My mechanic is telling me that my '02 XJR has thrown timing belt and is offering 3 options:
-Junk it (donate to a charity)
-Replace timing chains (3) and valve job - $7000
-Install used engine w/61K miles on it - $6000

Car engine stopped suddenly after start in driveway; engine will turnover and can be kept running w/gas but makes no compression (i.e. can't drive it at all, even w/foot on gas).

Car was bought as pre-owned in '04 from a dealer (out of area) and has approx 110,000 miles on it.

Am located in Southern California.

Anyone have any exprience/advice that they could bring to bear on this?

Thanks much.

 

it's a timing chain issue...if a secondary chain has skipped 1 tooth because the tensioner has collapsed, the engine will run...poorly. If it has skipped 2 teeth....you need a valve job on the affected head and the engine won't run at all. Rarer on an 02, this issue is covered all over this board. If it runs, you haven't crunched the valves....but you must get it fixed pronto, (do not attempet to drive).

 

I just went through fixing my secondary timing chain tensioners. Mine skipped a tooth, but it would start, run and drive but very rough. Now that is is fixed and the timing is setup correctly it runs fine.

You mentioned making no compression. Did your mechanic run a compression check and told you a cylinder or two was making no compression? If so those valves are likely bent in those cylinders.

 

So far, two bent exhaust valves on the driver's side. Think the pass. side is ok.

Any thoughts on quotes I'm getting (approx. $7k for timing chain re-build and valve job)? The mechanic seems like a good guy but I've got nothing to guage his estimates against.

Consensus from other sources is not to put a used engine in if the existing one is fixable; likely will have the same problem down the road...

Thanks for your thoughts.

 

If your having someone else do the work you may be limited to a used engine or at least used heads. So if you were to find a used head that looked decent you could swap heads, install new timing chains and it should work. But you can never tell with used stuff. You could and maybe should look into a valve job if you were to get new head(s), but I don't know what that would run. I don't know if they are the same, but a nicasil (sp?) engine may yield some nice heads.

If your situation were mine and almost was I would be looking for a used head or head(s) and full timing chain setup. Since I now know what is involved first hand on the timing I feel that would be my best bet.

I know one thing is for sure, I would not pay 7k to fix anything on an '02 XJ, since it is almost as much as the car itself is worth.

Maybe a jag tech will chime in with some info on costs for your situation

 

if you have any technical knowledge do it your self... I just did.. have changed all timing stuff- tensioners, gaskets, chains... never did anything like that ( only bicykce chain )
it was first time, it's not so hard and if you manadge to do the timing you will manadge to take the heads aswell... take the head off, take it to the one who had done the valve stuff before ( it doesn't have to be jaguar mechanic ) buy al timing parts (i payed 600gb pounds on britishparts.co.uk) put everything in their places and there you have an angine that you dont have to worry about another 200,000km ( not counting electrical part and the nicasil) so total i have spent on the timing was 900 gb pounds...
it ook me two weeks spending 2 to 6 hours a day in the garage with cold bear included

 

There isn't much to speculate about, it's just a question of evaluating the facts.

If one of the exhaust camshafts is in fact out of phase, I'd assume this is an early '02 engine with the single row chain, and one of the secondary tensioners failed. Bent valves are easy to find, you will see a measurable increase in the valve clearance. You can also remove the exhaust camshaft on the affected side and perform a compression and/ or a leakdown test.

The fact that this failure occurred at idle means that it is unlikely the the cylinder head or any pistons were damaged: removing the head for inpection is the next necessary step. There is no valid reason to pull the other head in my opinion. The engine has 110 K on it, I would replace the bent valves if no other damage occurred and reassemble the engine with new timing components. Even for a supercharged engine, $7K is a little bit strong in my opinion. That's more like $4K in my book, which is alot cheaper than installing a low mileage engine.

 

I agree with with JTO, you can put in 2 new exhaust valves and lap them in. They will seal just fine, as the seats are probobly not damaged either. But I would replace at the minimum both upper/lower tensioners, blades and the upper chains...Its alittle bit more costly on a supercharged engine since the blower and intercoolers have to come off and its alot more work than a NA motor. Now if it were me. Ide pull both heads, port them, install 1mm larger Ferrea valves, springs and titanium retainers, smaller blower pulley. and extrude hone the exhaust manifolds, and add methanol injection....oh, and tune the whole shebang

 

Don't forget the wheelie casters. Is your track day in the test car still on?

 

Quick follow-up for those in the know...what's the liklihood of the other valve head/valves being damaged; mechanic just told me he found low compression on pass. side as well?

Thanks, everyone, for your thoughtful responses. I'm not a mechanic and don't have the space to do the work (garage is full) so I'm going to have to have someone do it.

 

At first blush, I'd say find another mechanic. If there are in fact bent valves, it's because one of the secondary timing chains broke. This has zero effect on the other bank of the engine. If the car was overheated, or it was running poorly and/ or flagging a check engine warning, then perhaps you do have a problem with both banks. This is a speculative discussion based on incomplete information which is being read through translation. Not a good way to diagnose an engine problem.

 

maybe Im supposed to go weds, but now have a court date that day (divorice issues) so Im gonna try to go thursday instead

 

Thanks to all who responded. No valve job, just timing chains and misc. other work. Appreciate the time/interest you all invest in this forum.