1985 vs 1990 XJ-S coupe purchase/performance differences?

Can anyone give me some advice on a purchase of a 1985 vs 1990 XJ-S?
Is there any difference in performance from the HE version in 1985 compared to the 1990 V12 model year?
Cars I am considering are both under 20,000 miles cars. 1990 from a collection/estate, hardly used but always serviced. Both essentially one owner cars from new.
Have read of the Marelli issues, but with low mile car in 1990 believe I can have it serviced to prevent issues.
Will be in a collection, not driven too much with my 1965 E type coupe and 1960 Mk2.
Thanks for any advice.

I don’t own neither Lucas nor Marelli 5.3L V12, but from what I’ve read on this forum, there is no HP gain/loss (if this is what you mean by performance). Both will have the 2.88 differential and the TH400 transmission.

Some power gains are to be had with the Jaguar 6.0L V12, which I do own. The biggest difference (aside from the slightly larger displacement) is the 3.54 rear and the 4-speed electronic 4L80e transmission.

Whether you go with the 85 or 90 car, with only 20,000 miles on each, be prepared to do lots of “catch-up” maintenance. It is the years since rolling the assembly line, not the miles that you’ll have to go against.

Good luck!

Is the HE engine in1985 and the 1990 the same specs/compression, etc., or what is the difference?
Just curious if HP is lower in 1990 and any change in performance, 0-60, etc.?

Again, textbook knowledge on the subject only. The 1981-1988 5.3L V12 had Lucas Ignition.
The Mid-1989 till 1992 5.3L V12 had Marelli. Based on the Jaguar data, engines are same specs:

1990 will have different brakes and some other updates, but I do not think the performance (US market) will be any different

Same rated horsepower. Same compression; USA cars and all Marelli cars had the lower 11.5 compression ratio.

There are a slew of differences between and 1985 car and a 1990 but the over-the-road performance should be essentially the same.

As I recall the transmission was tweaked a bit in 1989 to give higher RPM upshifts at WOT. That might account for a slight difference.


I went through the same dilemma last year when I was looking for an XJS. Here is why I decided on my 88 XJS instead of an 89-91. (and I did not want a Facelift, I prefer the look of the pre-facelift, so 92-95 was out of the question)

  1. IGNITION: I preferred a Lucas ignition over a Marelli ignition. I know the Marelli issues are well documented and if you keep up on it, you won’t have a fire. But I just didn’t want to deal with it, and I noticed decent caps and rotors were harder to find for the Marelli compared to the Lucas. The shortcomings of the Lucas is that the centrifugal advance system will seize, but after reading Kirby’s book, I disassembled it and used synthetic oil. It sounds like once you do that and maintain the oiling, it won’t seize. Also, I like that I can adjust the timing on a Lucas ignition.
  2. BRAKES: The Teves II ABS brake system, found on 89-91, is notorious for problems, and expensive to fix. Kirby actually suggests to ditch it. I am very happy with my simple non-ABS brake system. I recently replaced the master cylinder - was only $150 and took 30 minutes! (not including brake bleeding) (NOTE: You can retrofit an older non-ABS system, but i don’t know how much work it is)
  3. AIR BAGS: Now, you’d think I’d want an air bag. But I liked that my 88 didn’t, so I could easily replace the steering wheel with a smaller wooden one. IMO the OEM steering wheel on these cars looks like it’s from a Pontiac! And I needed the extra leg room with a smaller steering wheel.
  4. SEAT BELTS: Now, this is a PROBLEM with buying my 88. It had the passive seat belt system, which is horrible. I think it’s only on 88-89? But I’m in the middle of removing it and putting in the 3pt system from an 85-86, which is a lot of work, but doable.
  5. QUALITY - So, I’ve read sources that say if you want an XJS, assembly quality improved every year, right up to 95. So if you want an HE between 81-88, the newer the better. Another reason I only looked for XJS’s from 86-88.

Otherwise, I think these cars are identical in performance and looks.

Good luck on your search!

1 Like

A slew of small changes came with the 1988 USA MY cars.

If you’re lucky you can find one without the motorized belts. My '88, which was a very early build, didn’t have them… even though the literature said it should.

For the USA market, 1988 MY began with VIN 139051 but, near as I can tell, the motorized belts actually came along at about 141xxx. I’ve always wondered about the exact break point but haven’t been able to pinpoint it.


My Vin is 1410xx and has the passive belts. But I assume only US cars had it?

What type of paint is on a 1990 XJ-S? Single stage, or clearcoat?Or?

Relative to the seat belt question, my 88 xjsc has the motorized belts at vin 140160.
They surprise people who don’t remember what they were like…

1 Like

What difference does it make…if you’re just gonna have it in a collection. …hmmmmmm

Thanks for your help. I drive them too, but have more than one car and just trying to be educated on the XJ-S.

If you want to be educated about the XJ-S/XJS here are some of the books that I purchased and have in my personal Jaguar library.

  1. “The Jaguar XJ-S Essential Buyers Guide” by Peter Crespin.

  2. “XJ-S The Complete Story” by Graham Robson.

  3. “Jaguar XJ-S The Full Story of Jaguar’s Grand Tourer” by Brian Long.

  4. “Jaguar XJS Gold Portfolio 1975-1988” compiled and published by Brooklands Books.

I have no professional relationship with any of these authors. However, Peter Crespin is a personal friend and I have provided him with pictures of some of our Jaguars, including our 1990 XJ-S convertible, some of which he has used in his books. Peter did attribute those pictures to me in his books, but I am not compensated in any way for their use other than having those “bragging rights”. :wink:


I have two and have other two on order.
Thank you.