“Free to a Good Home” XJ-S V12

It’s been a few weeks since I updated this, but things have been progressing. The front right suspension has been rebuilt along with the brakes. I got the sway bar bushes out, had a hell of a time getting the new ones to fit and eventually realised that they were 3/4” XJ6 bushings rather than 7/8” XJS bushings. SNG apparently wasn’t paying attention when they packed the suspension rebuild kit. I got some polyurethane ones from XKs Unlimited, they arrived today along with new links, managed to destroy one thread on each side while disassembling things. I had a similar experience with the tie rod ends. Got the old one off, the new one has a different thread. Turns out there are three different parts depending on year, I had the most recent ones a need the middle ones. New new parts have arrived but I haven’t tried them yet because...
While waiting for front end parts I decided to tackle the rear brakes. Do date the rear axle is down, but still under the car. Once I’ve figured out how to undo the handbrake cable I’ll pull it out the side. It actually came out pretty easily. I was expecting the radius arms to put up a fight, everyone says they do, but they didn’t. One popped right off, the other started to tear and then popped off. The hardest thing was removing the flexible brake hose. I got the hard line detached, and could get a wrench on the locknut, but I didn’t have room to swing it. That ended things yesterday. This morning I went and bought a 15mm brake wrench. It didn’t quite fit, so I had to grind the outside a bit, but it worked eventually. Then eight bolts out, lower the jack, and I have a two wheel car! Now it’s time to go to my job. In the morning I’ll undo the handbrake and pull the rear end out the side.

Well, six weeks after I dropped the cage, it is now back in. So what did I do in that time? I kinda accidentally took it more apart than I meant to. Oops! I wanted to change the brakes, So I needed to take the cage off from the rest, which I did easily enough, but I managed to disturb the fulcrum bearing seals and spacers in the process. I ended up with three assemblies, the differential and two halfshaft-hub-wishbones. Everything around the differential was covered in a thick layer of grease and sand, as if the diff had been leaking and the car was driven on dirt roads. I got that all cleaned up and drained the oil from the diff. Since this is a Dana diff there isn't a drain plug, so I took the filler plug out and tipped the whole thing backwards over an oil drain pan. Then I took the cover off. The gears looked great, so once I got the rest of the oil out I sealed it back up and refilled it. The calipers were quite rusty and seized, so remans were obtained. There were a pair of rear brake disks in the trunk when I bought the car, I tried to put them on but the bolt hole patten was incorrect. The diff has a rectangular pattern and these disks have a square pattern. So then I measured the old disks and they're still at 0.500", so I put them back on. New calipers and brakes pads, with the old handbrake parts then went on. I took this opportunity to clean up the cage with a wire brush on a drill. Lots of dirt, grease, and a little rust came off, then it got a coat of black paint. 
The fulcrum bearings were the next thing to address. Bearings don't seem to be the best idea in that particular application, they hardly turn but have quite a bit of weight on very small rollers, which is a great recipe for flat spots. So I decided to replace them with some bushings. I bought some bronze rod and with the help of a neighbor turned up eight bushings. I pressed these into the wishbone arms. 
I had a great deal of trouble finding enough metlock nuts to attach the drive shafts to the differential. Four hardware stores to get eight nuts... But eventually they went together using the shims that had come out. Then it was time to put the cage back on and start lining everything up. Turns out a 2' 3/8" socket extender is the perfect tool for lining up the fulcrum shafts. I did decide to replace the shocks, they weren't original and might have been ok, but they're a pain to get at with the axle in the car. So those were put in around this point in the story. Eventually everything was back together. Getting the rear suspension back in the car was probably the hardest part of the whole process. I've been working on a gravel driveway that turns to dirt now and then, so moving things around isn't as easy as it would be in a garage. With quite a bit of help from my father, a board, some pvc rollers and a few prybars we were able to get it into a place where it could be jacked into position. It was a sweaty hour for the two of us to move the IRS from next to the car to back in place, but it is now bolted onto the car. Soon I will be able to attach the control arms, driveshaft, exhaust, and brake line. 

TED_fiestaHP said:

  I always liked these, somehow I haven't bought one.  I will follow along, should be a interesting build.

     I have heard it is set up as 2 six cylinder engines, 2 separate fuel injection systems.  But I have never worked on one.

        I does look rather complex.

           I did hear the air filers limit air flow, might be some untapped potential available.

 

 

To a complete novice it's absolutely terrifying. But U tube explains it all. Once you understand it's really a simple system.  It's weakness is the same as any earlier fuel injection system. No OBD2  plug and play replaces a lot of knowledge. 

In reply to garethashenden :

The differential has a limited slip ( positraction ) it will need a supplement or the clutch plates wear too fast.  It's available at most parts places and Chevy dealers. 

In reply to garethashenden :

All the nuts and bolts up to the early 90's was SAE fine or coarse thread. 

TED_fiestaHP said:

  I always liked these, somehow I haven't bought one.  I will follow along, should be a interesting build.

     I have heard it is set up as 2 six cylinder engines, 2 separate fuel injection systems.  But I have never worked on one.

        I does look rather complex.

           I did hear the air filers limit air flow, might be some untapped potential available.

 

 

You're thinking of BMW V12s.  Jag V12s are pretty "normal".

There's been a water leak since I'd owned the car. I was suspecting the windscreen, so I removed the A pillar trim and quickly found it. The top left corner had perished after 33 years, unsurprisingly.  I ordered a new gasket and locking strip and changed them this weekend. The glass came out fine, the old sealant mostly came out fine, but putting it back in was a monumental PITA. I tried to fit the seal to the glass, but it was way too big. So I fitted it to the car and it was still too big. I cut out about an inch and glued the ends together, then tried fitting it to the glass again. Still too big. So instead of putting the glass and seal onto the car and then using the string method to attach them I did it the other way around. The string was mostly useless, except for the last 6". The bottom went in fine, and the sides were ok, but the top corners were something else to fit, my thumbs still hurt two days later. Eventually the glass was fully seated in the gasket. Yesterday I went back and sealed the gasket to the car and the glass to the gasket with silicone sealant, following the procedure in the manual. Then I fitted the locking strip which expands the gasket to get a better seal. This was straight forward although the last corner was difficult because it had no where to move to. A couple of hours after I finished there was a thunderstorm and the inside of the car remained dry, so I'm calling it a success. Just need to reinstall the trim.

I had the same issue with mine.  I sent it to the body shop for a complete strip and glass-out respray, and I wanted them to reinstall the glass because I didn't want the responsibility.  They called me and said the gasket's too big.  I ordered another, same thing.  I told them to just try it and sure enough it went.  I bought this stuff specifically made for windshields by Permatex, it's like a really thin, runny silicone.  I went around the whole gasket with a bondo spreader, lifting it and running a "bead" (seriously it's almost water-thin) of this stuff just as a precaution.  No leaks ever.  And my floorboards were a moldy swamp before.

Wait until you have to do the rear window.......

There's one local to me for sale with a missing title, 44k miles, white w/ white leather that looks really good...$2500 asking

I'm VERY tempted

russde said:

There's one local to me for sale with a missing title, 44k miles, white w/ white leather that looks really good...$2500 asking

 

I'm VERY tempted

Seen it on CL, $2500 and missing the title? Unless you know some missing title magic then for sure pass on it.

In reply to yupididit :

Missing the tittle it's a parts car and prices for those drop deeply.  I'm in Minnesota and with a noterized bill of sale you can post a bond and get a provisional tittle that validates in 3 years and your bond is refunded.  Other states have even more lenient rules. While some are absolute!  No tittle no registration 
Assuming it's a running driving car the very top price that should be offered, ( minus the tittle ) no rust, running driving car with no issues is $1200 . 
Not running or running poorly it drops at least another $500 

There is a market for the early ones 1975-1980 because of limited production and they have the best potential for power.    
There has always been a demand for the earliest V12's to the point where complete engines have sold for $2500 since they have carburetors  and most came from XKE's  if it has a manual transmission behind it the value goes up another $1000. 

Darel said:

TED_fiestaHP said:

  I always liked these, somehow I haven't bought one.  I will follow along, should be a interesting build.

     I have heard it is set up as 2 six cylinder engines, 2 separate fuel injection systems.  But I have never worked on one.

        I does look rather complex.

           I did hear the air filers limit air flow, might be some untapped potential available.

 

 

You're thinking of BMW V12s.  Jag V12s are pretty "normal".

You have that part right. The filters don't hurt performance, the air cleaner housing does. 
In order to keep the engine quiet the used a reverse funnel on the air cleaner that limits air drawn in ( but does so quietly) if you remove that funnel you'll pick up 20 horsepower. If you run a duct from in front of the radiator to the air cleaner by picking up cool air you'll gain another 10 horsepower. 

I should update this thread more often, but I seem to only do it when meaningful events occur. Today I had my first test drive. Unfortunately it was a grand total of 60 feet. I backed down the driveway and stopped to check for traffic. The sun was in my eyes, so I stayed stopped for a minute and then the engine died. There had been a lot of smoke from the exhaust when I started the car, but now I noticed it coming up around the hood too. I'm pretty sure this is oil/penetrating fluid/cobwebs that are burning off the exhaust, but I let it sit for a while extinguisher in hand just in case. The smoke did go away after about 10 minutes, so I started it up again and drove it forward to where its been parked for the past few months. 30 feet in reverse, 30 feet total. Not a lot, but its the first time its moved under its own power in 5 years. Tomorrow I will try to set the idle, since its really low right now. I think thats why its cutting out. Then maybe a "proper" drive. Think it will make it a mile?

In reply to garethashenden :

Idle speed on a V12 is about 600 rpm. Maybe 650. But if if you listen to the exhaust it sounds like 1400 rpm because you can clearly hear each cylinder. 
 

With a V8 you hear 6 cylinders and a stumble.!  

In reply to frenchyd :

When it idles now, the tach says 200, maybe 300. 

In reply to garethashenden :

Check to make sure all 12 cylinders are firing. 
A digital infrared thermometer is the easiest way.  Aim the red dot at each exhaust port.  You might find that one side isn't firing. 
You really should have one of those for so many things on a V12. You can check the coolant temp anyplace on the engine. Check the radiator, see if it's plugged. Check oil cooler etc etc. 

If you don't have one use your kids light colored crayons. Draw a mark down the exhaust manifold.  When it melts that means thacylnder is firing. 
 I've got a light that I put on wires to make sure each cylinder is getting a spark. 
I also listen to each injector  to hear it ticking away to make sure they are firing.  Since all that is right on top  it's easy to do. 

I have successfully driven the car on a short trip. I went half a mile down the road to the town's cemetery, took a couple of pictures, and drove back. The coolant gauge isn't working and there are a couple of warning lights, but everything else that I tried works. First, second, and reverse gears work, didn't get going fast enough to get to third. Really satisfying after all this work.



 

So I've had a month or so of a driveable XJ-S. At first I wasn't sure, lots of squeaks and bumps. I'd already rebuilt the suspension so I was a bit worried I'd done something wrong. The transmission mount needed to be replaced, a pothole hit in the wrong way would cause the transmission to hit the underside of the floor. That was alarming the first time it happened. I had a shop do it. I wasn't comfortable lifting the car that high on a gravel driveway. The transmission mount had completely disintegrated, so the squeaking I was hearing was the transmission bouncing up and down on its spring. The driving experience was completely transformed. If you haven't done it, you should. The other thing that got fixed was an exhaust leak. I had thought it was the drivers side, under the seat. Someone has repaired the pipe there in the past and its hanging down a bit. I think it is leaking a little, but the big problem was on the right side at that same joint. It was very perforated. Much quieter now. 

I have been having a bit of a fuel smell issue though. It seems to be the season for that as there are a couple of other threads going on at the moment about solving this. I think I have an issue with the venting system, as there is almost always a rush of air when I open the fuel cap. But more importantly, there is a fuel leak in the trunk. There is a bit of a fuel smell outside the car, but when I open the trunk lid the smell is overpowering. I need to let it air out for at least five minutes before going near it. When I removed the spare tire there was a wet spot at the bottom of the trunk. I cleaned it up, tightened all the hose clamps, ran the car, and it stayed dry. So I thought I was good. A few hours later I went back and not only was the floor damp again, but the vertical surface up to the tank was wet as well. I think there is fuel weeping out the bottom of the tank. Its not gushing out, but its not staying in either. Which means that I get the super fun job of removing the tank and repairing it. Oh joy. I did look inside the tank early on in this thread and I thought it looked pretty good, but it doesn't seem to have held up. I suspect the venting problem has contributed to this just as much as rust has. Drawing fuel out without letting enough air in can stress the seams. Hopefully I'll be able to repair the tank rather than replace it. And of course I just filled up with gas, so I need to drive more first. 

In reply to garethashenden :

If you haven't replace all your fuel hose ( especially the short injector fuel line do not drive the car!!  
Fire danger!   
     

There is a design flaw in the tank.  It's made of a top and bottom half.  There are baffles spot-welded into the bottom half, then the top half seamed to that.  However, the baffles are just standing in there upright held in place only by the spot welds on the bottom of the tank.  So over the years the fuel pushing on those baffles as the car corners cracks the spot welds.  You'll need to pull the tank and have the spot welds re-welded.

Any updates?  

Delightful to read about someone taking care of a Jag.  I have never really been a fan of the XJ-S Coupe, but the XJ6 and XJ12 sedan...  Oh my...

Well I haven't updated this thread in a while have I? But I haven't been completely idle. Got the car out of storage in early April. It started up pretty easily, third or fourth time I cranked it over and ran fine. Brought it home and parked it in the driveway. It was obvious last fall that it was leaking gas and the car failed to magically fix itself over the winter. It seemed there were two options, replace the tank with a new reproduction from SNG Barratt ($610) or clean and seal the original tank. Sealing the tank seams like quite the labor intensive process that I wasn't interested in doing myself. I've also read some rather mixed reviews of all the products on the market. I considered having someone do it professionally, but that would have raised the cost without necessarily increasing the finish result. So I eventually opted for the new tank. I saved myself $43 by going and picking it up in person, just over an hour away luckily.
Drained the gas, pulled the old tank out, then let the car air out for a week while I figured out what to put under the tank. Someone had been in there before me, there was something JB Weldish on the outside where they had tried to patch things. Under the tank was an aluminum covered piece of foam. I opted for the furniture mover idea, adhesive teflon and foam disks stuck to the body of the car. I think I got a 20 pack and used them all, someone on Jaguar Forums had done that, that's where the idea came from. Seems to give a good support but not let water pool anywhere. We shall see if it holds up. New tank in, start attaching connections, oh wait. The outlet has a threaded fitting on the original tank but just a pipe on the new one. There's a flare at the end, but now I need some fuel hose. It took ages to find 1/2" ID fuel hose. I could order some from Amazon, but only if I want 25' of it. I needed 2' max. Eventually I found someone selling 5' sections on ebay. I probably overpaid, but I don't really care. The fuel system is now plumbed up and working. Put a couple of gallons in from a gas can and no leaks! Drove down to the local gas station and started filling up. I had the trunk open so I could watch for leaks and I'm glad I did because it soon started pouring out of the fuel sender hole. It had felt a little funny going back in, and hadn't seated properly. taking it out and putting it back in solved the problem and the whole tank now holds gas.

So on to the car's main problem. The cooling system. when traveling more than 30 mph the cooling needle is halfway between C and N. It reaches N in traffic and will presumably keep going but I haven't been that unfortunate yet luckily. So I need to do something about this. I've opted for Do it Right, Do it Once, Do it All. The radiator will be replaced with a new aluminum one from Wizard Cooling, I opted for the most powerful of their electric fan options, two big Spal fans. I'm also replacing the waterpump, thermostats, heater valve, and all the hoses. Got a rebuild kit for the AAV from Jag Improver, so that will get redone. There are also some stainless water rails, which I think came from ebay but I can't remember. Bought them last summer. While I'm in there I'll be replacing the alternator with a more powerful one. I suspect the nearly 40 amps the two fans want would make the stock alternator rather unhappy. My current plan is to replace the air pump with a CS-130 style alternator. This would reduce the car to only two belts. If that doesn't work then I'll put it where the stock alternator is.
I spent most of Saturday tearing things apart. The thermostats on the car are very clearly marked 74C, which is probably why the car was running so cool. The coolant is not the bright green that it should be, except for the atmospheric expansion tank. This suggests to me that it may not really have been doing anything. I didn't really have any trouble getting things apart, particularly if we overlook the time I missed half the bolts holding the water pump on...
I need to clean up all the sealing edges, then I can start putting things back together. But first I really need to order that alternator.

The current state of things:

Glad to see this back.

garethashenden said:

Well I haven't updated this thread in a while have I? But I haven't been completely idle. Got the car out of storage in early April. It started up pretty easily, third or fourth time I cranked it over and ran fine. Brought it home and parked it in the driveway. It was obvious last fall that it was leaking gas and the car failed to magically fix itself over the winter. It seemed there were two options, replace the tank with a new reproduction from SNG Barratt ($610) or clean and seal the original tank. Sealing the tank seams like quite the labor intensive process that I wasn't interested in doing myself. I've also read some rather mixed reviews of all the products on the market. I considered having someone do it professionally, but that would have raised the cost without necessarily increasing the finish result. So I eventually opted for the new tank. I saved myself $43 by going and picking it up in person, just over an hour away luckily.
Drained the gas, pulled the old tank out, then let the car air out for a week while I figured out what to put under the tank. Someone had been in there before me, there was something JB Weldish on the outside where they had tried to patch things. Under the tank was an aluminum covered piece of foam. I opted for the furniture mover idea, adhesive teflon and foam disks stuck to the body of the car. I think I got a 20 pack and used them all, someone on Jaguar Forums had done that, that's where the idea came from. Seems to give a good support but not let water pool anywhere. We shall see if it holds up. New tank in, start attaching connections, oh wait. The outlet has a threaded fitting on the original tank but just a pipe on the new one. There's a flare at the end, but now I need some fuel hose. It took ages to find 1/2" ID fuel hose. I could order some from Amazon, but only if I want 25' of it. I needed 2' max. Eventually I found someone selling 5' sections on ebay. I probably overpaid, but I don't really care. The fuel system is now plumbed up and working. Put a couple of gallons in from a gas can and no leaks! Drove down to the local gas station and started filling up. I had the trunk open so I could watch for leaks and I'm glad I did because it soon started pouring out of the fuel sender hole. It had felt a little funny going back in, and hadn't seated properly. taking it out and putting it back in solved the problem and the whole tank now holds gas.

So on to the car's main problem. The cooling system. when traveling more than 30 mph the cooling needle is halfway between C and N. It reaches N in traffic and will presumably keep going but I haven't been that unfortunate yet luckily. So I need to do something about this. I've opted for Do it Right, Do it Once, Do it All. The radiator will be replaced with a new aluminum one from Wizard Cooling, I opted for the most powerful of their electric fan options, two big Spal fans. I'm also replacing the waterpump, thermostats, heater valve, and all the hoses. Got a rebuild kit for the AAV from Jag Improver, so that will get redone. There are also some stainless water rails, which I think came from ebay but I can't remember. Bought them last summer. While I'm in there I'll be replacing the alternator with a more powerful one. I suspect the nearly 40 amps the two fans want would make the stock alternator rather unhappy. My current plan is to replace the air pump with a CS-130 style alternator. This would reduce the car to only two belts. If that doesn't work then I'll put it where the stock alternator is.
I spent most of Saturday tearing things apart. The thermostats on the car are very clearly marked 74C, which is probably why the car was running so cool. The coolant is not the bright green that it should be, except for the atmospheric expansion tank. This suggests to me that it may not really have been doing anything. I didn't really have any trouble getting things apart, particularly if we overlook the time I missed half the bolts holding the water pump on...
I need to clean up all the sealing edges, then I can start putting things back together. But first I really need to order that alternator.

The current state of things:

Don't go to Aluminum.  They are single pass and won't cool as well as the factory one will. The factory is actually a triple pass radiator and does a much better job of cooling. If it's filled with crud take it into a radiator shop to be rodded out. That's where they take the tanks off and push a rod through each tube.  
     I can use aluminum because I seriously modified the coolant system  to work. Plus no A/C  and much better airflow in the engine compartment. 
   For street use aluminum is a mistake.