cured polyurethane and have had no trouble in the 3 years since.
I want to rebuild mine as well. Do you recall any more details of how you rebuilt yours, what poly product you used or any tips on What not to do?
Jaguarrr
I turned up a disc from nylon to locate and centre the hub to outer pulley. Blasted and primed bond area, preheat parts and mix poly and pour into cavity and into oven to fully cure.
Poly is selected to match shore hardness of original bonding. I can dig up original details of mix etc. if l still have it if you like.
Not pretending to be an expert on the subject but all has been good for around the 3 years since doing the job.
Sorry I did not specify my engine specs, it is the AJ6. Thanks for all the replies received so far. I would have never guessed that Jaguar uses a two-part balancer joined by an elastomeric. I have found several suppliers that offer a rebuilt balancer for under $300, is this a fair and usual price?
The dampers are NLA from Jaguar so I always just send them to DALE MANUFACTURING or DAMPER DOCTOR.
I am in the US (TEXAS) so they are within cost effective shipping distance.
The charge for repair (with shipping) is around $200.00 US.
I don’t know where you are so that might be a good price for rebuild.
bob
In UK are reworked damper is available at around £85.00 with a surcharge on the old unit returnable after inspection to establish if serviceable.
Considering the dire state of the value of the pound these days that’s a reasonable price, I think.