I bought an unbelievably mint 1998 XK8 with 63k on it and a major caveat...the Interior is immaculate. The body is perfect. The engine is...not so good.

It wouldn't run so I popped the valve covers off last night and found this....

Not only is the chain broken, but the busted pieces of tensioner were sucked in between the cam gear and the chain and subsequently wedged against the head effectively seizing the cam.

fantastic...

The bottom end seems mint, and only the passenger side secondary timing chain broke so I'm in need some help here,

1.) I'm putting together a worst case scenario cost analysis.

So assuming that all the valves are crushed how much do the valves cost, and where can I get them (hopefully aside from the dealer) but if it is dealer only does anyone know the cost of parts? As for the headbolts, are they one time use "stretch" bolts? Generally when I pull heads I ditch the old bolts anyway I'm just curious.

I see ebay kits to the tune of 700 bucks. These include what appears to be all the parts I need including all gaskets and seals, the third gen tensioners all 4 timing chains and the necessary bolts. I'm a bit leery of ebay parts but given the track record of the Jag parts, I don't imagine that they can be that much worse. http://cgi.ebay.com/ebaymotors/JAGUA...Q5fAccessories

Since I'm going to be in there I'm going to go ahead and replace the water pump, as well as the thermostat. Furthermore I'm considering changing the water housing. Is there a non plastic equivalent or perhaps an upgraded one?

What else should I be replacing while I'm in there? Perhaps the oil pump? I have no interest in pulling the motor apart again in a year because I should have done something else the first time.

As for my mechanicle experience I have a pretty good amount of mechanicle experience however I am NOT a mechanic. I have built several 3000gt's from the ground up so I''m used to over engineerd complicated vehichles. I also know my way around an F-body, late model mustangs, and Vipers. Ive spun bearings, and blown turbos, I have rebuilt everything myself (aside from the machining of course). However I have never rebuilt a head with variable valve timing, but I imagine it cant any more difficult than anythign else I have ever done. Any advice on anything regarding the Jag is greatly appreciated. I just thought I would let you know where I'm coming from.

2.) I'd like to upgrade where possible while it's apart. I think another 45 - 60 horse or so would be a pleasent kick in the buns. I'm debating about some oversize valves and a port and polish on the heads, I'm just not sure it will be worth the $$$$ for what will probably amount to just a 25 or so horsepower increase. On the otherhand I have no experience with the jag motor so I dunno what kind of increase I'm looking really looking at, my 25 number is just a guess.

I want nothing to do with forced induction on the Jag. I have been screwing with the tuning on forced induction cars for last ten years and I'm just over dealing with maps and constant tuning. What a headache!

Obviously at this point gutting the cats and freeing up the intake would net a few more horse and may be worth the time and effort.

Thoughts will be appreciated! Thanks for the HELP!

 

If you are going to go this far into the engine I would want to know the interiority of the Nikasil engine block. A dam shame to make all the repairs and a have problems with no compression due to washed cylinder walls and have to do it all again.

 

You may get lucky. It may be that the valves are not bent and did not damage the pistons. I'd put on new tensioners and chains (secondary only). Like Gus says, check on the cylinder liners first. In this state I think you'd have to do a leak down test, but I would first fix the chain and tensioners and try to start up before going into the cylinder heads proper. Then you could also do a compression test.

If you are not lucky, then I'd find a new engine because if the valves are involved, most likely the pistons are shot too.

There is not much in the way of upgrading this engine, so forget about bigger valves, etc. If you want to go uptown, get yourself a supercharged 4.0 and drop in the complete unit. The R engines are nothing like what you have been used to. I have a 300zx Twin turbo and know what you are talking about. The supercharged jags are trouble free and reliable.

 

I can't seem to find the "master link" secondary timing chains, the ones that allow you to change just the secondary chains without primary chain removal. I would happily give this a try if I could find the chains. Otherwise it seems foolhardy to take everything apart and reuse the already cracked and broken timing gear to try and test it. Thats alot of time and risk.

As for finding and installing the supercharged unit, I would require either a fuel controller or an ECU and wiring harness out of an XKR correct? So I would either need the complete car, or fuel management to make it work.I suppose I could probably get just the XKR ECU, and get to digging through the wiring diagrams and re-pinning the old harness to the XKR ECU.

As for "no upgrades", how much of this engine is shared with the lincoln 3.9? and is any of it related to the ford modular v8's? I'm wonderingif maybe there isn't a swappable cam or something...I suppose I could have the cam welded, and re profile the cam for slightly more lift and duration. Though again I don't think that's very cost effective for the moderate gains I'm lookign for.

And thank you for taking the time to reply to my thread

As for the 300ZX, all I have to say about that is, NO THANK YOU! If I never see another one of those It will be too soon... Just like the 3000gt most minor work on them is an exercise in saintlike patience.

I think the lower end is probably fine, there wasn't a drop of oil in the intake, the oil was nice and clean with no shavings, and even if there was piston valve contact I doubt it hurt the pistons too much. I have seen several 3000gt's with some valve marks on the pistons and they ran just fine for years after the valves were replaced. In fact one of them was running lean on those scored pistons and I figured it would create a hot spot or a weak spot and either fracture the piston or burn a hole right through it. I was wrong it ran fine on 14lbs of lean boost and never had an issue. On the other hand I have been wrong before.

I'll get on that leakdown test as soon as time allows. Anyone know what respectable #'s are for these engines? I have read that they have loose ring tolerance is this true?

 

And a very merry Xmas to me! I pulled the exhaust cam off, ran a compression check on the pass side (with the broken chain) and found.... 140-150 compression across the board

So, no crushed valves for me! Anyone happen to know where I can get the secondary timing chains that have the master link in them so I don't have to remove the main timing chain? on the other hand maybe I should just change everything....

 

Sounds great! Go to http://www.motorcarsltd.com/ Ask for Ken in the parts department. He is also a member of this forum.

 

I read an interesting post on changing the secondary chains by unbolting the cams, tilting the cams up and slipping the new chain on from the rear. Don't know why that wouldn't work and is a heck of a lot easier than pulling the front of the engine off.

Doing that, I would make sure that the crank locking pin was in place and that cam locking tools were used on both sides. The cam sprockets to cam connections are infinitely variable, Morris taper type. A couple degrees here would be noticeable.

The Lincoln LS '00-'03 parts are interchangeable with your engine, at least as far as the tensioners are concerned and are about half the price as parts sourced from Jaguar suppliers.

There is an aluminum thermostat tower that I would recommend. The OEM plastic ones sooner or later will leak.

Up grading the engine is an often discussed subject but little success has been reported on anything beyond a more open exhaust system. Bolting on the 'R' supercharger is not economically feasible.

Congratulations on what appears to be a great fine.

 

I would fear screwing up the VVT solonoid when removing the intake cam. Especially when there is an alternative....But I would appreciate the link so I can read it if you don't mind.

Are you suggesting that the tensioners from the Lincoln will work as well and cost considerably less? Because that would be fantastic. Would the thermostat housing also be available as a lincoln part or would this be an upgraded 3rd gen piece from jaguar?

Hey does anyone know what the torque specs are on the camshaft bolts?

And thanks for the tip on talking to Ken, whats his screename on here I'll shoot him a PM. Thanks again guys for the information it really is useful! and Merry Christmas!

PS. I just found all the service records for the car in the owners manual...this car has been dealer serviced since day 1 and is a one owner! WOW what an Xmas present to me!

 

As involved as you are getting I would suggest a membership to www.AllData.com

 

I was thinking I should pickup the factory service manual, I generally pick them up for cars I end up getting deeply involved in and for whatever reason I haven't really had good luck with all data. For whatever reason, they seem to be spotty on information. For instance they will have a great deal of information on car x while car y is missing something integral that makes me want to tear my hair out. However, it has been a number of years since I swore them off.

Have they improved in the last 7 years or so? If so how are they with the Jags? Spot on, mostly complete?

 

I would replace only the secondary chain and tensioners. The primaries are much less likely to go bad. I did the primaries on my '97 w/ 60K miles and they were almost perfect, while the secondary tensioners were already cracking off pieces into the oil pan.

There are a number of tech writeups floating around on the secondaries. With your experience you will find this project relatively simple.

http://www.jaguarforum.co.uk/viewtopic.php?t=11333

http://www.jagservice.net/jaguar_v8_...tensioners.htm

http://www.roadfly.com/jaguar/galler...36878,1;-54,3;

All Data is too expensive. Get a copy of the CD factory service manual for $10.

Try Ken@British for the parts, if not I get most of my stuff here: http://www.trademotion.com/partlocat...?siteid=214626

 

No you are right on the most part. It has improved but the way I deal with it is what I am unable to find on alldata I let them know that they fell short. Then I post on this forum and hope I get what I need and in most cases I do.

 

The factory service manual was a CD based system called JTIS. It is the basis for the AllData data base with enhancements.

No paper manual was available.

The JTIS is available for download free here:

https://www.jaguarforums.com/forum/general-tech-help-7/

All torque values are available there.

 

Tom,
I know that you along with many others use and like the JTIS Manual; however, it fell short on me several times and for that reason I use AllData. Also on AllData you can send a question for additional information. Just an FYI for others!

 

I think I probably asked this before but how is it that there is no source from which to get a decent hard copy service manual, even by some third party like Haynes or Helms? This is the first car I have ever owned where I have not been easily able to get such a document. I find the JTIS CD to be just somewhat better than useless.

Doug

 

JTIS took a l o n g time to get use to but then I stopped and read the help file on the file structure and how to effectively search and the CD functionality got much better. Must have had a hidden key linked to accessing the help file.

You're right, we are all programmed by our age to prefer a paper manual but that is not going to happen any more, ever again.

 

Sigh...I just got called "old" indirectly on a forum I've only been on for week.

 

Don't feel bad. Jaguar owners have to have a thick skin to survive.

 

Fixed.



Jaguar, turning everyday people into everyday mechanics.

I should trademark that.


So where can I get the timing tools on the cheap to finish this job?

 

If you are saying that you fixed the car, Kudos to you!