Well, one year ago this month, I bought my current XJS. Have put untold hours in it, getting it running great, working great. New top, brakes. Interior work. Details like new switches, power window motors disassembled, cleaned, greased. Reworked the power top pump, lines. Electrical grimlens brought under control. Had a wonderful day at my first all British event yesterday. All was well. Car seemed to be finally rewarding me with enjoyment. Parked it for a couple of hours, decided to go for a drive. Then the noise...the dreaded dropped valve noise. I know it well, as it happened in my former Jag. A 71 V12 E type. I am sick. A big job for little reward in the XJS.
My question now, as I sit here and look at my options, is to find another engine, prep it, and swap them out. I found a 6.0 liter not too far away. Seems cheap enough. The numbers matching thing isn't so important to me, as having a better power plant. Is putting a 6.0 in, using the 89 injection components a good idea? Maybe even use a 6.0 mixed with early pistons, flat heads, and injection from my car? So many questions.....

 

Sorry to hear this. I know exactly how disheartening that can be. Hey, at least it didn't burn to the ground. From what I understand (I am NOT a mechanic), the most efficient method would be to find a wrecked, but complete 6.0 and pull the entire drivetrain (engine, transmission, accessories, associated computers and sensors). Pop them in your 89. Wrecks go for little money.

Sounds like you've put a lot of work into your car and it would be a shame to lump it or let it go. I happen to think the 89 with Recaro seats and sports (non-airbag) steering wheel is the pinnacle of XJS design. Later models with the fussier seat pattern, large airbag, LCD trip computer, and non-barrel gauges just don't speak to me.

I say keep your baby and transplant that 6.0 and 4 speed transmission. You'll probably fall in love all over again.

Good luck!

[edit]

and if you go that route, PLEASE document it here - it's something I've always had in the back of my mind. The idea of the tidied up 6.0 engine compartment with the extra power and modern transmission really appeals to me.

 

This may sound weird but: how exactly does a dropped valve seat sound in the V12? I'm yet to (hopefully never!) experience it... Not that I am chucking money into this car outside and it has exactly that...!

 

It sounds like excessive valve clearance. Very subtle, but its there. The design of a overhead cam engine, causes it to lose valve clearance as the seat wears. Its a great design I think, except for this failure. I want to do a compression check, but I don't dare, as I know without tearing it down, that this is what it is.
As far as lumping it, I would let that be somebody else. I used to want to do that....but as I've gotten older, the smoothness of the V12, the allure of owning a V12, well......lets just say its a calling sort of.
I put a 5 speed in my E, and felt it was kinda useless. The 4 speed worked just as well. I do have thoughts of a 5 speed in this car though. With a 2:88 rear gear, a lower 1st gear ratio would put a little "umph" in it. But man...just the thought of the work makes me cringe.
I have read a good bit about converting the early engines to EFI, and getting really great results. Due to the age of the car, and that SC doesn't test emissions (yet), I do wonder about going to a flat head on my car. Especially since I have a set of the really really really rare group 44 heads sitting around collecting dust. I can't imagine what it would cost to build them though. Add that to the cost of all new liners and pistons, and well, you know....

Anyway, thoughts and ideas appreciated, as I am in the mourning/thinking/planning thought process right now. Have a couple of extra 5 speeds.....

 

i like the idea of a 6.0L with an after market ECU, and a 5 speed!

and good cooling system(aluminum radiator), elec fans, with effective air flow out of hood(vents).

as an after thought maybe in future, a rear gear ratio change 3.54 or there about.

i'm thinking it would be a bad a$s car.

 

Shouldn't be too terribly hard to find a decent used 5.3 and simply swap motors. No mods, no upgrades.....just remove one and install the other. A couple weekends oughta do it. Maybe one weekend if you have a good helper.

Shouldn't cost much for a good used 5.3. Heck, some people can't even give 'em away. Put the word out that you're looking. Heck, I was given...as in free, no cost, no money....the absolute sweetest running Jag V12 you've ever heard. And it was wrapped up in a complete (but rough) Ser III sedan.

Cheers
DD

 

Free is good.....where in the world would I put the word out to find something like a inexpensive 5.3?

 

Where?

This forum, other Jag forums, all the usual Jag parts vendors, Craigslist, JCNA Webpage.

Cheers
DD

 

I am still in a semi state of disbelief over this. My 71 V12, I had wound it up to about 7K, and when I let off the throttle, I could hear the ticking. On this car, it literally dropped a valve seat not running. Of course, I did have a irratic idle when it got to normal operating temp, (occasionally). That problem seemed to be going away the more I drove it, like injector not working correctly when hot. Very light miss. On my E, I bought some coolant flush from a company that all but guaranteed the heads to come off with relative ease, if I followed their instructions. I did, and the heads came off just as they had said. Much much different from the other V12 I rebuilt. (79 model if I recall). Anyway, I'm not really fearful of taking the heads off of this car, doing a valve job, but as those of you who've been there done that, its almost as easy to just pull the engine as it is to do a valve job with the engine in the car. Decisions, decissions. Maybe I'm trying to talk myself into making the car a little fun in the process.....

 

Oh, you must be gutted! How absolutely sucky!
I'm So sorry to see this.
(';')

 

does the dropped valve seat of a 5.3 v12 sound as terrible as the dropped seats of the four cylinder fords?

 

Check out the YouTube video on the V12 dropped valve seat. The bad thing about our Jag V12s, is that is just sounds like excessive valve clearance. Like you could drive it from now on like that....

 

Gene:


Oh, say it ain't so! I feel for you, man. What a path you've been on.


Hang in there, and don't give in! A 6L would be the ticket, sure enough.


I just put a 3.54 in my car, and even though I have the wide ratio Tremec (3.27 first) 5-speed, it's really something else. Pulls nice and strong even in 5th, and it never was able to do that with the 2.88. Actually, it pulls like a monster everywhere, pick your gear.


If you do go 5 or 6 speed, get a close ratio box, and put a 3.54 in there! Way more fun than you should be allowed!


Wow, I just can't believe your luck on this car.


-Mike

 

It really is a test I guess. I read your post Mike, with great envy I have to say. Would love to do a 6 liter, but seems a little more rare. The guy that has/had the 6 liter for sale in the classifieds has it sold... Seems the easiest thing at this point, is to get a set of heads, condition them, and then dive in. This car has no smoke, runs good (finally did), and then this... wadda ya do?

 

Sorry to hear about this. Time for a V8 swap! Just kidding- already saw your thoughts on this.

I have a silly question that probably has an equally silly answer: why can't you take the head off, get the head repaired by a machine shop, and put it back on? I've had the heads off on my XJ6 V8 swap more than once with very little fanfare. The worst part was draining the coolant- what a mess!

 

At the moment, thats what I would like to do. The thing is, I have torn down 3 Jag engines on a stand, and that isn't a cake walk so to speak. I know guys do it all the time, but removing the heads from the engine, in the car, seems almost overwhelming. What I am really trying to do right now, is find another engine (whice I think I have), and get the heads from it prepped, and then tackle it. I don't know about you guys, but finding a shop locally that takes in Jaguar heads isn't a easy thing to do. Much less ask them to do it in the same time frame that a set of small block chevy heads would be done. I'll know more after this weekend, as I may be going to get a engine...

 

Where are you located?

 

big difference between SBC heads and Jag V12 heads.

was a time when both SBC heads redone were $75.bucks a set, while set of V12 heads were around $500-600 set.

that has got to say something about labor, not counting materials used!

 

I'm in Greenville SC.