As part of Rose's recovery, and to tackle the engine rattle emanating from the supercharger, my Mechanic and I decided that it was time to remove and rebuild the supercharger and give all the hidden parts a thorough clean.

Bought an M90 Supercharger Rebuild Kit off eBay a while ago. The kit includes 2 bottles of Supercharger Oil (by ACDelco) with syringe, a large and small supercharger snout bearing, a pair of needle bearings, a coupler, Gasket Maker. Didn't take a picture of the kit when new. Here is a picture of the parts replaced.




The mechanic did not remove the inlet manifolds so moving the supercharger out and later putting it back was not smooth sailing. The airbox had to be removed. The air ducts leading to the supercharger were all replaced except one which is no longer available new.



The supercharger oil removed looked undisturbed, but had an awful odour - the mechanic said this was sign that the oil was long overdue for replacement. The supercharger only took in a bottle of new oil after re-installation.

The snout pulley and bearing were a pig to remove, and only after consulting Youtube footage could the mechanic manage to figure how to get it out - the lack of proper tools made this step a huge challenge.



The factory original coupler showed signs of extensive wear including a hairline crack, and it was replaced with a new style coupler that has a built-in oil seal.






The needle bearings were badly worn, and were replaced. These needle bearings ensure seamless and smooth revolution of the moving parts within the supercharger, as any play would cause vibration and unwatned wear. It was said that the supercharger turns 5 times faster than the engine speed. Removing the needle bearings was relatively easy - just hammer them out, but getting the news ones back in and ensuring that it go straight in and sit tight required a special tool. The mechanic made a quick visit to a machine shop and quickly fabricated one.





The opportunity was taken to replace the stepper motor (Idle Control Valve), and give the throttle body a good clean. X300 NA versions are luckier as there would not be the supercharger that is in the way.






Then the supercharger belt was replaced. We then had a problem with putting in a new alternator belt. The OEM size proves too long (5PK975). Eventually found 5PK960 as 5PK970 was still loose and size 5PK965 was not available. I had another thread about this a few days ago.

The result is a quieter engine and perfect idle. Lesson learned is this is not a job that should be attempted without proper tools. There were signs of wear within the supercharger as some object fragments might have been drawn inside and caused wear. The time cost of the rebuilding process might have justified buying one new. Saw a brand new supercharger M90 on eBay Australia a year ago asking for about US$1000, but of course if new ones are no longer available (now rare as gold) rebuilding the existing ones would be the way to go.

 

Hello Qvhk, This of great interest to me, I was planning the same operation on my 95 XJR
engine but I have collected a nylon coupler instead of a spring loaded coupler that you have shown. Where did you find yours and is a part number available for such?
Thank you. Larry Louton

 

The nylon coupler is part of an M90 Supercharger Rebuild Kit commonly available on eBay. I cannot find the previous kit which I bought, but this eBay listing looks similar and has all the parts you need including the needle bearings, new style nylon coupler, supercharger bearings, etc. I also found other new offerings on eBay including a new Supercharger nose which would take away the trouble of you removing the old pulley and replacing the inside bearings yourself.

 

...another option if you are happy to pay is send to dynobob at Steigermeier.com for a full rebuild , he can also do porting and a water-cooled drive snout (“Venom” cooler), plus machine a smaller pulley (2.4” instead of 2.8”)
He quoted me about USD$1595 for this from memory, plus shipping.
It’s appealing, I’m just feeling a bit tight at the moment, and want to do extractors first

 

sorry off topic;
Al; (maybe stupid question but)
for the Venom cooler; did Stiegmeyer take in account that the jaguar sc snout is shorter than in the eaton m90 model used in buick for example?

or is the idea to modify the old snout?

and based on quick read on some other forums is that the venom cooler is not doing much/anything for the IAT:s

 

AnttiM,
I need to send my old snout, or whole supercharger, so I presume they modify the old snout. I have questioned him via email bout the short snout of the XJR6 Eaton, seems to be no problem.

After reading your post last night, I googled IATs and Venom. I couldn’t find out much.
My understanding, having done Physics at high school level, is that most of the heat in a supercharger is due to Boyle’s Law - compress a gas, and it heats up. Conversely, let it expand, and it cools, like the neck of the BBQ gas bottle.
Bob Stiegemeier states that a lot of the heat is from the drive gears in the snout, and that the cold induction air coming into the rear end of the supercharger keeps that end relatively cool, so there is quite a temp gradient from the hot, front drive end to the cooler rear end.. the Venom cooler is just a water jacket in the snout drive casting , plumbed in to the intercooler water circuit, which cools the snout directly, and indirectly must draw some heat out of the body of the supercharger into the snout. So it reduces heat sink, rather than cools the charge, like the intercooler does.

My summer here at the moment is about 30’C. Last summer I replaced my very tired OEM Hella IC electric water pump with a Bosch, which has virtually eliminated loss of power on repeated burst of full throttle. However on a cold wet winter’s day, the car goes like a rocket. To really cool the air charge, something like Killer Chiller or methanol injection is the way to go, I guess. I can’t face all the hassle, and don’t want a drag car!
My take on the Venom, then ,would be that it really would just be to keep excess heat out of the drive end of the Eaton, improve its longevity, and perhaps reduce IATs 5-10’C for a smudge on more power.

 

Down here in Florida, My XJR engine is noticeably faster right before a rainstorm. Whereas the humidity even gets denser and colder. When I do my supercharger rebuild, I am planning on upgrading to the Bosch pump and a stand alone cooling system plan for the intercooler. Speaking of IAT temperature, My vehicle runs at 165 degree'F or about 75'C. Have you ever monitored yours with a scan tool?
Thank you in advance.
Larry Louton

 

Found that spring torsion isolator that I so coveted. Reread your article and would like to know if you used the grey coupler, The green coupler or the spring coupler?

 

I am waiting for a PLX Kiwi 3 OBDII device to arrive in the post from the US of A.
Once that arrives, hopefully I will be able to tell you my IAT.

 

Thought you were referring to my first post in this thread. I use the green coupler that comes with the repair kit, which is a new, improved design that does not need the spring (see explanation in article by www.V6performance.com.au, although I read from another article by Superchargersonline.com that green ones are imitations and they prefer to use stock coupler with the spring. I guess you can only find stock supercharger coupler from them and not from Jaguar sources.

 

found stock coupler with spring from Superchargers online by reviewing parts list for 4.2 liter and 5.0 liter. Funny how you are waiting for same scan tool I have.

 

Got my supercharger out, rebuilt and reinstalled with out any major hiccup's, Went with the green coupling because I found a wear mark from the broken spring on the impeller
side of the coupler. Did you ever receive your Kiwi scan tool? still looking for a IAT temp number? I had drained out six ounces of oil and refilled same amount, How about you?
Thank you. Larry Louton