This is another episode of Rose's road to recovery. While the engine starts at first crank, I can clearly hear irregular rattling sound from the engine which does not go away even after reaching normal temperature. So I ordered an upper tensioner and have it installed by my mechanic as per instruction on the TSB. The mechanic has the same strange finding as Grant's in a his previous post and word-file write-up under the thread Installing (revised) upper chain tensioner
about the direction of the spring inside the original tensioner piston, but the new one went in fine; just the rattling sound is still there, only subdued. My mechanic and I listened to the rattling noise carefully and he felt that it came from the Supercharger; whereas I found the noise much louder hearing from the floor. My question is, how often could it be related to the Supercharger, or the lower chain and/or tensioner? Current mileage is 170,000 Km.

 

Well, sounds like you've already addressed the first typical issue, which is the upper tensioner with the improved unit.

The Eaton SCs have a coupler in the nose that can go bad, and often does on some models, but less so with the coupler fitted to the Jaguar unit. That being said, I have heard of the coupler wearing out, and when they do it sounds like a tensioner or bag of rocks. The best way to tell is put a mechanics stethoscope on the nose of the supercharger to see if the rattle is from there.

Good news is that no major harm to anything is happening when the coupler in the SC nose wears out, although the SC obviously is no longer working well or at all. The coupler can be bought and is a reasonably easy job to replace.

I haven't seen any write-ups on replacing the Jaguar SC coupler (although there may be one) but a quick Google of the subject will show many other rebuilds for other similar Eaton M90 SC makes (usually GM) .

Most other makes use a solid plastic puck for the coupler, which are available as cheap kits on eBay, etc, but as I recall the Jaguar unit is spring loaded.

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I agree with Al,

Noise at idle after the new upper tensioner has been installed is not common at all.

Providing that new unit has "fired off" properly, any residual noise will be either:

Lower tensioner. It is NOT pressure fed, and they do jam up.
The blades etc are worn, and at your kms, maybe.
Oil pump chain rattling, it is only a narrow single row chain, and the damper pad is so-so at best.

I would remove the S/C belt, and start the engine, note any changes to said noise.

As you have read, mine needed the lower bits doing, and that shut it up 100%, and the current owner has now got 246000kms on it, and its silent. Coming for a service next week.

 

I have ordered an M90 supercharger repair kit from eBay where the seller has some good DIY-instructions available on Youtube. The kit includes bearings, supercharger oil, and the coupler. Will see if it would stop the rattling.

 

I found a timing chain kit on British Parts that has everything including tensioners, dampers, guides etc., but even available as a money-saving pack, it is not cheap (parts + shipment) and from what you and some others have described it will be a very laborious job having to be done right. So at this stage, I just wish it were the SC coupler and the oil pump chain/damper. I shall probably know in about two weeks.

 

Just a quick thought.....

On my XJR/6 all of the drive belt tensioner/idler pulley bearings eventually failed. I recall three in all. Sometimes they gave a grinding sound, at other times a very distinct 'rattle' sound which could be mistaken for timing chain noise

Just for the heck of it, and before getting elbow-deep in engine innards and timing chains, remove the drive belts and spin all the pulleys. Or leave the belts in place and use a mechanics stethoscope for a good listen with the engine running. Maybe, just maybe, you have a rattly pulley bearing

Cheers
DD

 

i had the same problem,i replaced the tensioner,still rattled,from this forum i had read that the oem oil filter was the best available,i installed the,"manne",filter,and the rattle went away on the first start,...hope this helps.

 

Adding to Dougs findings.

Remove all the belts, start the engine, note the noise, or lack of.

It will be fine for the short running it will take to determine if the noise is Internal or External.

My A/C belt idler was a groaner, and thinking back, it took some searching to find it, as it anly groaned under tension/load, not when being spun in the hand.

 

Thank you. I am afraid it wasn't the filter. In Rose's recovery, the first thing we did was to replace all fluids and filters, the latter all bought from British Parts as factory original or OEM. Price difference between Jaguar and OEM filters is very small, by about GBP1.5. BTW, British Parts' Filter Service Kit seems to be of good value; GBP20 will buy you the air, fuel and oil filters, O-rings as well as the sump drain plug washer. There would be many good and reliable after-market replacements available in the US, I believe.

 

Thanks all for the heads up. Will certainly see if the pulleys/idlers are causes of the noise, or needing attention or replacement because of the mileage.

 

The supercharger coupling can make a noise, but it's definitely worth checking all the pulley bearings. I have had one go bad at 137,000 km.

 

Here is an update on the engine rattling sound. Only the upper tensioner was replaced so far; the mechanic has advised not to disturb the lower tensioner, timing chains etc. yet but simply help Rose regain internal lubrication and heat/cooling cycles through more regular use. Tracing of the rattling is now narrowed to the box next to the inlet manifold. Wonder what would cause it as the parts diagram does not show there being moving parts inside or down under.

Rattling apart, the engine runs very well and I can feel the immense power that I can use if I dare - Andy's special ECU has taken care of the timing advance. I have actually bought a 3.58 differential as a future upgrade but I now believe that it wouldn't be necessary as Rose's very powerful torque has made it possible to keep the engine pulling effortlessly on 4th or 5th gear even on low revolution. The 3.58 differential, if installed, would make the 1st gear redundant.