Hello everyone I am new here and have posted in the S Type forum recently. I was about to purchase an S Type but decided to pass at the last minute. Then yesterday a friend heard me speak of it and offered me his 90 XJS, which I love the body style, with 70K on the V12 motor.

I know some of you here hate Chevy's in the Jag body but I was thinking if I did decide to sell the motor which runs how easy would it be and would it sell for like $300? just curious I am trying to weight it all in the purchase decision. I am not really adverse to keeping the 12 but even though I am a DIYer I am a little worried about the motor.

Any advise would be much appreciated.

 

If it runs well you should have no problem selling it for $300. The problem will be finding a buyer. There isn't a large demand for used V12s.

Ideally, if circumstances permit, you'd advertise the motor for sale while it is still in the car so the prospective buyer can "hear it run".

Since you're a good DIYer you'll have no problem with the V12 engine itself. Just keep it cool and it'll last forever. However, there are a number of things *on* the engine that'll you'll probably need to address: fuel hoses, repair some crispy wiring, make sure the ignition system is in good shape, etc.

Cheers
DD

 

Thanks so really I should keep the motor in and just work on it over time since it is a second car/project? I know how rumors can be so untrue about car but I have always been scared of Jags even though I though they were sweet cars.

 

The rumors are not false but they are wayyyyy overblown and the facts distorted.

An older Jag WILL need TLC. Even under the best of circumstances they are not "drive it and forget it" cars. However, for most DIYer that's all part of the fun and these cars are worth the effort.

When you buy a used Jag you'll usually spend time and money catching up on repairs and services that the previous owners didn't do. Once you get everything up-to-snuff you can enjoy the car with just a Saturday of tinkering here and there to stay on top of things.

It's sad that so many of these cars are neglected.

I was nervous about buying a V12 as well. As it turned out the V12 engine was about the only part of the car that *didn't* need repairs :-).

Cheers
DD

 

OK so I purchased the car but the sucky part is that I did not take pictures. It is black with grey leather and over all in fair shape. The interior is better than I thought it would be though. The car turned over but did not start due to the fuel pump not working plus old fuel. Power accessories worked and it really did not have much in the way of rust.

Cool part is he gave me these green Jaguar binders that are factory service books seemingly from the dealership. It is about 5 of them and they are very thick......for sale anyone...lol. Anyway he stated that the car has never had any issues with the engine but rather with power steering leaking and going out but the car runs and drives. It has about 71K on the engine so i guess I will get to tinkering with it soon.

Quick question....he told me that the valves have to be adjusted yearly....this can not be true is it?

 

I am bumping the thread to see if someone will help me answer this question-

Quick question....he told me that the valves have to be adjusted yearly....this can not be true is it?

 

My dad has never had his valves adjusted since he bought his xjs in '92. I haven't either in my '87. Whether or not that is the right thing to do I doubt it but both of our cars haven't suffered any ill effects. By the way.. I might as well add that my dad's car is on it's 3rd V12. (1st seazed up when he got it, 2nd one burned up, 3rd one just right :-))He always wanted to keep it original Haha. My car, aside from an overheating issue that was remedied has been as reliable as any other car you might find. (knock on wood) The engines were built by hand so there were a ton of quality control issues. You might get a rocket, or you might get a lawn mower. IMHO I would keep the engine in it and if you wanted to swap, might as well wait until something goes wrong with the the V12?

Lou

 

Yea I really need to make a call and stick with it. I had priced the conversion kit and was going to just move with it but I guess I will try to work on the current set up and just see how it goes first. I really appreciate the help because the car really is foreign to me.

 

If you were closer to me I say yeah, change the engine, just so I could be selfish and buy yours as a spare to tinker with. But in all seriousness, a Jag with a Chevy has never appealed to me and definitely does not hold the same value. I have had several high powered big-block cars and enjoyed them for what they were. I would not trade the v12 for a v8. Personally I have found that every time I work on this engine it just gets better and better. I had to catch up on neglected maintenance and have done basically nothing to it since. I just plan on doing the preventative maintenance that it needs at this point. And bty it has been 100% reliable since. It has basically been driven daily. I haven't had a car respond like that in a long time. As for the valves, they should never need any adjustment, unless there is a problem. They are cam on buckets, so the only way to adjust them is to remove the cams and change the shims under them. Somebody was getting soaked by being told they need to be adjusted every year. Some Jag mechanic looking for an easy buck without having to do anything to the car.I'm sure he just pulled it into the shop and parked it in an empty bay and told the customer to come back in 2 days! Keep the 12, it runs and feels great and gets better gas mileage than you'll ever get out of a v8, even if it has overdrive. Of course that's just my opinion.

 

Ok your making me feel better and better I will just work with what I have then. If I were to spend 1K on some DIY self work what should I start with. On thing I know is the power steering system and fuel hoses at the top of the motor. If there is anything to really consider out side of regular stuff please advice.

 

if you're going to be in there, you might want to think about changing the fuel injection harness. They were poorly designed by the prince of darkness himself.

 

I'll always defend old Lucas :-)

Having dissected (and made up) a few FI harnesses I don't really think there's a fault with the harness design. Seems about the same as most other FI harnesses of the era....although the redundancy of wires always made me giggle a little.

However, why Jaguar decided to bury the darn thing in the depths of the "Vee" where it'll get so badly cooked is a mystery to me. Were it not for that I don;t think we'd see any unusual failure rates.

I route new ones above the injectors, along the fuel rail, FWIW

I recall a couple harnesses labeled "Rists"...which I thought was a different supplier. It turns out that "Lucas" was actually "Lucas Rists". Whether or not that was just an "on paper" legality ...with separate manufacturing facilities or methods....I don't know.

If you buy true OEM jag plug wires are are (or at least used to be) "Rists".

Just some useless trivia :-)

Cheers
DD

 

Doug, I'm doing the same thing with the harnesses I'm building by making them longer so they can attach to the fuel rail and out of death valley. But I have no love of Lucas...lol

 

Interesting do I do about getting this harness new from dealer or is it available on line.

 

There are some on-line suppliers ...just Google it. Expect to pay $600+ for a new harness.... which is why many of us make our own. Just basic skills required to make one.

Cheers
DD

 

Cool thanks again for the help I will update once I get started this weekend.

 

Here is *a harness. Not stock but an upgrade.. If interested.

XJS V12 EFI Wiring Harness

 

Rayjht, I inquired about that same harness from "the driven man" last year and was told they had no more in stock and wasn't given any idea if they were going to have any more made or not.Maybe they have some now. As far as what to check on your engine. First, if you haven't already, download Kirby Palms e-book. If you suspect that the car has been neglected at all, I would start with the dizzy as the Brits call it, or better known to us as the distributer. When we got ours it seemed to run just fine. It did run a little hot, right at the mid-way point but not what I would call overheating. I pulled the dizzy to find the mechanical advance frozen, and the vacuum advance in-operable. No advance at all!Also the plugs were wrongly gapped. After fixing the dizzy, replacing plugs with new properly gapped ones, and getting new high-performance wires, the difference was amazing and it ran cooler. Right where it should about 1/4" below the halfway mark. More power, cooler running, it's amazing what actually having some advance will do.Next I went through the throttle synchronizing procedure and wow, what a response difference off idle. Of course I replaced worn bushings, faulty vacuum lines and so on. Every step I did made a difference. It just got better and better. Believe me, you won't be disappointed!

 

I'm building two fuel injection harnesses right now, one for myself and another for one of the members here. Assuming he is happy with the finished product, I don't mind making another if anyone is interested.

 

How much will be you charging for it?
The guy I am buying the car from is the second owner and when he purchased the car he put some money in it but then let it sit for a long time so yea I think the hoses and such will have to be replaced. The good part is he gave me these: