Probably because the 6L80 has a similar 4 bolt output yoke to the XJS TH400 it does not use a slip yoke.

 

I'm glad to see that Robert's XJS is moving forward.

Just to clarify again on the different aspects and costs of the project, each of these were identified up front, before one dollar was spent or one screw was turned, as they are not mysteries. The driveline discussion has more to do with the fact that the 6L80E transmission, like most modern units, now uses a 3 bolt/rubber coupling style output rather than the typical for GM slip yoke, or the Jaguar GM-400 style 4 bolt flange. Something different was needed in this case, and what Robert has now is one good solution, and there are others as well.

Regarding wiring, this was also a known project up front- the installer or another company would need to modify the harness and do some reprogramming on the ECM to make it ready for the Jag, or go with an aftermarket harness set up for conversions/retrofits such as this. Either way is nothing special and pretty much par for the course for a project of this type.

This is a very advanced, interesting, and ultimately worthwhile project, and yes, more complicated than a garden-variety carbureted small block Chevy conversion instead. Additionally, rebuilding the V12 really isn't a practical option- here in the US, the cost to do that (V12 engine rebuild alone), and then install it properly in the XJS, would be roughly the same as what Robert has spent so far on the entire conversion. He would then still have to live with the V12's "idiosyncrasies", as well as an ancient 3 speed automatic transmission (or opt for an overdrive transmission retrofit, a possibility, but a $3500 option, all told, at minimum, including labor to install). Instead, he now has a modern engine (making some 450 reliable hp and 25 mpg) and a (6 speed automatic) transmission in a classic body. Also keep in mind that this drivetrain package has trimmed 350+lbs off the front end of the car- that weight savings is equivalent to another 150 hp, so the performance should be impressive. This is not for everyone, but to each his own.

Also, let's be sure not to confuse a DIY approach to Robert's cost here- Robert is having a professional shop do the installation and there are labor costs that also are predictable. An end user doing the work himself would obviously have a considerably lower cost. Nearly 80% of our sales are to DIY individual end-users/installers and they generally march through the project, with our support during the build as they need it, with no problems.

One disappointment on my part is the very minimal communication I had with the installing shop during the process- quite frankly, they did not use us for support nearly as much as they should have. While all of the unique aspects of the conversion were foreseen (ahead of time, and discussed with Robert, also ahead of time), we were consulted (by the shop) very little along the way, which is a shame. I have 20+ years of experience doing Jag-GM conversions, including nearly 10 years on LS engines alone, particularly in this model. That knowledge could have been brought to bear in a much bigger way here, for both a quicker resolution of issues, and likely reduced cost as well. But someone has to call me. I spend a lot of time on the phone and Email with customers answering questions and clarifying the install process as it goes- this is a large part of what customers are paying for when buying our kits. It is normal.

To recap, again- when in doubt, call the supplier.....

I'm looking forward to Robert's car getting up and running- it should be quite a hoot to drive.

Thanks

Andrew
Jaguar Specialties

 

This is why I often suggest an LT1 conversion for those on a budget. 280HP stock and 350HP with mild upgrades can be done for about $3000 to $8000 depending on the level of DIY.

Quite frankly the LS3 is going to overwhelm the XJS chassis in stock trim. Without additional upgrades to the brakes, suspension and contact patch all that power will be unusable and possibly dangerous in inexperience hands.

 

Well, even the V12 is a dangerous engine for inexperienced and even sometimes experienced hands. The XJ-S is a "little" nippy on the rear...

Once I have mine all together again and she's registered, off to a driving seminar to train for the situation everyone hopes not to get into

 

Exactly. It's going to be a beautiful build. I can't wait to see the final results.

BTW, Andrew, my '91/LS1 build is in the "queue". I got sidetracked by a loss in the family, and then my water pump replace on my '94. I look forward to the work, hopefully during the winter.

Padre

 

Yeah but a lot of fun, the closer to the edge the higher the high.

adrenelin

 

Whatever happened with this project?

 

Funny you should ask (over a year ago).

Sorry about the abrupt stop to the updates, but the work abruptly stopped on my car. Andrew has been standing by me like a champ, but I can’t say the same for my garage.

To fill you in on the sob story, Ronnie, the mechanic that was working on my car and a partner in the garage the car was in, had a falling out with his business partners. One day he was there, and the next he was gone. I liked Ronnie, and he knew what he was doing, even if he refused to ever call Andrew.

However, when he left, no one there had any idea of how to finish my conversion. I got jerked around for basically the last year while they tried to find a mechanic to finish the car.

To compound matters, I relocated from Miami to Dallas last May and wasn’t going to ship an unfinished car. A new mechanic would have charged me for the full conversion project again. So I left it there and prayed.

Amazingly, just after I left they got a guy to work on it. I think they just wanted to finally get it out of there after a year and a half. Well, it has taken six months, but the car is now finished and shipped to Dallas yesterday.

It is not not all good news though, they didn’t really 'finish.' I won’t know what hasn’t been done until I see the car, but I know for one, they never installed the new springs and anti sway bar from Andrew. They can’t even find the parts anymore.

So be it. It is far enough along now where I can get a new mechanic here to close it out. I will know more and post some pictures and videos when it gets here in a couple days.

To end on a high note here is my car leaving miami.

(Edit-sorry,I could not figure out how to post a picture from my phone. Picture incoming)

 

Wow, sorry to hear you've been jerked around, but at the same time, happy to hear the Jag is out of purgatory and the project finally moving forward again.

Thanks for the update! I look forward to more.

 

Thanks for the write up...

Is the 6L80 mounted further forward than the T400 was?

 

Andrew a 350lb weight saving is not equal to 150hp.

I don’t know what parts were provided but with tail shaft issues, sump problems, etc the kit seems far from fool proof, complete or tested. Was this car your development car? I would I imagine a diy guy would have even more problems than a mechanic.

 

Rsmithline sorry to hear about the drama. I hope you are enjoying the car soon. The ls3 and 6l80 is a sweet combo.

 

First of all, here is the promised picture of my car coming home:




As you can see the front end is riding pretty high until i get it here and get those springs changed out.

Thanks mate. I can wait to actually sit behind the wheel and punch the gas.

 

Actually about a half inch further back. When it was originally installed with the engine, it fit fine in the stock position with no major hammer-work to the trans tunnel. But the modification to the oil pan was already done and when we tried to install it, it didn't fit. We had to shift the whole engine back a quarter of an inch to accommodate the oil pan.

With a fresh build it should fit in the stock position if you are mindful of how much you need to chop out of the oil pan.

EDIT - Keep in mind will still needed the custom mount from Andrew to install it. It is very nicely fabricated piece though.

 

Thanks for the write up and pics. What do you estimate the total cost will be?

 

I stopped tracking every cent when i was at $20k, but all in, in the $25k range. Maybe a grand less.

 

Hello all, this is Andrew from Jaguar Specialties

It's great to see that Robert's project here is moving along again.

I just wanted to make a small clarification here. Our LS-XJS kit was designed some 8-9 years ago around the most common LS engine and transmission combination out there- the LS and the 4L60E transmission (4 speed auto overdrive). The kit works with basically any LS engine, dressed appropriately with the correct oil pan, exhaust manifolds, accessory drive pieces, etc.,., all of which are GM parts, not aftermarket. Once the engine package is prepared properly as above, the package (with 4L60E transmission) slips into the car with no modification on the car itself- it's a bolt in. And all of the subsequent steps to complete the car are neatly detailed out in our conversion manual- nothing is left open or unaddressed. When completed, these cars appear and function as they did originally- the factory gauges all read correctly, the shifter works perfectly with the new GM transmission, the AC works even better (because we use a modern AC condenser of proper size) and we can even utilize the factory cruise control. This is how conversions are supposed to be.

Now a few years later. we have several hundred LS powered Jags of all types running around all over the world (we have kits for XJ6 XJS XJ8 XK8, etc.,.) and the vast vast majority of them running that most common 4L60E family of transmissions. (and a few 6 speed manuals, etc.,.)

Robert's engine package here is very different than the standard package the kit was designed for. It can be made to work with our kit in general, but requires some modification to our parts. Also, since these packages are still pretty pricey (about 2x+ of what a typical LS1/4L60E package, or 4x what the truck LS packages cost), few customers decide to go this route (like single digits...). That also means there is little customer draw for us to go back in and re-engineer the basic kit to accommodate these new drivetrains (and there are probably 4 or 5 newer variants)- hardly anyone is asking about them. It's not practical to cover them all- you put your R&D $$ and support behind the package(s) that represent 95% of what customers are doing.

In that vein, all of this was discussed, in detail, with Robert before one dollar was spent and one screw was turned. He understood and was aware of all of it. We committed to support the build (make suggestions on kit modifications, help solve problems, etc.,.) as needed and have done so, although (unfortunately) Robert's original mechanic used us that way very little. You will see examples throughout the thread where we were called late in some crisis moment to easily help resolve an issue.


I would also make a humble request that before coming to any conclusions or making statements about the completeness or thoroughness of the kit or the conversion process, please read through the whole thread to understand the history.

If there are any questions, let me know

Andrew
Jaguar Specialties

 

Thanks for chiming in Andrew.

Just in case anyone is not clear, Andrew went over all of the issues we would have with this conversion before we started. The problems encountered are largely due to a poor choice in auto shop to do the work.

Also, I can't say enough about Andrews support. It has been over a year and a half since I got the conversion package and he still answers my texts right away and is more than willing to jump on the phone with a mechanic.

In ordre not to clutter this message I will post what happened when I got my car an hour ago. It is not good news.

 

The first time, I opened this thread the picture did not come through.


So, I rebooted the forum. works on lots of stuff. One step away from a percussion application.


That sure is a nice car. At least they cleaned it up before shipping it to you. I doubt it looked that way lingering in a corner of the shop.


Lost parts? Oh, me. But, at least not any that are hard or super expensive to replace.


It should be easier to find a mechanic in Dallas that can handle the spring swap part and the bar as well.


Now, our curiosity is whetted. Got to see the engine bay!!!!


Can't beat Andrews's support.


Carl

 

Well I finally got my car an hour ago...and i nearly cried. The car is a mess. The auto shop screwed up everything that could be screwed up. Lawsuit incoming.

This is my car as it came off the truck, not nearly as clean as it went on for sure. You can also more clearly see the nose lift since they never installed the bushings, lowering springs or anti sway bar.



You will also notice the hood no longer closes. I thought that may be an issue, but it only need another quarter inch to close and I think they could have manufactured that little bit of space. Incidentally the hood is all scratched up and chipped on the edges now....and they didn't bother putting the hood struts back on. And yeah, the caps are missing from both front tires.

Yet that is all trivial compared to the real problems. They didn't install any exhaust system at all. The engine is running open. It also barely runs. As you can see in the video below it is loud, stalls out regularly, and just sounds unhealthy. Remember this is a nearly new LS3 engine from a 2016 Camaro SS with about 20k miles on it. (after watching the video, it does no justice to how loud it is and how bad the engine sounds.)


When it drives, it is jerky and won't go over 30 miles an hour. However, the speed limitation may have something to do with this:



What the hell?! Who installs an accelerator pedal like that? Not to mention there is only about a half inch of clearance until it hits the floorboard.

And there are a slew of other problems; like the drivers window no longer goes down.

My seats weren't flawless, but now they are filthy and torn:



Also, half my gauges don't work including my speedo, oil pressure, and temperature. This is after I bought adapters for those from Andrew so they would work.

My trunk is a mess as well, they lost the covers for the battery and installed some kind of filter behind where the spare goes so I can't stand up my spare.





Oh yeah, no grill anymore:



I could go on and on, but I feel the tears coming on again.

At least Andrew has pointed me towards a real mechanic in Austin that will now take over the job, but that means it is time to spend again...on stuff I already spent to get done.

Well, I am going to go beat my dog for a while to feel better.. I will update you after the new mechanic takes a look and tells me everything else that was done wrong.