1973 XJ6 S1 with AJ16 Supercharged - Project "Ropey"

[richw82]

Hi all,

A couple of years ago I was at a point in my life where I was about to do something terminally daft. I had gotten rid of all my projects, and with the money in my hand I was off out to buy a reasonable, usable modern car.

Thanks to a timely intervention by my brother, I regained my wits and spent my dosh on a 1973 Jaguar XJ6, that due to me buying it escaped the banger track.

I was happy with it. The 2.8 engine didn't do it any favours, but the manual gearbox meant it could be driven 'spiritedly'. I conveniently ignored impending water pump failure and the sound of the timing chain eating what was left of the tensioner, as I could always lay my hands on a spare engine. I nicknamed the car "Ropey" as it looked a bit ropey... but for all its faults it never let me down.

I never thought the engine would last as long as it did... it made it out to France for the Le Mans Classic, and covered some 12,000 miles before it finally let go. I commuted to work in it, regularly doing 160mile round trip to Coventry Airport in it.

The engine finally died in true 2.8 style, burning the top out of the no 1 piston on the way back up the M1 on the way back from Coventry. Testament to the engine's strength though, and its Le Mans heritage; it staggered on for the next few junctions and got me home... though the oil pressure and temperature weren't groovy by that point! Nor was the 2000rpm needed to keep it running at junctions.

About this time I decided it would need more guts. A 3.4 was fitted to get me through the winter (anybody that says a big Jag can't handle snow is a liar... so long as you don't beach it on a drift, you're fine) but plans were made to give the old beast a bit more go.

An XJR-6 donor engine would do the trick. That set me on the course I am following now, so with a a little help from ebay, I found myself a replacement engine.

More to follow...

[richw82]

So this was what I started with.

Believe me when I say it looks better in the picture. It doesn't show the kink in the roof the hiab put there, or any of the bad dents/welding/cracked paint.



When the engine lets go, it has to come out. If you've never done one of these, there is a little trick. Drive the car onto a couple of bricks, and you won't curse the thing for being too low to get the crane under the front...





Closer inspection proved this wasn't the first time it had thrown a tantrum. Or a rod..



So now I had to figure out a way to put some supercharged goodness into the oily 'ole the XK engine left behind. I hit lucky, the donor engine had the supercharger and most ancilliaries still attached, and most of the wiring loom. No ECU's with it, but 79,000 miles, which is roughly what the Series 1 had on the clock.

All for £310. Bargain! Time to get the crane out and grab a quick brew.

[richw82]

Hanging it off the engine crane it was evident that it weighs significantly less than an XK unit. It made life a lot easier than usual.



Once in, I got the support beam on it so I could put the car back on the garden rather than the garage site behind the house.





A couple of bricks and a dod of wood now supported the rear until I could find a reasonably priced 5 speed box and some other gubbins. The engine was sat right where it should be, and didn't foul the rack, crossmember or anything that was important. The bonnet fits without fouling, and I was pleased with how it looked under there.



The next step was to find and kill an XJS 3.6 as I needed some more parts.

The most important bits I needed were the 3.6's engine mounts, and the 5 speed Getrag gearbox to hang off the back of the new engine. That way I didn't have to worry about gearbox ECU's or any of that dual mass flywheel nonsense. The propshaft would need changing but that was a worry for later.... the E-type lads use the Getrag box so it shouldn't be hard to find.

The other good part on a 3.6 manual XJS - it has a 3.54 : 1 limited slip diff. Way better than the 4.55 : 1 on the 2.8 XJ6, and much better suited to my targeted top speed of 160mph.

[Relentless Rob]

Brilliant project!

Welcome to the forum.

[richw82]

Cheers! Got some more to post yet to get it up to date. I got hung up recently with the electrics so its progress has halted, but I'm not giving up until its done.

[richw82]

More....

I acquired a 1984 XJS 3.6 which had a whole heap of parts on it I need. Despite it being fairly much a shedload of filler in a vague XJS shape, it drove well and was pretty quick, but on viewing it in daylight I'm glad I drove it home from Norfolk in the dark.

The Getrag 265 in the XJS is healthy and I love the firm change. It's still nice and long throw (I can't be doing with short levers... Mum's MX5 is horrific.) and light years ahead of my old 4 speed and overdrive, though I need to investigate keeping the old chrome gear lever if I can...

The back axle is the PowerLok 3.54 : 1 item, which means in 5th, 60 is achieved at around 2,000rpm. As the AJ16S redlines at about 6,000 it means a 150mph top speed will be easily achievable, but 0 - 60 should be rapid. The diff on the XJS was tested thoroughly on the way home. Spending a day messing around in the sun, it wasn't long before the XJS had donated several bits. I got the radiator in position, and the coolant expansion tank and I was pleasantly surprised to find it all fitting rather well. So far - no cutting!

Once I'd got the engine, box and back axle out, the rest of the XJS was stripped and disposed of fairly quickly. Some bits I hoped would fit didn't due to being damaged, corroded, or just wrong shaped.

I lost the rack, and the front subframe was corroded beyond use. I will be sticking with the Series 1's own suspension as a result, but I'm going to get the later springs to drop it a little, and the roll bar and shock absorbers will be uprated to suit.

Jag myth busting -

1. The engine mounting towers on the XJ subrame are interchangeable between XJS and XJ6. Bolt holes exist for both.

2. Engine mounts on the engines themselves are interchangeable between AJ6, and AJ16S.

I got the engine bolted in properly, and kept the rear in place with a support beam. I then had to get the manual flywheel on in place of the flexplate. The mounting plate behind this is different and has to be changed. The AJ6 has a separate crank seal and housing, the AJ16 is integral with the mounting plate.

More Jag myth busting -

3. Despite one being separate, and one being integral, AJ6 and AJ16 rear crank seals are compatible. Bolt spacings are identical but you have to change the entire set up from one to the other.

Cooling was a nightmare to figure out, but the intercooler pump, heater piping, and routing for the intercooler radiator are in place. I had to buy an intercooler radiator, and was pleasantly surprised to find the stock XJR-6 item fits neatly in the S1 XJ6 grille aparture.

Vacuum for the brakes has used some of the stainless tubing scavenged from the XJS air con system, running across the bracing bars. It was planned as a mirror image of how vacuum is piped on the US market cars. It looks pretty good, and didn't need bending.



I spent the next day wrestling a Getrag 265 and bellhousing under the car. After several times where I cracked my head on the jack, the dust blowing, the pet cat getting in the way, and gear oil, I looked like a Mad Max reject.

The Getrag is going to be a nicer box to use than the old Jag 4 speed and overdrive. While the old box was nice with a good change it had several faults-

1. Low oil drops the overdrive out
2. Knackered lock out switches drop the overdrive out
3. The heat fries the wiring and drops the overdrive out

See where I'm going with this? Also the new box has a proper spigot bearing, and release bearing. The old one is graphite and looks like a hybrid of an instrument of torture and an artists tool. Careful use of the trolley jack got the box in position, and I cheated to line the bellhousing up with the engine by using some long bolts I had lying about. I then surprised myself by giving it a quick tap with a mallet and the damn thing mated first try!



I had two other things to get done under here, one was fitting the gearbox mount, the other being to figure out what the hell to do about the speedo drive. The speedo drive turned out to be relatively easy, as the tranducer screws into a normal output:




So all I have to do is find an XJ40's angle drive to go on there. I did try the one off the old gearbox but one is metric and the other is imperial. Once thats done, a load of calculations and sending my speedometer to get regeared will see everything working nicely.

The mount turned out to be fairly simple too. The original XJ6 item is on the left, the XJS item on the right.



I used the XJS item, including its crossmember, it required drilling two holes into the car. Total modifications to the shell now stand at 5 small holes.

With all that done, I stopped to grab a Jaffa or two, then the postman pulled up outside with a load of exhaust bits. It would have been silly not to fit the downpipe with the car up on ramps so that got done while I was at it.

I dropped the car gently off the ramps and got stuck in under the bonnet again. New power steering reservoir in place and first of the new hoses. I reused the car's high pressure line, by using a pipe bender to make it clear the exhausts.



While I was under the bonnet I ripped out the old heater vacuum system.



It's a big annoyance of mine having to chase vacuum issues, when all you want is heat! The last winter season was driven with cable ties holding everything that makes hot air wide open, and it proved that Jag heaters are more than capable. I intend to replace the vacuum lines with cables, though that's for a little later.

Last job of the day was to start putting the wiring in, preparation for rigging it up in some crazy Lucas/Frankenstein inspired style. I'm seeing XJR6 wiring diagrams when I close my eyes now having been studying the damn things for a couple of days. There are a good few wires in there that it can live without!





Feeling happy with my progress I turned to the starter motor and electrics. Fairly easy to wire in the main positive feed for the electrics is on the passenger side, fed across to the drivers side (where the solenoid is) on the original engine.

By taking the main feed off the solenoid, you can run a cable to the new starter which is about 8" away from the positive feed instead of all the way across the car.

Find the red and white wire from the starter relay, and wire up to the new starter..

Add battery, turn key..

And we have an engine that turns over on demand! Now I just have to get fuel up to it and the electronic brains in place.

[Relentless Rob]

Local eh?

Thought I recognised the Triumph. Are you the chap I sold my red and white Herald convertable to?

[richw82]

No, I'm in Derbyshire! I bought the XJS donor in Norfolk though, and drove it back up the A1.

The red Spitfire belonged to my brother. He sold it a few months back and its now in the Czech republic.

[Relentless Rob]

Ah, I see. My mistake. There are a lot of forum members in your neghbourhood so if you ever get stuck I'm sure they'd be happy to help.

[richw82]

A few of us up here? No doubt a couple of us will have met and not realised it then.

Anyway.. sometimes things get you down (electrics!), so I nipped over the border into Wales to raid David Kelly Jag Breakers for some much needed parts.

The main items I needed were two injection fuel tanks, which put up a good fight but came out (at the cost of two knuckles), and this:



The chrome bezel item is the original 2.8 speedo from my car. The other is a mega rare series 1 V12 speedo, which goes up to 160mph! Perfect for an XJR6 engined car.

The only problem was that it isn't done to have one black rimmed gauge in a sea of wood and chrome. So it needs to acquire some shine, and quickly.



Take the bezels off (carefully!)



Swap and refit, and hey presto! A chrome rimmed 160mph S1 speedo. I'm not sure if these ever existed from the factory - but what the hell. Needs must and all that, and it will also have the local JEC old boys swallowing their beards in horror at what I've done (again...)

As I was messing about outside I strapped it back into the walnut plank that holds the others, just for a little inspiration.



It looks fantastic! I can now measure 6500rpm, and 160mph - as long as I can figure out where all the wires go... which is what my next post is going to cover.

[richw82]

Right - essay time. I'm posting this to try and help those that follow this path after me, or attempt something similar, as getting information has bein a royal pain. Those that know won't share... and those that don't know make it up.

I intend to tell it as I've found it.

I went into this project with a clear idea of what I wanted to achieve. The idea being to use as many off the shelf Jaguar components as I could, and try and keep a look to the car which to those not in the know wouldn't suggest it was anything special or different.

The engine, gearbox and other ancilliaries all played ball. The XK engined XJ6 formed the basis of the V12 car, which then became the XJS, which then got the AJ6, and subsequenty AJ16 engines. Evolution put me on safe ground as all these variants shared a common front crossmember - due in part to the AJ6 getting tested in the series 2 XJ6 in the mid 1970's.

What I didn't account for was the influence of Ford, and the struggles the electrical system would pose. I set about trying to use the original ECU from the XJR. This unit is part no LNA1410. Various unscrupulous ebay types try and pass off the non supercharged item as the same thing, but it is not.

So now you have the ECU... but it still won't run. This is due to the fact that the immobiliser on it requires an RFID chip, and the associated reader, and security module (which are matched sets of items to each car) before it will activate the starter circuit, the fuel pump or the injectors. I thought I fooled it by cranking and running the fuel pump off the cars original wiring, but it didn't activate the injectors.

North American spec XJR6's don't have this feature in their ECU, so getting hold of one from the USA could work. Similarly, you can use the ECU from a 4.0 facelift XJS - part no LNE1410, and swap the chips from an XJR6 ECU into it. The XJS ECU is very difficult to find.

The last option is to send it away to an 'expert'. There are a couple out there that want to charge a crazy amount of money (£450 last time I checked) just to remove the immobiliser.... nothing more. Hardly seems worth it when the same experts can't remap it, or even alter the timing for you.

Once you have overcome these immobiliser issues you then have to contend with the fact that your ECU probably came from an automatic car. It will be looking for a gearbox ECU, and a torque signal, which if not found cause it to go into a limp home mode.


The struggles mentioned up here are the reasons why despite the AJ6/AJ16/AJ16S being a good power unit, it is rare to see one used in a swap. The engine management is far too over complicated.

With my XJ6 project, I have started looking at Megasquirt to run the engine, as it will simplify things greatly. I might have to get the car mapped when it is finished... but at least I have the choice and the tools are available to do the job.

This is where I am up to, to date. Further updates will be posted as I do the work.


Cheers,

Rich

[TeamTotalWankel]

Good work Rich, liking this a lot
You are a total Jag slaaaaag!!

[Relentless Rob]

Is there an Emerald ECU option to suit the car?

That would cut out the immobiliser, you can set the rev limiter where you want and get it down to Mr Walkers to get the best out of it.

[Buddy]

There's an Emerald option for anything these days!!

I'm really liking this thread, Jag is way cool, is it tax exempt???
making a lovely job of it tho rich, keep the posts coming

[richw82]

Cheers Buddy. More to come when I get chance to work on it!

I've been messing with old aeroplanes lately so I've had less time than usual. Sadly the big Jag misses out on being tax exempt by 24 days. The heritage certificate I got for it shows a build date of 24th January 1973... though a lot of it was built earlier if the tags I found are to be believed.

If I'd thought of Emerald first I probably would have given it a shot. However, once I junked the Jaguar ECU and wiring I started collecting bits for Megasquirt. I also like the fact I can build it myself.

If it all goes pear shaped I'll have a look at the Emerald option.