XJ6 & XJ12 Series I, II & III 1968-1992

Series 2 XJ6 / XJS suspension interchange?

Old 06-01-2016, 08:49 PM
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Default Series 2 XJ6 / XJS suspension interchange?

Okay, so it's an outrageous idea... But I'm wondering if the XJS suspension subframes can be installed in a Series 2 XJ6? Are the mounting points the same?

I'm looking at an XJS parts car and its AJ6 drivetrain, and wondered if both subframes can be bolted into my Series 2 coupe. If not, I'll probably just do the engine swap using an '88 / 89 XJ6 as originally planned. We're not talking about electronics or any of the other problems associated with this entertaining little project; just the subframes.

Please, no need to question why I want to do it; just curious as to whether the subframes' mounting points are the same? I've done other swaps and customs before, so I know the many challenges I'll be getting into. Just want to know at this time if the frames of the two cars are similar enough so that mounting points line up.

Only thinking out loud at this juncture...

Old 06-01-2016, 09:35 PM
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Both sub frames just bolt in with no issues.

Consider swapping it all from a late XJS when they got reliable. I've done it. The XJS was based on the XJC, many dimensions are exactly the same, some are close and some are way off. I took a complete 1995 XJS and swapped almost everything over to a XJ6 coupe. I also used the complete ABS system, all the harnesses, heated seats, power mirrors, powered memory seats, wiring for the lights, bulb failure warning system, complete steering column, instrument cluster, gas gauge anti slosh system, door, key and headlight chime, window wiring and door lock system. The XJS didn't have powered rear windows so I still have to add that in.

It all fits with modifications. This type of endeavor is only for the experienced auto enthusiast but its very doable with patience, some ingenuity and some welding. You have to drill many large holes and mimic the way the wiring is run on the XJS. For example, the brake switch arrangement had to be unbolted from the XJS pedal box and a the XJS mount and switch actuator rod needed to be welded to the Series 2 pedal arm and box box.

The complete HVAC system will fit, wiring harnesses too. Even the sound deadening mat on the transmission tunnel fits with some minor trimming.

I relocated the battery to the trunk using the XJS battery tray and the + battery cable fit perfectly.

There are many many caveats...For example... the HVAC system the rubber boots that connect the blower to the center combination unit are different, the XJ6c series 2/3 boots are used and then it all fits perfectly. For the center HVAC box, the XJS defrost appendage can be removed from the box and the series 2 arrangement simple replaces it.

I was also able to wire up the Series 2/3 wipe motor to the XJS wiper controller so now I have low speed, high speed, variable intermittent, simgle swipe and when you push the button for the washers it automatically swipes 3 times, just like the XJS does. This was the most difficult thing for me figure out.

The HVAC system was the genesis of the swap. After years of poor performance from the converted series 2 system, I thought the up idea to use late XJS stuff which was designed for R134a. Initially I was planning to use the just XJS the evaporator and expansion valve but... I came by a complete XJS with no motor for good price. As I started to swap over HVAC stuff, one thing lead to another and I ended swapping it all.

The complete wiring harnesses, front to back, can be used. The XJS is a wider along the dash where the harness runs, a simple U loop takes up the extra slack. Instead using of the connector boxes on the firewall I had to run the harnesses through the kick panels just like jaguar did on the later XJS so drilling some holes is necessary. For me it's worth it because the late XJS harnesses are brilliantly done. Few connections means greater reliability.

My car was widened in the rear for larger tires and is presently being prepped for paint. It took me a year of working now and then to do the swapping over. Still a few items to tackle...like getting the XJS instrument cluster to look right in the dash. I've spent many nights looking at wiring diagrams. But in the end I will have a thoroughly modern coupe with all the creature comforts and electrical reliability of a 1995 XJS. Pictures soon.

Last edited by icsamerica; 06-01-2016 at 10:01 PM.
Old 06-01-2016, 10:57 PM
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And you do all this in NYC?

Old 06-02-2016, 04:49 AM
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Thank you! That is the info I was looking for and in my wildest dreams, what I was hoping could be done! Haven't yet explored the details or done a lick of research but your info now leads me to believe this project is right up my alley. My fabrication skills are reasonable and I've wanted to build this car since having parked it about 10 yrs ago. Coming up on retirement and plan for this to be my final serious project with plans to use it for lengthy road trips and events. Again, many thanks.
Old 06-05-2016, 01:46 AM
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Tony, build that car and then get in it and go & go & go & go !
Old 06-05-2016, 06:43 AM
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I've 3 projects in the garage which have been on hold due to house construction. After 10 years, the house project is far enough along where I'm gearing up to work on something I enjoy; one of my cars. The coupe will be the quickest one to put back on the road and can't wait to "go & go & go & go".

The purists will cringe but as I don't see the coupe reaching the astronomical values that other classic Jags are, I'm planning on some subtle modifications including the drivetrain and driving it like a fair weather daily driver.
Old 06-05-2016, 09:28 AM
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So, some will cringe?

1. Your car, doe what suits you.

2. From derelict or crusher bound to the road, even if modified. What is wrong there??

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Old 06-06-2016, 05:45 PM
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At some point, the XJS got outer disc brakes, which is even better as you can actually get to them without getting under the car !
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