Classic Jaguar V12 Field Report
Jaguar Built Twelve Cylinders of Perfection. Then They Hid Four Nuts Where No Spanner Made Can Reach Them.
June 2026 · 9 min read
Nine years of this. I do my own work, because round here the man who could do it for me retired before I bought the car.
There is a job on this car that the workshop manual treats as routine and that has made grown men sell the finest engine this country ever built. It is getting at the inner exhaust manifold nuts on the V12. The nuts cost pennies. The reason men give up is not the nuts. It is that you can see them, you can touch them with two fingers, and you cannot get a spanner of any shape known to man square onto them.
I am not a mechanic and I am not selling anything. I am a retired quantity surveyor who spent forty years measuring other people's work, and for the last nine I have run a 1989 XJS V12 out of a single garage in Shropshire. I do my own servicing, partly because I like it, and mostly because the last proper Jaguar man in this county retired years ago, and what is left will quote you four figures with much sucking of teeth.
I am writing this for every owner who has knelt over that vast bonnet, looked down past the cam covers into that forest of pipes and rails, and felt the particular quiet anger of a capable man beaten by access. Because an old Browns Lane fitter named Den put the answer in my hand at a club night, and he told me to pass it on.
The part of the brochure they never wrote
Everyone tells you the same two things about the 5.3 V12. That it is turbine smooth, which is true. And that it is fiendishly complicated, which is not. It is a simple, strong engine. What it actually is, is BURIED. Jaguar drew that engine on a bench at Browns Lane where every nut sat out in the open, and then they lowered it into an engine bay with half an inch to spare on either side and routed the steering, the heater pipes and the exhaust around it like ivy.
The inner manifold and downpipe nuts ended up down between the block and the chassis rail, just above the starter. From above, your arm does not reach. From below, you are working blind past the steering. The two outer nuts on each side come off easily enough, which is the cruel part, because it convinces you the job is on. Then you meet the inner ones. Men on the owners' forums have dropped the entire steering rack to free one nut. One chap, mid restoration, gave up and pulled the whole engine. For four nuts.
Everything in my toolbox had a go. Here is how each one did.
- Standard ratchet. There is no swing between the manifold and the rail. Two clicks and it stopped dead.
- Flex-head ratchet. Reached in beautifully, then folded at the joint the moment I leaned on it. Knuckles into the manifold, which was not cold.
- Swivel socket on a long extension. Walked off-axis under load and started rounding the nut. A rounding nut on a forty year old stud is how a bad afternoon becomes a bad month.
- Working by feel, one arm down the back, cheek pressed on the cam cover. Tedious, bloody, and the nut never moved.
- The specialist. A four figure estimate, a long wait, and that slow sucking of air through the teeth that every classic owner in Britain knows by heart.
What the access actually costs a man over here
Put the real numbers on the table. A fellow on the owners' forum was quoted nearly four hundred and seventy pounds for a light service on his XJS, and over eight hundred and eighty for the full one, and that is before anyone touches a seized fastener. Dealer hourly rates are politely described as brutal, if they will even accept a thirty five year old car, and many will not. The independent men who genuinely know these engines are retiring one by one, their waiting lists run to weeks, and every job that involves the word "access" gets the teeth, the tutting, and a number with a comma in it.
So the belief settles in, and you will have heard it at every club night and every show field in England. You only run a V12 if you can pay another man to look after it. I nearly swallowed that one myself, sat on a stool in my garage with raw knuckles, looking at a nut I could touch and could not turn, doing sums on what the car was costing me against what it was worth. My wife brought a cup of tea out and did not say a word. After forty one years she knows the difference between a man who wants company and a man who wants a minute.
You can get two fingers on it. You cannot get a spanner square on it. That gap is the whole story.
Then an old Browns Lane fitter put a bar in my hand
Den is seventy four. He spent thirty one years on the line and in the rectification bays at Browns Lane, Coventry, and he has a one man unit on the industrial estate now where he sees the cars he used to build come in on trailers. His rule has not changed since 1974. Right first time. I told him about the inner nuts, the rounded corner, the quote with the comma. He did not laugh and he did not suck his teeth. He went to the bottom drawer of an old wooden cabinet and came back with a flat steel bar he had made himself, square drives at both ends.
He had me press the drive end with my thumb. Something gave, very slightly, inside the steel. A roller chain, sealed along the length of the bar. "The chain carries the turn round the bend," he said. "You come at the nut flat from the side, where the room is, and the pull lands dead square at the other end. It cannot fold, there is no hinge in it. It cannot walk off, the drive never lifts. I made mine in 1981 because the rectification bay had the same problem you have, son. Somebody finally builds a proper one. Buy the real article and leave the copies alone."
"The chain takes the bend for you."
A slim, dead straight bar, about half an inch thick, that slides flat into the gap between the manifold and the rail where nothing else fits. The sealed roller chain inside carries your pull round the offset and lands it square on the nut. It is called the Savary offset wrench, and it is the bar Den spent half his life making by hand for the lads in the bay.
The sealed chain is the trick
A roller chain inside the steel body carries torque round the bend, so it never folds like a flex-head or walks like a universal joint.
Slides into the gap
A slim half inch thick bar slips down between the manifold and the chassis rail where no ratchet can swing.
Takes your own sockets
Square drive at both ends fits the sockets already in your chest. Holds real torque, up to seventy newton metres, a shade past fifty foot pounds.
It reaches. It is honest.
This solves access to a fastener you cannot get a tool on. It is the right shape for this engine bay, not a miracle for a stud already rusted to nothing.
It only comes from one place
You will not find it at Halfords and you will not find it at the autojumble. The maker sells direct from their own site only. Sixty nine pounds, shipped tracked to your door. That is less than one hour of any specialist who will still take the car, and a small fraction of the estimate with the comma in it, for the one tool that turns the job everyone dreads into a quiet Saturday morning with the radio on.
What happened next
Other owners who stopped paying for access
"Did the inner downpipe nuts on my own drive without dropping the steering rack. Twelve years I have owned this car and paid a man for that job twice. Never again."
"On a Series 3 the book answer for those studs is hours of dismantling. This bar came at them flat from the side. My hands have not fitted in that bay for twenty years. The bar does not care."
"Bought a cheap chain bar off eBay first. It folded on the first proper pull, exactly as warned. The real one from the maker does not give a millimetre. Chalk and cheese."
Den made his own in 1981 because Browns Lane never had to undo what it built. Now there is a proper one, and he is passing it on.
Get yours before the show season runs out
If you run a V12, or any classic Jaguar where the nut you need sits an inch past the spanner you own, you already know exactly what this is worth. And if you have been telling yourself you are getting too old for that engine bay, it was never your hands. It was the shape of the tools.
The Big Cat Field Notes is a reader-supported publication. This is a first-person account from a private owner and reflects his personal experience. The Savary offset extension wrench is a hand tool designed to reach fasteners in tight, blind locations. It improves access; it is not represented as a remedy for fasteners that are corroded or seized beyond normal service. Always follow proper service procedures and torque specifications. Results vary by vehicle and condition. This publication is not affiliated with Jaguar Land Rover.
