Real World Reviews: Jaguar XJ-S V12

70s cars 80s cars Reviews
In the latest Real World Review, tuning and engineering expert Ralph Hosier provides an engaging, entertaining and enlightening account of his Jaguar XJ-S V12.

I'm delighted to say that the latest Real World Review has been penned by none other than 'Sir' Ralph Hosier. Some say that Ralph's heart is shaped like a V12 engine and that he has engine oil pumping through his veins. All we know is that he's evo magazine's resident tuning and engineering expert and that he also appears in Practical Performance Car, Practical Classics and Classics Monthly. Having studied at Exeter College and Warwick University, Ralph went on to work for Ford at Dunton before setting up his own contract engineering company. He has since worked with the likes of Bentley, Jaguar and Land Rover, plus a number of racing teams. Over the years, Ralph has been involved with the pre-production of many high profile cars, so he would probably be a perfect chap to have a few drinks with! Put simply, Ralph knows his stuff and here he is waxing lyrical about his Jaguar XJ-S.

Over to you Ralph...
"The Jaguar XJ-S V12 is a legend. Actually it has several legends, not only for world beating refinement and performance, but also for record breaking service and running costs. The thought of driving about in a 30 year old Jaguar XJ-S V12 strikes fear into most petrolheads, the cost of fuel, the repair bills and the constant worry it will break down spectacularly in an inconvenient location or simply catch fire. So you might question my sanity for not only buying one of these superb motor cars for my everyday commuter but going one step beyond and taking it racing in the JEC XJS Championship. As you do. And to be fair you might have a point. But I have a distinct advantage when faced with such a magnitude of problems; I'm quite stupid once I get an idea in my head. 
The V12 in 5.3 form is a fantastic car with a 6500 rpm rev limit and over 300 bhp readily available, when it's working right, but the Achilles heal is the standard cooling system which is dire, oh and the electrics which are both complex and unreliable, oh and the bodywork which is made of rust. Apart from that they are fine.

Good cars go for north of £6,000, I can't afford a 'good' car so I am applying the Bangernomics principal and going for something that needs minimal work but cosmetically challenged and so a bit cheaper.

Some cars are born with problems and will never be reliable; some are so sweet they are practically blueprinted and that’s the one I was searching for. I found a 1987 model on eBay with 93,000 miles on it, which had the twin headlight kit that will come in useful later. It looked good on screen so I went to check it out. The owners were just quite simply splendid people. We were plied with cups of tea and talked about the history of the car; they had owned it for fifteen of its nineteen years. The car was kept in the garage under blankets.

Ralph Hosier's Jaguar XJ-S on PetrolBlog

Opening the bonnet revealed an industrial scrap compactor, it was as though someone had mistaken the cavernous engine bay for a skip and thrown in a dumper load of old pipes, hoses, wires and random thingys, then smoothed it all down with a rusty trowel.

Don’t get me wrong, it was all in good order, the fluids were topped up and clean, there were no leaks and the hoses were in good condition etc, but the photos in the manual simply do not convey the complexity in the engine bay, it really is full. All XJ-Ss are like that, for instance, to change the front spark plugs it is best to remove the air conditioning pump. I quietly shut the bonnet and turned away wondering what I was thinking of.

Ralph Hosier's Jaguar XJ-S engine bay

The rest of the car had a little surface rust - all cheap cars are rotten, so I planned for welding. The front subframe which holds the engine up and holds the suspension on rusts from the inside out, good second hand parts are over £250 and quite a big job to change, so getting a good one was quite important. The smaller cross member under the radiator also rots out but can easily be replaced with a strip of suitable metal and is not a deal breaker.

The front of the sills rots behind the ally splash guard, cunning design that, but is reasonably simple to repair. The back of the sills is a very complex construction, no, actually its an utterly bizarrely complex construction and includes the rear axle radius arm mount and is a sod to rebuild. Pulling up the rear seat base can show if this area is rotten, rain water leaks in from the quarter light seals and pool in the seat base/ inner sill area. Similarly the front foot wells suffer where water from leaking screen seals can pool and rot the floor. Many cars have been undersealed which is surprisingly unhelpful as the rot starts from the inside of the car and the underseal can trap it and hide it from inspection. Brilliant. But a quick fondle of the sills on this car showed them to be fairly sound. Note I say fairly, not entirely.

The car also had the standard sagging head lining feature and very old tyres but was basically in surprisingly good shape, it even had a new radiator, oil cooler, brake disks, front subframe, front cross member, rear calliper, battery and a centre exhaust. The engine was quiet from cold, pulled strongly and smoothly on the test drive, with no worrying noises. It gathered pace quite readily and handled corners competently with a polite bow from its very soft suspension. A magnificent if rather unresponsive drive.

Mechanically the cars are strong, but bushes, bearings and ball joints wear due to the considerable mass of this classic barge. The theme of 'really complicated' continues in the gearbox mounting; a cunning and complex unit made from a spring, foam damper, sliding pin and several brackets flying in close formation and are renown for letting the gearbox rattle against the body when worn, which this did. The steering is amazingly isolated, great for a gentle Sunday cruse but can be sharpened up nicely with polyurethane bushes.

Ralph Hosier's Jaguar XJ-S bonnet

I decided to go for it so I put in my maximum bid and did not look at it again until after the auction, not the best way to win an eBay auction but I felt that fate would decide what path my life should take at this point. Luckily, at least I think it was lucky, I won it for my limit of £1500 and so the next week I had my first XJ-S. It was just after I had handed over the money and received the keys that I suddenly realised what I had done, in an instant it had gone from an idea to reality, just shy of two tons of reality.

Driving it over 100 miles to get home highlighted a few surprises, firstly the engine was so quiet round town I actually couldn't hear it. I mean I couldn't hear it at all, loudest thing in the car was the clock. But as speed builds wind noise increases due to the 70s roof gutters and other air traps, but even at 140 mph (private test track) there is no need to raise your voice to chat to the passenger.

Obviously a cheap car is going to have its wayward tendencies and this old barge felt very vague round the twisty back roads, and under-steered dramatically when being pushed hard, in a sort of 'hello hedge' sort of way.

But on a mixed bag of driving astonishingly it averaged 25 mpg. No, really it did. Not quite the horrific gas guzzler I had expected. By comparison I used to run a 4.2 XJ6 of '84 vintage which struggled to reach 17 mpg when driven gently. There are many technical reasons for this miracle which I won't go into now, suffice to say the Jaguar V12 remains one of my all time favourite engines, it really is damn good.

Owning such a magnificent chariot changed me in ways I hadn't imagined; I actually cleaned it. Now I should at this point explain that I never clean my cars, I maintain them, look after them, but don't really give a stuff about how they look, so this was a remarkable development. But I have to say it's lustrous black paint looked simply stunning after a good wash and wax. I actually felt proud to own it, very odd, not like me at all.

Ralph Hosier's Jaguar XJ-S on PetrolBlog

And I absolutely loved driving it, I took every opportunity to take it for a spin, the cream leather seats proving the most comfortable I have ever sat in. I even managed to get 4 large adults in the old Jag on one notable occasion, although the rear passengers did end up with numb legs.

Ralph Hosier's Jaguar XJ-S interior

As you might expect from an old banger performance was a little down, a 0-60 test came in at about 9 seconds rather than the 7.5 in the book. Nothing that a thorough service wouldn't fix. But interestingly the acceleration seemed to just keep on coming as the speed rose, even well above 100 mph the pace gathered relentlessly.

Having spent a week driving round in splendid V12 opulence, it seemed rather a shame to tear it asunder but I wanted to reduce its weight by at least 10% and scratch that racing itch.

The first stage was a fairly simple set of modifications that most people could do, this leaves the car in a perfectly usable state for road use and I continued using it for general transport duties.

Basically I took the multi-layered sound deadening out from under the carpets, fitting performance brake pads, brake fluid, adjustable front dampers and removing the massive air con system. I removed one set of exhaust silencers and fitted a straight through tube, this lets the V12 growl out without making my ears bleed. Inside I fitted a race seat, race steering wheel to replace the huge and yet spindly standard item. A freshly shaved set of performance road tyres transformed the grip levels. The engine was pampered with a very thorough service, as was the diff, gearbox and a few suspension ball joints replaced to be on the safe side.

Then I located the inevitable rust. There was a bodged repair to the inner wheel arch and the rear seat pan was a huge hidden rust lake. Amazing it had passed an MOT only a few months before. Luckily I like welding.

With only two days to go before the Mallory Park track day I had booked for practice, one of the rear calliper bleed nipples sheared off. The inboard callipers are an absolute sod to get at and the task of removing it, drilling it out and refitting it, occupied the best part of day. One of the many low points in this project that illustrated just how much perseverance is needed to make a project like this work.

With all the prep work done it's time to tune the driver, so its off to the JEC track day at Mallory, for a bit of practice. It’s a lovely circuit, quite short and has a lake in the middle that James Hunt nearly drowned in.

Ralph Hosier's Jaguar XJ-S at Mallory Park

Once the tyres had gone through their first heat cycle, needed to get them up to full grip, it was time to push harder. The car gripped and then gripped some more, pushing me firmly into the side of my seat round the large corner, with the lake as run off. This is the first time I have heard the throaty exhaust at full tilt, and it was utterly spine tingling.

The next session out I took a passenger who looked a bit apprehensive, but once we got into the swing of it he looked a lot worse. That may have had something to do with me saying “look, that’s 110 mph!” just before breaking very hard for the hairpin and having some degree of sideways progress. We came in after that.

What a fantastic car, whether standard or modified it is a remarkable experience. But when it comes to fixing it the faint hearted should not apply."

You can follow Ralph on twitter or via his website or even his blog.