Jaguar XJS/LS3/6L80E Swap

OK, another one. I have pretty well scoured this site looking for info before choosing to go this way, and as in many things, was unable to find it all in one place. I will TRY to document whatever I run into that is important, hoping to help along anyone with similar aspirations – also good to document it for myself, when several years from now, I have trouble remembering what I did, so rather than my usual scribbled notes stashed “Somewhere” Hope to complete this spring, unforeseen life events notwithstanding.

I will attempt to document any part numbers used, and any critical dimensions or locations. I don’t mind changing things, if it makes sense to do so. No worries with cutting or welding on the car, if it is within my capabilities. I am NOT worried about reversibility – I could buy a couple of stock ones for what I will probably spend on this.

Most importantly, I sure do not know everything – if anyone has any been there, tried that, these are the problems you will have – PLEASE let me know.

I tend to be verbose, so, skip whatever you wish. I will also try to relate what was going through my head with the decisions I make – if only to answer the “Why did you do THAT” question. Further – while I often write quite a bit at once, I will try to split up into manageable posts.

A bit of background info is included in the next few paragraphs – it does influence the decisions I make, and the way I approach things. With a couple of possible exceptions, I do plan to do all of the work myself.

Pictures coming when I start on the car.

ABOUT ME:

Retired, ”kind off”, Income is SS plus a side business, Bright Eyes Dove Release, that brings in a bit of income, although it is not consistent. Not rich by any means, but we (my wife and I) are grateful to be better off than many folks who are hurting. This was a fairly major decision for us. I am pretty good all round – held 9 ASE certs in a past life, excellent composite tech, pretty decent at bodywork. I am a good manual machinist, pretty decent electrically, good fabricator, good gas welding/brazing/silver solder, can kinda run wire, terrible at TIG. I know how to paint, can instruct others – just can’t do it. Have done engine swaps in the past – there are three Fieros outside – did build a complete car, frame and all, in the ‘80’s: But importantly, was GM fo a custom boat builder for 20 years – everything you do is one off, from scratch, and it HAS to work when you get done. So, pretty confident that I can overcome whatever issues I get myself into, but all the same, would rather know going in what I am in for.

One further note: I am British, with an engineering background. Two parts to that – firstly, engineers solve problems – if there is no problem handy to solve, they will cheerfully create one. Secondly, there is a saying regarding British Engineering – it does tend toward somewhat elaborate solutions to problems that turn out to be non- existent. I try to keep this in mind, but sometimes need my chain jerked.

FACILITY:

Residential, double car garage, one side, the one I will be working in is 26’ long, so a bit of room ahead of the car. Other side, I can use, but there is one of the Fiero’s in there up on a 24” stand, no front or rear suspensions, engine or trans. It’s on hold, the XJS comes first, but I could move if I have to. Well lit, concrete floor, but no hoist – only 8 foot ceiling; put a 100K furnace on one wall so good on heat. I also have a shop, one side for wood, one for metal – couple of lathes, couple of mills, bandsaws, small shaper, etc. Oxy-acetylene, wire feed, three phase air compressor, hoists, trans jacks, etc. Anything reasonable, I don’t mind buying.

THE CAR:

1995 XJS convertible, about 125K miles. currently AJ16/ZF trans. Rust free, pretty decent body, interior showing it’s age, but I do have a full set of leather and carpet from Aldrich in England for it – just not fitted yet. PS rack leaking a little, rear subframe bushings tired, otherwise OK. Important thing to note: My wife likes the car. We were heading up to the mountain on the Goldwing when she saw it in a lot, made me turn around to go back. Says it is comfortable for her. For what I am going to spend, I thought pretty hard about other convertibles in the price range of the conversion – Like to keep it under 20K, but not seeing anything that I would want to drive, that did not have it’s own set of potential problems. By “want to drive” – it means convertible, grand touring car, comfortable, still gets a few thumbs up, something you look for an excuse to drive. Oh, yes, and “It’s always an adventure when you take a Jaguar on a road trip”

WHY:

Well, mainly, not getting along real well with GEMS 6. I had a year’s worth of issues when I first got the car, replaced pretty well everything, including ECM and wiring harness out of the car, then all of a sudden, it ran perfectly - for no reason - for five years. Then last spring: back to issues. Be one thing if you could actually access the ECM but apparently, for those couple of “Almost OBDII” years, can’t be fully done without the magic unobtainable OEM Jaguar tool – and it has never set a code. Local Jag shops aren’t really interested – even tried to get a job at one, but I think they saw through the reason for that. Thought about aftermarket ECM, but – I do remember having some power issues – towing a trailer over Loveland pass comes to mind, along with a couple of other instances, so more power would be nice.

I love the powertrain in our XJ - (AJ34 – 6 speed) - even though I had to replace an engine in it - and my first thought was to buy a car and transplant that engine/trans. Quick look at the engine sump/XJS crossmember dispelled that notion, so, regrettably, looked at an LS – hate the idea, but it is a compelling argument. Wife said do it, just make it reliable.

WHAT TO SWAP:

Older SBC was ruled out before even really thinking about them. Driven those – had one in the car I built – OK, no brainer to work on, but SO dated. So, next question, LS or LT. I’ve added power steering to a couple of Fiero’s, don’t really care for the electric PS pumps, prefer hydraulic. LT does not support hydraulic, far more support available for LS, feeling lazy – this is a “Get it Done” project, not a “How hard can I make this” project, LT was an extra 4K, might get another 1 or two mpg, but LS got the nod. Was going to build an engine/trans – but “Get it done”, so bought a GM Connect and Cruise LS3/6L80E package. Might have to tweak TCC lockup parameters, axle ratio, etc, but otherwise, ready to go. Oh, and the Wife said – Don’t mess around – just buy a new one. I am aware that the Speedway You Tube videos say that the 6L80E does not fit – I am also aware that a member here says that it WILL fit – although with no pics – so I took his word, and spent the 4K on a transmission.

HOW TO DO IT:

 

Well that's the road less traveled.

Where does the Erod put the A/C compressor? Do you need A/C in a convertible?

I made my own mounts. I used CTS-V mounts with custom brackets. I figured a pair of mounts for a Cadillac with 556 HP should have the right combination of strength and NVH considerations. They are large and the brackets are nothing fancy, some plate, C-channel and gussets. I've used these CTS-V mount on two projects so far. I originally had Andrews kit but the engine sat way too far forward for my needs. I ended up making my own mount so I could get the engine as low and as far back as possible. Getting the engine low will help you fit the massive 6L80E . For me setting the engine back and low made a big difference in driving dynamics at the edge. When my car had the SBC betwixt the frame rails, it didn't have a dizy cap so could shuv it further back than typical. First I modified Andrews mount to push the engine back an inch but I wanted to go further welded up extension plates and a new transmission mount. This also gave me more room for the steering shaft / header problem. Then when I went from the corvette style SBC mounts that the "kits" use to the CTS-V mount the vibration (NVH) was noticeably reduced.

Now I have an LS and it's low and back too. I used the same CTS-V mounts and made new brackets. It's extremely smooth, just as smooth as the V12 and I know becasue I have one of those two for direct comparison.

I used a C5 corvette serpentine which mounted the compressor very low but right over the motor mount pad on the sub frame. I ended up cantilevering the passenger side motor mount. It's tight but all that weight is low, low low. Safer this way too. If the motor mount completely failed on that side the engine would simply drop about a 1/4 of an inch and the AC compressor would rest on the subframe while supporting the engine. On the driver side, if the motor mount failed the engine would drop about an 1/8 and then manifold would rest and get jammed on the frame rail keeping the manifold away from the steering shaft. I track my car so these are necessary fail safes that have no down sides. The only way to get a no compromise build is to make what you need and I also had to weld up the headers too. That's difficult and by far my lease favorite part, I'm not a good and patient welder but they don't leak.

I have a TKX 5 cog in this LS project but I also have a 6l80E in another vehicle and it's a fantastic automatic transmission. Just the right amount of gears, responsive and no vices.

These Picts will probably make more sense as you get further along.



Right hand side. There is a motor mount hiding in there.

Left hand side.

I do love the Small block Chevy though. It's an icon. Nothing will ever top it in my lifetime, perhaps the LS or GM's new 4 valve v8 but we'll know in 50 years. I finally gave in to the LS cult and I'm glad I did. This LS is my first LS and the learner, it's nothing special, cobbled together from what ever was a good deal on FB market place and it's extremely smooth and powerful. Z06 cam, 6.0 LQ4 block, 317 heads. truck manifold. Cost about 3K total and I'm in to the trans / clutch setup for a bit more.
Here's a vid of my old SBC project, at some point you can see me run down a supercharged LS1 corvette. He got heat soaked and in earlier laps he was walking away from my on the straights.

 

Thanks for the pics - I am sure I will appreciate them, as you said.
This is not an E-rod, just the standard package. Washington State gave up on emissions inspections a year or two ago, anyway it is grandfathered out of state compliance, so no need for me to spend more for the E-rod.


This is about as far as I got today. Wife is out of town, so I get dove duty.

Tes, you do need A/C in a convertible. Kinda like a motorcycle, some days it is just TOO hot - you either suffer, disappear to the beach for the day, and don't come home until it is cooled off, or put the top up and use the A/C.FIRST PURCHASES:

First off was the Connect and Cruise package – LS3/6L80E, 430HP, bought the 2400 stall converter. I would have liked a lower stall speed, but my understanding (Possibly wrong) is that I can command TCC lockup at a quite low engine load, and release the lockup as the engine load increases. The transmission does come with programming software. Paid $13,700 from Pace Performance; with a $500 GM rebate. Nice guys to deal with – they were one of the few who responded promptly to my initial questions. Ordered last September, delivered in December, been trying to finish other projects to give me a (mostly) clear two months to work on this. Depends a bit on Dove Releases – supposed to be the dead time of year, but both January and February had about 10 for the month. I don’t get much other work done on a Dove Release day.

Pulled the car into the garage a month ago, pulled the hood, jacked it up, looked around a bit. Had a couple of other projects to finish before I can start on this, so it was just a quick once over with a tape measure. It APPEARS that the 6L80 will fit the tunnel, and the block/bellhousing part line can stay in the same longitudinal position. We’ll see – I don’t mind a little tunnel work, but not really wanting to replace the whole thing. Anyway, assuming it will fit.

 

Subscribed!

 

In your scenario the 2400 should be fine. The XJS is lighter than most cars that engine package would end up in so the higher stall wont present as much. Also Gear 1 and 2 are very short on the 6L80e, combine that with the 3.54 diff and you will still have a very responsive combo from the dig. Then if you lockup the converter in cruise (3rd and up) you will have excellent throttle response. It's not going to be anything like a 2400 stall an older 3 or 4 speed.

The trans is going to be tight in the back because the tunnel takes a dive at the back end where the 6L80e is still tall. It will all depend how far back you want to set the package and how low you can go.

The A/C in my convertible hasn't worked for years. It's been strictly a morning / evening cruiser. Maybe I should give it a try. LOL.

 

The engine came with what looks to be the "Muscle Car" pan, frequently sold on ebay and by normal vendors. I believe it is p/n 19212593 - and depending upon where the engine winds up, it looks like it will work - so that is on ignore until I try the engine in there.
I bought the Corvette engine mount stands, 16349964/5, new take offs, paid #110 for both. Bought ne hydraulic mounts, 15254700, paid the money for OEM mounts - too much opportunity for aftermarket to cheat here, in my opinion. Transmission mount - I bought the Camaro mount for the same powertrain, 10448683. First glance is the mounts will work best reversed, with a cantilever mount plate curling back around the rack tower.
Front end - I am not really looking at a show car here, don't really need - or want to afford - fancy billet systems. The Chevrolet Performance Corvetted system, 19155067 looked to work well, one was on ebay at the old price, so I stuck my head out and bought it. By all accounts, it will work with the harmonic balancer and water pump already on the engine - almost like someone had planned it, A/C compressor, low on right side, bottom is at crank c/l, outside is 13" out from crank c/l. P/s is mid mount left side, alternator, high left side.



Pulled the engine - left transmission in - wanted to record driveline angles before I pull it. Only thing of note pulling it was a bellhousing bolt that galled. One of the top ones, that goes through the bellhousing into the block. Worked it for a while, finally broke it off. Other thing was a ring dowel that was severely corroded in place. - like a couple of trips under the car, to check AGAIN that I had not missed a bolt. Finally took to one of the BIG pry bars - like 48" heat treated 2" deep kind of thing, it still took quite a bit to seperate them. Oh, and I had to fix the engine hoist, because I had cut 18" off of the legs, when I was installing granite by myself in the kitchen, and needed it back for this job.


Made a stand for the engine, tucked it away in a corner, rolled underneath the car, and thought about exhaust for a while, and pretty well called it a night. Figure to drop the transmission out tomorrow, might also pull the front bumper cover - easier access for the engine hoist where the LS will hopefully go. Friday is maybe halfway decent weather, so will roll the car outside, and pressure wash the engine bay.

I really wanted to use the Z06 exhaust manifolds - plus they are pretty cheap - but it looks like the rack tower will kill that. There is maybe room to insert a small intermediate shaft, gain an inch or so, but not too muck. I was always brought up to believe that 30 degrees was the max for a steering shaft U joint, have not had an issue using that number - but I'm probably getting well ahead of myself. Next choice is maybe the Speedway "Tru-Ram" manifolds https://www.speedwaymotors.com/Tru-R...hed,53711.html Look to fit, but they have a ridiculous (to my mind) 3" outlet. Still looking at options.

 

I'm following this was interest. Are you planning on upgrading to more performance oriented wheels/tires? Asking because before my XJS I had a supercharged XKR that was rated at 420HP. It was an obscene amount of power but it had the suspension and wheels/tires to deal with it. I think the back tires were something like 275/35-19's.
I'm curious to see if you think the rear cage can handle 430HP - specifically the mounts that hold the cage in place.

I'm also curious to find out if the engine can support OBD2 readers. When I put a GM v6 in my MGB I made sure to hook up the ALDL. It only supports OBD1.5 but it's still helpful to get troubleshooting data.

Good luck! The Connect and Cruise is a great kit and I am going to be super envious of the 6-speed transmission.

 

The intermingling of the motor mount, steering shaft, exhaust manifold on the driver is challenging. On the passenger (drinkers) side, the motor mount, exhaust down pipe a/c compressor and a/c compressor lines and frame rail all want to occupy the same space. Based on having just done this I don think those speedway manifolds will work. Installed as designed they will send the down pipe right into the steering shaft on the drivers side, Reversed or swapped (side to side) they will send the down pipe right into the motor mount / inner tie-rod area. As you said the 3 inch collector will difficult to manage too. Be sure to check speedways return policy before you order. When I was doing this I tried about 10 different off the shelf manifolds and nothing worked. That was during lockdown so choices and stock were very limited, I hope you have better luck that me but I have a few non-negotiables so I can pass tech at the track. There are certain things they look for on swaps, including how the engine is mounted and steering shaft clearance. Creative steering shafts are an absolute non-starter for tech inspection.

I really didn't want to weld up my own manifolds but it was the only no compromise way and doing so was miserable for me but it had to be done. I hope you fare better, especially in this regard,

I've written about this extensively but your rear IRS will want to wind up and bang it's snout on the floor pan ripping up your bushings in the process, That's IF you manage to get enough traction to put down the power, And for some reason these cars launch crook'ed when mashing the go pedal. In order to solve these problem the IRS will need extensive work if you care about this. Once you get north of 400 HP basic bracing plates and uprated bushings hit their limits IF you have traction. I copied a-lot of what Aston Martin did on the DB7. Traction / good tires + wiggly IRS + 400HP = dangerous shitbox but some people find dangerous living fun.

 

Pulled the driveline, front chunks of the exhaust, transmission, oil, P/S and cooler lines. Took a closer look at the transmissions.

6L80E and the ZF on the bench, output shafts at the same height.

The 6L80 is about the same length from bellhousing flange to the tailshaft housing flange, it is about 1 1/2" taller than the ZF.

Top view
There was seemingly plenty of room to the sides, at the rear of the tunnel. Height may be an issue, BUT


With the foam padding that was above the ZF, looks pretty close. It is going to hang a little lower. It appeared as if the transmission pan on the ZF was about 1 1/4" above the coil spring housing on the original rear crossmember - that was the lowest thing on the car. I have ordered a shallower transmission pan, was original equipment on a 2008/9 Pontiac G8, p/n is 24239528, takes about 1 1/4" off of the pan that was supplied with the transmission. It does need it's own filter, but that is available locally. For whatever reason, there is a "Shallow Transmission Oil Pan Kit", GM p/n 19418242 - but all the usual suspects want $220.00 for it - includes the pan, gasket and filter - but the filter and gasket is a normal $20.00 item, and I paid $38.00 shipped for the pan through Amazon, GM parts warehouses were in line with that price.

Tomorrow, plan to pull the car outside, pressure wash the engine bay and front crossmember. I will pull the car back in, get ti set on four stands, level enough to use the floor as a reference. Thinking I will make a quick foam reference template of the transmission, and try it first. Then hand the engine in there, try the foam trans again, then see how the package will fit..


I did go ahead and pull the bumper cover and bumper beam, easier access with the hoist to get the engine to the back of the bay.

 

I understand the "occupy the same space scenario - for such a big engine bay, it all come together at the back end there. Got ideas running around, but until I see the engine sitting in there next week, they are just ideas. Good thing is, no inspections - not to say that I would want anything sketchy - most of the time I tend to over-engineer.
At this point, I am not too worried about the rear suspension, other than re-bush everything, change to 2.88 gears. I would like to try to find/adapt/build some form of air suspension unit for at least a pair of the rear shocks. I do tow a little camp trailer - about 1500 lbs, 200 lbs tongue weight usually has it pretty stable - but it does sag the back end a little, and like to be able to level it out.
Reason for not worrying too much - I use this pretty well as a "Grand Touring" car. I find that the car usually tells me how fast to drive. Yes, I want to make time on long road trips - but I also pull over for people to pass on back country roads. I get real impatient with slow drivers in the Fieros - in the XJS I sometimes AM the slow driver. I do have an XJ (X358), thinking I've used full throttle maybe five times in the last five years. NOt so sure that I have used full throttle that much on the XJS - with the singular exception of 10,000 feet passes with a trailer on - and was certainly nowhere near 232HP at that point. If it needs fixing, I will - but I would have bought a smaller engine if it was available.

Yes, the Connect and Cruise does support OBDII, although they don't really seem to push it - the diagnostic port is on a short jumper off of the ECM, but I will probably wire it to my existing port.

Mike

 

[QUOTE=fast40driver;2503038]
At this point, I am not too worried about the rear suspension, other than re-bush everything, change to 2.88 gears.

I think it is a mistake to change to 2.88 with the 6l80. That transmission has .67 ratio in 6th and will give you plenty of overdrive with the 3.54 ratio that I believe you have now. I have a chevy pickup with that trans and 3.42 axle and it turns about 1600 rpm at 70 mph. Even with shorter tires you probably will be under 2000 rpm at highway speed. Your choice, but I'd leave the rear axle alone. If you really don't like it, you can always change the rear ratio later.

I now see you have another thread on the gear ratio, and have already considered everything I said. Good luck with your build.

 

Mostly just going with pictures here - stuck a broken drill bit through my thumb, not so much into typing.
Wife came home from FL Friday - her mother just passed - had to work Saturday, friends over Sunday, so just a bit of Sunday and today on the car.

Right side

Left side

Back - Bellhousing face is about 2 3/4" forward of firewall.

Bottom, with transmission mockup in place

Left side from bottom

Right side from bottom

Lots of room in front

Going to need a little tunnel work. About an inch wider at the back, plywood is the top of the trans, still would like just a little higher. Guessing I can press out the sides, probably need to cut and weld the top.

Got tired of the engine crane bleeding down, so put a couple of brackets on the ceiling this morning, and hung it from a manual chain hoist - pretty stable now.. Corvette mount stands are reversed side to side - moves them back about an inch, to clear the rack tower. Going to cantilever mounts from the crossmember, plus a couple of angle gussets down from the rack brackets. Might add a tension strap from the top of the original mount pad, but really won't need it. Feeling lazy, will use 6061 - nothing in my scrap, so will need to buy - I will see if I can find some plate rems. 5/8" would be ideal, 3/4 overkill, at 1/2", OK but I will NEED the brackets. I should see about 0.055" deflection at 2G load with 5/8" plate - but max fiber stress is only about 10,000 psi, so lots of wiggle room - that's without the rack brackets, and without a tension strap.. Trans mount looks stupid simple - flat piece of plate, with maybe a couple of spacers.

Got to work tomorrow, and just booked Friday, so not the clear week I anticipated.

 

Oh, I've done the broken drill bit through the thumb thing, extremely painful. A few months ago I had one go right through my thumb cuticle. That was the end of cheap drills for me, Now is only made in USA drills. No regrets and so far no broken bits. My wallet is a bit lighter but my thumbs are intact, Lowes sells Cle-line drills and they are amazing,

She's in there tight, You've your work cut out for you. Engine position matters but yours is a cruiser not a track car so moving the engine a bit forward wont matter all that much in the end if it helps get it done. You've got to decide how much you want to torture yourself. How much room between the rack and oil pan? This project will be infinitely easier if you move the engine forward a few inches and perhaps switch to an A/C compressor that is mounted higher. That will allow you to make a simple mount for the drinker side in the Jaguar OE location on the subframe. Moving a 20lb A/C compressor up 12 inches isn't going to matter on a street car one bit but will make this project 100% easier. On the driver side you'll need some space for that rearward exhaust port, its tight back there as you can see but it will be even tighter when you put a exhaust manifold on it.

Go to Homedepot or any store that sells batteries and has shopping carts. Put the battery in the basket over the front wheels of the shopping cart and see how the cart moves. Then move the battery back 3 inches, see how it moves, It will be better but all not that much. Now move the battery to the middle of the cart and then to the back, This will demonstrate how weight location effects handling and motion dynamics at a very simple and basic level that does scale up. Bottom line, if you're not tracking the car the marginal distance of 3 to 6 inches of engine location wont matter. Have you seen Audi's, I have an S8, the WHOLE engine is forward of the front wheels, car handles fine on the street, quite nice with a bit of safe under steer and plow. When pushed with high cornering forces and high speeds into triple digits it start to matter, your not doing that and zero chance your engine end up completely in-front of the front axle.

 

I am pretty familiar with the Audi - owned an A8 D2 - great car - except when it came time to change the fuel pump. I am envious of your S8 - daughter's significant other has an S4 - that's quite a car as well.

I am really not worried about the engine position as far as the handling goes - figure I will gain, no matter what. I am interested in the ease of installation, (relatively), and as I mentioned, was quite interested in using the hydraulic mounts. I had not considered the CTS - V mounts, but realistically - at least to me - the Corvette mounts are useable. I reversed the stands on the block, with the engine bellhousing flange about 2 1/2" forward of the firewall, the mount nestles right behind the rack tower. I can't go up too much, mount stand would hit the steering shaft, and also, trans bellhousing would hit the firewall. Forward - mount runs into the rack tower, so really pretty happy with where it is. Plenty of hood clearance, pan is just about even with the bottom of the X brace. The little notch for the A/C line connection really does not worry me at all. If I do worry after I do it, I will Bridge over the top with some bar stock - probably use Cherry Q or similar structural rivets.

Transmission - I messed about with a porta power on the tunnel, gave up, took about 5 minutes with a 5 lb sledge to get plenty of clearance. I will try to smooth it a little with a planishing air hammer, and a backing block - but some dynamat inside, undercoat outside, it will be just fine. I made up a mount plate out of 3/8 6061, needed to cut out for the mount, and add a little "Bridge" across it, but it came out fine. Yoke is about 1.8" from the driveshaft tunnel, high as I could get it, didn't want to get into that. I will gain a little clearance - I have a 13330 yoke in there right now, Amazon sent the wrong one. I put the real trans in the car, bolted up to engine, and installed the mount..

Top of mount plate


Bottom of mount plate


Mount installed. Shorter transmission pan coming.

You are right about exhaust - I have not been able to find a manifold that will work, so regrettably, will need to build something. Ordering some flanges with pre-welded stubs from ebay might have to cut the back ones off - but hopefully it's a big step toward not warping the flanges.

Tomorrow, on to engine mounts. Stopped by the remnant store yesterday, they did have some 1'' plate, almost the right width, and the right length - kinda overkill, but oh well. As was said, on a road car, an extra 10 lbs won't kill me. Rather do the W.O. than the Chapman on this, anyway.

Cheers,

Mike

 

That plate is nice and closing up the trans tunnel like that will add a lot of rigidity to the chassis which is lacking. In the later years Jag installed a steel plate that was about 28 inches long to close the tunnel. Your car should have that plate. Another great trick to reinforce the chassis is a tie bar that connects the two front jack points, they unscrew and a bar can be made to transverse the tunnel there too. When you weld up your exhaust leave some room for it becasue it will make a very noticeable difference

Sounds like you are on the right path with the headers, if I had to do it over again, I'd get a scrap LS head on FB or Ebay and do the final weld with the flange bolted to a scrap head to try to manage the warping.

 

Started like usual, with a couple of bits of cardboard, cut to about the right size. Transferred those to 1" 6061 plate, and rough cut. I clamped them to the front crossmember, cut some pieces of 3/4 x 3/4 steel, drilled and counterbored for 1/4 20 SHCS, radiused one corner to fit against the crossmember, then drilled and tapped the base plates through the crossmember into the base plates. Boulted them in place, then made a couple of risers for te engine mounts. Trial fit the engine once again, and scribed the risers to the mount plates.

At that point, it seemed easier to pull the crossmember rather that work in the car, so - removed the crossmember, disassembled the suspension - was going to do that anyway - and put it on a table.I pulled the rack, cut off the small gussets at the base of each rack side mount plate. I cut four pieces of angle - secured to the base plate with SHCS's, picked up the rack mount bolts, and also a couple of additional drilled holes on each side.plate.Trimmed the angles for rack clearance, needed to cut a small hole in the driver's side base plate to clear the rack. With the rack mounted, I looked to put a tension plate down from the original engine mount pads. It was a little tight in a straight line, so added a 1/4" spacer to the top of the original mount pad - this raised up the plate a little, and also extended the support for the bend of the tension plate aft a little. Extending the plate bottom bend aft, right to the bolt line on the base plate/risers gained me just enough clearance for the rack boot - looks like through it's full range of motion, but won't be fully sure until the suspension is fully assembled. Screwed everything together, gave it a quick clean up, but no real finish for anything until the last time together.

Baseplates on crossmember, spacers on mount pads, angle brackets on rack mounts.

Rack in place

Risers, mounts and tension plates added

Was trying to go as high as I could with the engine, for transmission pan clearance. Other option was further back, which put me into the thermal expansion valve for the AC. Gotta draw a line somewhere, will drop the engine a little, easy to take metal off.

This is the real transmission, from the front, in pretty much it's running position. Back mount is connected.

OK, I trimmed those mount risers by .250, had some clearance with the rack tower - probably not RUNNING clearance, but wanted to re-install and see how things looked. It was kinda late on a long day, and I screwed up. With half a brain, I would have tried the engine on the mounts out of the car, but had the Crossmember back in and engine half way in before I thought about it. It didn't quite bolt up - wasn't really surprised, I had 1/2" holes for 12mm mount bolts - thats damn near .030" slop, right - but I had kinda hoped. So, next thing is to slot the mount holes just a little - hoping to get back to it Saturday.

Only three real hiccups on the mounts that were unexpected -
I broke a tap in one base plate, for no reason, COULD'NT get it out, and I don't have an EDM, so had to fix the hard way - cut a plug out with a small hole saw, drilled to the correct size, tapped the hole, locktiterd in a threaded aluminum plug, faced it off flush, and drilled and tapped that.for the bolt.

I screwed up a bled on one of the tension plate - the remnant store had no more 3/16" plate, so had to take a bit of 1/4", and mill it down to 3/16" - couldn't get the bend radius I wanted on 1/4", especially not with the little press I have.

Lastely, the front subframe mounts. Bolts came out easily, mounts too, tossed away the old ones, couple of days later, went to install the new. I did not realize that there was a separate bushing inside the inner bushing of the mount. Quick look on the web, Jaguar wants $60.00 each - no way, I can make bushings. Headed out to do just that, when I remembered the Garbage man had yet to come. Was able to retrieve the old ones from the trash, got the bushings, and installed.

You guys probably know all this - I didn't until I unwrapped the new bushing.

All in all, the mounts are solid as anything to the subframe. As far as the engine weight goes, not a worry in the world at 3G it's only 850 lbs per side or so. Torque load is something else again. 420 ft lbs x approx 4:1 first gear ratio is 1680 ft lbs, at 8" is about 2500 lbs, plus weight of 300 lbs is about 2800 lbs load. Nothing much there, a single 1/4" bolt will support 5000 lbs (with fine print), big question is resolving the torque load into the subframe. I'm not smart enough to figure out what will be taken out by the road wheels and springs, and what will resolve into the car frame. In the end, not expecting a problem, and we are well toward the "WO" end of the spectrum, as opposed to the Chapman.

Hope to be able to work on it some Saturday.

 

What are you using to cut the 1" 6061? They turned out looking like works of art.

Just an observation from my experience - dropping the steering rack is one of the steps when I need to work on the exhaust down pipes or get to the starter. If your steering rack mount is part of the engine mount, are you going to be able to drop the rack? Granted with the V8 you'll have a different exhaust down pipe configuration than stock, but something to consider.

 

The Alu work is art. No question about that but I think this is a classic case of when we only have a hammer everything looks like a nail. My concern is the cantilevered mounts seems about 12 inches rear-ward of rear subframe mount. This will want to rotate and pull the subframe downward since it's vertically hinged around the front mounts and the downward force will be far behind the center line of the spring and suspension axis. I have no idea what the real world implications of this are but it doesn't seem good and it's not a experiment I'd be willing to conduct.

In the OE application the engine mount are a bit forward of the rear most subframe mount which reduces the downward pull on the rearward mounts, We know this is the case becasue as a vector problem the forward motion of the car whilst hitting road imperfections tends to wear out the front most subframe mounts first. That much cantilever may alter that vector problem in an unpredictable way, You're really asking those two 3/8 bolts that hang the rear subframe to do a lot of heavy lifting. Jag Kind'a knew this was an issue so on later iterations (XJ40 and X300) the rear most subframe mount moved much further back and increased in size greatly.

I also see the driver side mount exacerbating the exhaust manifold problem and the mount is right were a center dump exhaust pipe will want to be.

This project is getting myopic and needs a rethink. The way the engine mounts is too far a-field and unnecessary. It makes rack servicing jobs such as an inner tie rod replacement an engine out job. Did you do design work at Farrari or BMW in the 2000's ? On the driver side a basic L shaped mount bracket can be fabbed up to put the LS mount dead center on the OE location avoiding unknow downward stress on the rear subframe mount while also making far more room for the exhaust manifold exit pipe. Same goes for the passenger side if you'd be willing to move the A/C compressor up 4 to 6 inch's and judging by the work exhibited so far, making a new A/C compressor bracket would be a walk-in-the-park. Other than the A/C compressor interference there is ZERO downside to using OE location for the motor mounts on any of these engine swap projects.

Personally speaking, when it comes to life and mechanicals, simple is always better. I've used the KISS principle to great advantage and It works.
https://en.wikipedia.org/wiki/KISS_principle

 

Aluminum - cut with a bandsaw - I do have a metal bandsaw, lucky there, just cut to size, cleaned up with a flap wheel and belt sander. It will actually cut OK with a circular saw, and pretty sure I could do it with a wood band saw and cutting fluid..

I would be worried about the integrity of the rear mounts also, if the engine were weight and torque load were being carried by them. What I keep having trouble with stress wise is the the road wheels carry the weight and load of the engine to the subframe, subframe carries the engine loads, and also carries the weight of the car. Simplistically, the downward load on the engine mounts will translate into an upward load at the front subframe mounts, rotating around the road wheels. Likewise, the engine torque load should resolve itself across the road wheels, not through the frame or subframe mounts. Fly in the ointment, though, is the anti roll bar that is frame mounted - plus the weight distribution and frame flex of the car itself are pretty well unknowns. On the surface level, the loads on the subframe will not be that high, but the long-term durability is up in the air. Tried pretty hard to distribute the loads around the "torque tube" of the subframe, to avoid point loading any one section. The long term durability is an unknown.

I do have a hole for the exhaust, that I think will work. More worried about heat transfer from the rear ports than anything. I was not going to try for long tube headers - still really do not need that much HP.

I was, however, looking with interest at the read end support tubes icsamerica used - lost thread now, but sure I can find it again.

Yes, I will be able to get the rack out - but not that easily. Been a mechanic off and on for 50 years now, usually found that once you dive in, things go far faster than you think. It is a ZF rack, so ahead there. I understand your concerns - I have them also - but usually, 905 of what I do works out OK, 10% will bomb, and I will have to start also. I would also re-iterate that I, as do other British engineer types - tend toward elaborate solutions - just look at the Jaguar itself.

I did know from the start the easy way - and the cheap way - was to buy a kit. In some ways, I guess, I LIKE to do different. I don't think I can do better than a factory engineered car - but it will be MY car, warts and all.. Again, if I bomb, I will re -do as needed. Right now, I am only in the mounts for about $130.00 in aluminum, and $40.00 in fasteners - plus of course, a few days of time. I realize that as I move forward, things get far more locked in stone, and harder to change, but so far, coming together OK - in my head.

I do, however, listen to all you say, it is by no means wasted, it rattles around in my head as possible solutions, or other avenues to follow.. Thanks for the comments.

 

Here is an picture of the OE setup. Notice how the motor mount (weight Point) is in line with the center line of the spring. I believe this is important for proper load bearing and road going dynamics