I'm happy to hear that the key is not in the mix. When I first saw what had happened I was concerned that I had another incident like on the Toyota I mentioned. I am reasonably confident that the crank shaft is OK.

The rubber part is confusing. Hard to figure why there would be any need for that or how it fits in the assembly. The crank drawing gives no clue. Maybe as a shock absorber? Obviously if something like that fell out the extra play would start demolishing what is left. I have been through the JTIS and haven't found anything that covers the details of the damper. The removal and install description makes no mention of a rubber part or two separate parts of the damper.

There are a couple of other threads on this forum about this problem. In those cases I believe the outcome was that the tapered split part had failed. Based on that (and the fact that the damper is completely loose) I ordered the part and have it here. How this happened is anyone's guess but I was thinking that someone prior to me had this thing off and reused the part. The split tells me that this is designed to deform slightly and lock the damper on center due to the taper. I can easily see this thing cracking due to fatigue (or maybe over-torque) and falling out in pieces. The failure was not gradual and I see no way the belts could have been aligned if this wasn't there to begin with. The split part is fairly large.

Anyway I'm going to talk to my local mechanic later today and see if he is willing to tackle this. Otherwise I'll get it hauled to a Jag specialist who is not too far away. The nearest dealer is about an 1.5 hours from here and I don't trust them anyway. The local guys really don't like this car because it has stuff like this and they see liability.

 

I talked to my local mechanic and he said he will work on it Monday morning. He has seen this problem before (I doubt on an XKR) and he is pretty sure the damper/pulley has come apart. He seemed pretty familiar with this and how they are constructed with two pieces and a rubber in between. Anyway I should have an answer on Monday.

I guess I will busy myself with figuring out where to get this thing rebuilt.

 

Is this any help??new home page H.B.

 

With just the bolt you can get the pulley on with the belts aligning, it just sounds so odd that the strong split collet has disappeared totally as its being held in place by thewide collar of the main bolt. That could only mean that the bolt would have to come out already quite some bit for this to happen. Double check the crankshaft though, as when the split collet has been in pieces as you say, it could grind of the crank.

The damper that Oldmots is referring to is the rubber between the fead belt ring and the main part of the pulley.This could degrade, and although you haven’t mentioned that the fead ring came loose (so also being unaligned) all I can guess is that he might refer to it as being a possible cause for the pulley bolt to come loose due to excessive vibrations.

 

I stopped in the shop this morning and he was busy pulling radiator stuff out of the way to get access to the damper. Better he than I.

Thanks a lot for that link to Dale Manufacturing because I am fairly sure that is the issue. I guess these things do fail enough for someone to build a business around it. I no longer think the split cone part fell out or the bolt would have been easy to remove. That was all based on some other threads I found.

I have been pondering what would cause this and I think the tension on the supercharger belt was too high. I say this because I had a tough time getting that belt off as it took a cheater pipe added to the handle of a vice grip to get it to move. That would put a lot of leverage on the outer ring of the pulley. The main sepentine belt had much less tension.

I did find a nice selection of tensioner tools (after a good amount of knuckle banging with my vice grip kluge) at Summit Racing. I ended up buying the Craftsman set for $25 because it appeared to be the most versatile.

 

Just heard from the mechanic and the taper was loose and the damper/pulley is OK.

Our conclusion is that someone prior to me was in there and didn't get the bolt torqued properly. Maybe the front seal was replaced but difficult to say. Anyway it took him about 3 hours to get it done given the correct tools and facility.

Man I hope this is the end of this.

 

Good news Walt.

 

Walt, how did he get it off?

 

Gus, he used the flywheel to lock the crankshaft.

Bad news, it did the same thing again. I decided to double check it and the damper pulley was wobbling like an old drunk. Back to the mechanic and he says it didn't look like that when he finished his test drive so it is coming back apart tomorrow morning.

The taper goes in from the front (despite the assembly drawing posted in this thread) and the shoulder on the bolt presses the taper into the damper pulley hub. He said the taper went all the way to being flush with the damper pulley so he ground down the shoulder in the bolt so it could only contact the taper and not be stopped my the damper pulley. The torque is something like 264 ft-lb so this thing should not be moving. But it is.

The best guess is that the damper pulley hub is enlarged and allowing the taper to bottom out on the step in the crank shaft such that all the torque is going against the crank instead of outward against the damper pulley. The thinking is to take the damper pulley to a machine shop and get the hub opening reduced. It's that or a new damper pulley with a list price of $1675 and questionable availability. Talk about a swing of fortune.

 

Once the Taper is the same Diameter as the Damper Bore, there will be no additional tightness possible regardless of whether the shoulder of the Bolt is reduced to fit inside the Damper.

The whole idea of the Taper is that, at the proper tightness, some of the taper will still protrude forward out of the Damper.

This assumes that the Damper Bore is uniform and does not have a Taper machined into the front of it.

JTIS refers to the Taper as a "Split Ring".

 

Sounds like you need a new crank bolt because it has now been modified, and the manual calls for a new bolt anytime that it is removed anyways.

You may also need a new split ring/locking collar ... what if someone ground down the collar to get a "better fit" because they didn't know better? Checking this may save you a lot of aggravation and expense.

 

Assuming that the collar fitted after the bolt adjustment, you can be sure that the pulley/crank had been grinded of by the earlier issue.

Is the pulley loose, or is just the fead ring (so the ring from accessory belt) wobbly?

 

The mechanic tore it down again this morning. Practice makes perfect. The hub of the damper is also tapered so a sleeve is not an option. What is happening is the tapered part is bottoming out on a shoulder on the crank shaft. This prevents it from doing its job. Likewise the bolt shoulder was bottoming against the damper and thus preventing it from compressing the tapered part because at this point the taper does not extend past the damper. This is by any analysis a very poor design. A hub with a key would not have this problem and would allow the damper to be synchronous with the crank shaft, which allows for balancing. What were they thinking given that the later is a well established method?

There isn't a problem with the damper parts other than the issues with the hub. Things looked good for a short time until the damper started slipping once again.

The original tapered part is clearly burnished from the damper sliding against it. This leads to the conclusion that the hub of the damper is eroded and probably accounts for part of the problem. How things got to this point is anyone's guess as the original (?) has the same problem. My manufacturing mind thinks the original part had tolerance issues but tough to say now. I inspected the bolt and see no reason why that would need to be replaced.

The last attempt before replacing everything is to shorten the tapered part to keep it from bottoming. This is currently being done at a machine shop. If this doesn't work then it will be necessary to buy a new damper, etc., under the hope that all new stuff will buy me another 65K miles. I checked with jaguarparts.com and they gave me a price of $1275 for the damper and about a week for delivery. This is not a standard stock item and the master parts warehouse is apparently in Atlanta.

 

Walt,

Try Jagbits and see what price they come up with. I recently been purchasing parts from them and they have been better than reasonable.

Link Jaguar Parts, New and Used Jaguar auto parts, XJ6, XJS, XJ8, XJ40, XK8, S-TYPE and X-TYPE Jaguar car parts

 

It's interesting that JPAM Jaguar parts has the damper for the 2005 XKR for $260. Something is not adding up. What year is your XKR?

 

Thats indeed odd, but interesting option actually, the 4.2 damper would imho even be a better option (not just because you get a 5% increase in supercharger speed), certainly at that low price. It has a better damping quality, as also the supercharger ring is now damped as well.

You need to use the front cover of a 4.2 engine for this to do, and you have to use a 6 rib fead belt, iirc the Gates K060935 will be a fit.

 

To repeat ...

You said your mechanic cut down the bolt head, therefore a new bolt is called for.

A new locking cone is a good idea because you have no idea of how much metal has been removed by wear nor if it was previously cut down by someone.

 

I have a MY 2000 XKR. The list price on the damper is in the $1600 range. The price I got yesterday ($1275) was less than what shows on the web site so am a little dubious on whether they had the correct part. That site is run by a BMW-Jaguar dealer in Detroit. I have used them a good bit and their pricing has always been better than what I see others reporting on this forum.

Regarding the 2005 damper I'm not sure I want to go there. I am pretty sure this will end up with a new one (or used from one of the tuner guys) as I am now certain that the damper hub is damaged. That will be resolved quickly as it is just about back together with a shortened tapered part. The damper did not self-center which confirms my pessimism. The mechanic is going to weak it to get on center or in-plane. I decided (with plenty of internal conflict) to ride this out knowing that it is likely a bad decision.

The tapered part (split ring collet according to the part label) is made from hardened steel. Maybe spring steel. The original one got really hot to the point of pitting. The damper hub is probably more of the same although I didn't get a look a that.

 

JPAM sells the 2000 damper for $1190. This is a Jag dealer in Las Vegas and I have dealt with them. You could also check Coventry West, they tend to run close to JPAM. I suggest looking at the crank end as well for wear. The collar was spinning on it as well. The way it works is as the center bolt pulls the damper towards the crank, the damper causes the collar to tighten down on the crank nose. If the crank has lost material, it may not tighten enough and spin. Just be sure to put some force on the damper and see that it is not loose.

 

So are you saying the assembly order is crank, collet, sealing ring, damper, bolt?