Hi all I've overhauled my supercharger & was told to leave carbon on rotors, looks like rotors are rubbing on carbon build up but I left them as advised & I have got a noise at tick over from SC. used Stethoscope & noise is definitely coming from rotors.
As soon as idle is raised slightly noise stops. Also have 10% smaller pulley fitted



Carbon on rotors. <br/>Does it look excessive?






Replaced rear roller bearings. No scoring any where or play in main rotor bearing

 

I do not have a solution, but it sounds like I may have the same problem in it's beginning stages. After driving around, starting and stopping, after about the fourth restart or having driven for a length of time, when I go to shut the engine off, I hear it drag on a second and a half or so, sounds like it is coming from right in front of me, (LH DRIVE), that will go away if I raise the idle slightly, and does not always occur. Most of the time it shuts down promptly and completely after turning the key off. I am praying that it is not the s/c, but hopefully the AC, as it needs a charge, and I had a code 23 appear after I had started the AC accidentally in less than 23 degree F weather, and got the compressor lockout. Needless to say I will be monitoring this thread for information. I wonder if the belt has loosened and needs tightening, as it is intermittent at this point, and it does not occur until the motor is hot; and not on trips < 6-8 miles. I know it had a new serpentine belt installed right before I purchased it, hopefully a junk cheap belt, or they put the old one back on, and charged the P.O. for a new one, that may be slipping? I am grasping at this point, and just wish the noise would stop, without stopping the motor permanently.


P.s. Is that 'scoring' just before the needle bearings to the back of the s/c housing on the left and right sides?

 

Also, that is not carbon build-up on the rotors; the rotors in later MY XKR's are Teflon coated, what MY is your XKR? There is also a coupler that wears and needs replacing. It is located in the front of the rotor pack, the drive shaft connects directly to the s/c rotor gears via this coupling on the left side rotor, turning a gear that turns the right side rotor gear. There are several videos on Youtube, showing this coupling and how to replace it, not necessarily on a Jaguar model, but definitely on the S/C used in the Jaguar XKR, which is an Eaton M-90, or M-112, depending on model year. Someone should be along to correct the type of S/C depending on MY. Play in this coupling may account for the scrapping on your rotors, and as you will see in the videos, the first thing the mechanics want to change is the needle bearings, when it may only be this easier to get at, and cheaper fenolic doughnut that is causing the problems. Here is a link to the S/C repair compilation videos, not all the S/C's are Eaton in these videos, but pay particular attention to Jon Bond's video's as they are our s/c's:
https://www.youtube.com/playlist?lis...ZYsJ5gZRjdkoeE

There are 196 video's showing how to tear down S/C's and repair them, there are also a few video's mixed in with this link that just show S/C's whining, revving etc.
P.s. The EAVS (Eaton's Electric Assist Variable Speed Supercharger is able to replace both the alternator and starter while providing increased fuel-efficiency and power), system is a good watch, has nothing to do with our vehicles, but it is a really cool S/C system.

 

Thank you for your advise. I've overhauled supercharger & coupling.
It's a 2003 MY 4.2L M112 with helicoil gears.

 

Hi Grim, I posted this to the other thread in error, didn't see this one you've started.

As another note based on seeing your photos, the blades are fine, the coating is teflon, an upgrade on the 4.2 S/Cs. Not sure on the marks in the coating, could be where some dust or grit has been squashed through the blades during operation or could be wear in the teflon caused by slight play in the rotors. The 4.2 S/C I sourced (see below) was perfect, not a mark in the coatings and was from a 27K mileage car.

Previous message posted on S/C thread:
When I was sorting out my rattling at idle 4.0 supercharger I tried the new pulley first to find the coupler had already been changed for a solid one. This didn't solve the rattle so not the snout bearings.

Then I tried the rear needle bearings, no better.

Eventually I purchased a low'ish mileage 4.2 charger and fitted it , with the new coupler I had originally fitted to the 4.0, and the flexible coupler that came with the 4.2 S/C. This finally sorted things and it's been perfect since.

Basically the bearings pack in the middle of the S/C on my 4.0 was ever so slightly worn. Side by side on the bench I could feel that the 4.0 action was looser and not as tight as that on the newer 4.2., it didn't spin as smoothly or for as long as the 4.2. Everything still worked perfectly but I believe this slight play between the blades bearings allows the cogs teeth to chatter when idling without a load on the S/C.

A note on the oil.. I replaced the oil in the 4.0 3 times in total during everything else. Each time it was a rather murky unpleasant grey colour. I don't know why, it could have simply been colouring from the black sealant I was using or something more sinister, but I did note that the oil out of the 4.2 I bought was a lovely honey shade which made me confident that nothing was too much amiss with new S/C.

If I was starting again on another car... I'd go straight to finding a 4.2 S/C from a reasonably low mileage car and getting it fitted. Fortunately for me I was doing all the work myself... if I'd been using a garage the labour costs would have massively outweighed the cost of buying a decent second hand S/C for about £400 and it working first time.

Grab the pulley at the end of the coupler and rock back and forth, if you have a definite movement and clonk when you change direction the chances are the center bearings are loose and only a replacement S/C will solve it. Notice how many are listed on E-bay with a 'slight backlash'. I expect most of these would rattle at idle if fitted - IMHO of course.

Best of luck!