The XJ40 ushered in a new era, replacing the XJ6 that was in production for nearly 20 years
‘Really good cars are getting rare, so buying on condition rather than spec is definitely advisable’
Classic Jaguar saloons have always been terrific value, but anything built before the arrival of the XJ40 in 1986 is now becoming very collectable and less affordable as a result. So if you’re looking for a luxurious family classic, look no further than the elegant saloon that saved Jaguar.
The XJ40 was launched in the UK in 1986 and was available from the outset with a choice of straight-six engines: a 165bhp 2.9 OHC; and a 221bhp 3.6 DOHC straight, both derivatives of the AJ6 slant-six unit. The bigger engine was superseded in 1989 by a 235bhp 4.0-litre unit then in 1990 the 2.9-litre was replaced by a 200bhp 3.2-litre engine. We’re disregarding the 6.0-litre V12 here because you’re unlikely to find one, and some of the modifications mentioned here won’t be necessary.
All XJ40s are comfortable but some are more sporting and better appointed than others. Really good cars are getting rare, so buying on condition rather than spec is definitely advisable.
The entry-level 2.9-litre engine is probably best avoided because it has to work so hard, but it’s not difficult to swap it for something bigger. However, you’ll probably need to change the differential and front springs to suit and engine swaps can lead to issues with the DVLA. Starting with a bigger-engined car will always be less hassle.
As well as the mods below there are lots of cosmetic tweaks available for the XJ40, including body kits and additional chrome trim highlights.
But the ultimate XJ40 upgrade entails transplanting the running gear from an X300 XJR into a standard car. It’s a big job, but as long as you’ve got a suitable X300 donor car it’s more straightforward than you might think, because the X300 and XJ40 have a shared crossmember and the brakes fit straight on, too.
THE HIGHLIGHTS £60+ Some XJ40s got oblong headlamps, others four round lights. Neither is better than the other but they really change the car’s appearance. It’s an easy swap – even the dedicated bulb failure modules just slot straight in. FISHING FOR CHIPS £245 Each distinct XJ40 engine ECU leaves room for improvement. AJ6 Engineering offers modified venturis and ECU reprogramming to increase power by 15 per cent; a redesigned inlet manifold can boost this to 30bhp. BRAKE FORCE £271 Looking for stronger anchors? The easiest option is to buy a set of EBC discs and pads direct from www.ebcbrakeshop. co.uk. There are many options but the costliest kits cost £224 for the front and £170 for the rear. BREATHE EASIER £60 One of the easiest and cheapest ways to liberate more power is to replace the average standard air filter with a freer-flowing one from the likes of K&N or Pipercross; all engines respond well to one of these simple conversions. WHEELY GOOD £200+ Some XJ40s came with steel wheels and early alloys were metric, so later imperial wheels are popular. You can’t fit Series 3 or XJ-S wheels because the offsets are different but some X300 and XK8 wheels do fit the XJ40. SUSPEND DISBELIEF £300 Some XJ40s came with self-levelling rear suspension, which can be hideously unreliable and costs well over £1000 to fix when it goes wrong. Converting to a standard spring/damper set-up is a good idea. EXHAUSTING £695-£1225 Standard exhausts focus on refinement rather aural appeal and aren’t not as efficient as they could be. AJ6 Engineering’s extractor system and tubular manifold can boost midrange torque by as much as 12 per cent.