So I've gone just a "LITTLE OVERBOARD"....I bought a nice/not perfect 90 Convertible and am getting it in shape. Then I bought an 89 coupe parts car...has paid off in many good parts. Finally I acquired a 92 Face-lift (FL) Coupe. All are 5.3L V12s, and all are white with tan interior. I've learned FL V-12 coupes are rare. Only 1199 5.3L black bumper, and 700 plastic covered (fat bumper) 6L coupes built....wow, out of 115K total XJSs. The car has been modified with Mega-Squirt Ignition/Injection computer and twin 6-pack coils. (I have all the stock Marelli parts.) It runs but is missing on 2 coils per 6 pack--meaning only 8 cylinders are firing. The guy who built the system says it's the Mega-Squirt amplifiers; he's is coming to help next week. The bad news is he says it has a burned exhaust valve, based on his analysis when he built the system for the PO. It doesn't have any rattle like a dropped valve seat. So by next week I'll be able to hear it run on all 12 or 11..haha. I was able to get the parts car running but not great. I have yet to do a compression check; but if it passes, I could just swap out the engines. If not, then what? The 92 has some rust around the front screen, and under the wings forward of the door jams. I guess the drains got plugged up. But otherwise it's pretty solid, floors, rockers etc. (Sat outside in Florida rain and Merritt Island salt air...not northern road salt damage.) I have to make a personal decision as whether to sell it or fix it. (My plate is quite full with other projects, but I can just put it in the corner for a year or so...however; at 65, I'm not getting any younger..haha). If both engines need work, my Bench Racing dreams would be to purchase a crashed late model Jag with a 5.0SC engine and auto box to make a Super Coupe. Or a Chevy LS............ NOOOTTTT.......just kidding there. Or I have to find someone with a head jacking plate and fix the bad valve (if that's really what's the problem). If I take the sane approach I'll sell it, but not on Craig's list. It's not a POS, it's rare, and it's perfectly suitable to be restored. I want someone who loves these cars and appreciates the rarity of FL models (which IMO is a very pretty car). I've seen the rusty hulks you guys in Europe have rescued...this is no where near that bad. So I'd really like to hear from the friends I've made here...your opinions are welcome. If anyone is interested to purchase...the price will be very reasonable to the guy who loves this model. PS anything it needs that's on the parts car, including the engine would go with it. BTW the TH400 trans was overhauled so it's suppose to be good. The top surfaces were re-painted and are faded again...sides are original paint in acceptable condition. Interior good, wood nice, leather drivers seat good, passenger got more sun and has some cracks, headliner very nice, carpet good. Tires are shot, brakes okay, rear calipers not leaking but rotors are thin. Oh, and the parts car has the quad headlights which personally I like better, and a good upper bumper finisher. You can see the electric fan mod I made. The CATS and smog equipment/pump has been removed and a GM 130 AMP alternator fitted. (All orig parts available/go with)

 

 

Mine shows 84K miles. The PO spent many thousands on the car, but when the Mega-Squirt acted up he just gave up in total frustration....should be able to fix it, but I can put the stock Marelli back on, however I'd have to make up a harness. I bought it for the custom fit twin electric fan unit which he claimed cost $600. So I'm not too deep into it cost wise. But it's too nice and rare for a parts car. Where are you located?

 

 

I'm interested in this rust spot on driver-side rear panel just ahead of the rear fender...my paint has bubbled slightly there. At least its reassuring we all have the exact same problems haha.

 

Well that one has me a bit concerned, I don't know if it's accessible from inside after removing all the interior panels. PS, my convertible has a spot showing in the same place. I didn't take a pic of the rust under the wings and screen area, but that has me concerned as well. From a "related post" from 2013 that popped up I see the front windscreens are NLA, and if it's got to come out, it will be a harrowing experience. First I have to figure out how to get the SS trim off and see how it looks.

 

Hmm, one thing I've taken to doing as a preventative measure is taking corroseal on a toothbrush and getting under the bubbly paint abit. It's a marine industrial rust converter, then I patch with plastic paint clearcoat spray to skin over the area.

As for the windshield that whole drain system is awful, dripping down the paint up and around down some rails and behind fender panels. I sealed my post area with sprayfoam then black rubberized coating to 'cap' the portion hiding just behind the top of chrome trim, can't see anything unless your looming right over it. No issues in 2 years the water just blows off when you get rolling.

Makes for a good temp fix until theres time for a bodyshop.

 

So you'd like to do the practically impossible (5.0SC), and hate on the possible (LS conversion) . Lots of Flawed thinking in your post. Dont hate on LS conversions. They make the car better and can be done very quickly.

The desirable facelift coupe is the 6.0 V12 with the 4l80e. The 1/2 facelift coupe are not necessarily more preferential than any other early v12 coupe. Someone may want one but With the 5.3 engine, TH400 and the clunky bumpers they are just odd at this point. Some people like odd though. Additionally with a poor running engine, someone's idea of a one off ignition system and rust bleeding through seams, what you have is a... parts car.

 

Ouch. Just a parts car? I agree the 6L with the 4L80E is more desirable. As for the 5.0SC conversion; assuming it would physically fit, I imagine the electronics would be a nightmare. But if a complete engine and trans management harness was swapped in don't you think it's doable? I'm not berating an LS conversion. After all I have the 1964 2 door altered wheelbase S-Type that I put a pushrod SBC 350 in seen here:
https://www.jaguarforums.com/forum/m...1/#post1822025
The LS has lots of aftermarket support and would be easier; plus a 4L65E or manual box is more feasible. And it wouldn't need the super charger for a nice increase in hp if the 430HP LS3 was used. Like I said...Bench Racing at this point.....first to test the existing engine after sorting the Mega-squirt amplifiers.
PS per your profile you don't have an XJS, so not sure your assessment about it only being a parts car is fair or accurate. I have a 89 coupe that is definitely a rusty parts car...this one, the 92, deserves fixing up....albeit maybe not a wise financial move. Anyway, thanks for your opinion.

 

i would certainly try to get it running right on the mega squirt first. mega squirt is a good system but how well it works will depend a lot on the installer. if you can get that sorted out and you don't have a burnt valve could certainly be a good car. as far as it being rare. i think its a bit more of a odd duck than a desirable rarity. i would say the value would be about the same as any other 5.3 th400 car of the same condition, if it were a 6.0 4l60 it would probably be worth a little more

 

i put a sbc in mine lt4 4 bolt main engine that made 400hp N/A and then dropped a small roots style supercharger on it. should be pushing well over 500hp at the tires now and i don't have a ton of money in it. far less than you would have in it trying to make that power with a jag engine, if horsepower is what your after sbc swap is the way to go. LS would be better but you can make a lot of power cheap with a old small block as well although if going with a pre ls at least use a later core 1pc rear main seal factory roller cam block. i happened to have a core engine laying around when i did my swap.

 

Ezrider...Ha I was looking at your latest post and video when you commented here. My seemingly "knock" against a pushrod Chevy is that it's a common swap.
Powerful and Cost effective but not "different" from lots of other Jags that have been converted. If the car was being built by a Top Tier professional outfit with a mega-budget; I think they would use a Jag power train. I hope one of the two V12s I have is sound...for sure!! But if not, is it cost effective to rebuild one...I guess not. Besides, I have the 90 V12 Convert. Not sure I want another. Having said all that; given the time and resources, my rank order would be a Jag 5.0SC 1st, 4.2SC 2nd, LS3 3rd, pushrod 383 4th. BUT if having a manual box becomes a strong desire' I would shuffle those to an LS or 383. Again, inviting opinions at this point. icsameica says its a parts car. Without a good engine he is probably correct. I thought there was a greater desire for the 1st series Face Lift coupes. Hell the front wind screen, which is NLA for FL coupes, is probably almost worth what I paid for the car...$800 USD. Let's here from some more XJS Lovers out there.

I have a factory roller 1pc rear main in my S-Type with an LT1 cam grind and 600 vac holley, 5 spd world class borg warner from a V-8 camaro, XJS 2.88 rear.

 

i wouldn't swap one with a stock chevy engine a stock late sbc makes likes like 260ish depending on exactly what you have a little higher on a ls. makes no sense to swap at those power levels, jag engine is fiddly but there nice engines. however swapping one just open up so many other options, speed parts for a sbc or ls there plentiful and cheap. cam shaft heads and your making good power. aftermarket rods cranks pistons blocks heads enough camshaft grinds to make your head spin already sitting on a shelf somewhere and all that stuff would be custom 1 off stuff on a jag engine. also going sbc opens up a lot of stick shift options for transmissions as well.

getting a 5.0sc in one could be a pretty big undertaking. i haven't looked at one with the eyes of swapping one but assuming you get it in the car mounted decent and everything plumbed your going to need a wiering harness from the donor car spend hours studying pinouts get it all wired and once all that is done you may need to get the computer custom re flashed to ignore theft deterrent or other body control systems that are no longer present. i know iv had to do this on some other swaps that iv done that retained the factory fuel injection but it was all more common stuff and theirs people that already have files wrote that solve these problems i doubt anyone has done this for the 5.0sc engine yet. (i could be wrong haven't looked) doing odd ball swaps is certainly cool and different. in the end you want the swap to be done well and function properly. without a spaghetti mess under the hood and all kinds of random issues.

i wouldn't give up on the stock engine just yet, being its still a v12 car i would try to patch the v12 up first. or at least make a through diagnosis. iv bought many cars over the years where i was told it had one major issue or another and after dragging it home found that it was a simple problem and it was improperly diagnosed.

i would say the odd combination doesn't necessarily make it a more desirable car, given its current condition i would say its a really nice parts car, could certainly be fixed up nice, but would cost about as much to fix up as what you can buy a nice car for. if you can get it running and driving right with just some fiddling and not much money might put it back into that worth saving category.

if you want to do something else with it me personally i wouldn't feel bad about using that car as lets face it if that thing sits around outside without a few of the body issues being addressed for a few more years it will most defiantly be a parts car.

there is still a lot of them out there in nice shape without a very large group of buyers for them right now, if the buyers market increases or the number of nice cars for sale decreases there will probably start being more cars like yours being saved but right now its just not that cost effective when there are nicer cars for sale for reasonable money out there.

 

I agree on a stock sbc engine swap...not worth it. You are probably right on the assessment ... being a parts car in its present state. I will hope for the engine to be okay internally. How do you "burn" an exhaust valve anyway? Then there is the rust under the screen and wings. I have to pull off the SS screen trim to see how bad...not sure how to get it off yet. The car won't sit outside under my care; it rains a lot here despite being called the "Sunshine State". I let a 52 Desoto business coupe sit outside---totally rotted it out (but someone still bought it). I guess I am giving the car an emotional assessment, thinking it's rare and how much I prefer the facelift changes (on a coupe anyway), vs looking at it rationally. Too bad they aren't appreciated more; but then they wouldn't be so cheap.

 

Just planning ahead should the need arise. Does anyone know of anyone or shop in the US that has a head jacking plate for rent?
Like a Merida in these videos:

https://www.youtube.com/watch?v=WT3ofc-qtaQ

https://www.youtube.com/watch?v=Mqrp29BKwv8

 

Got the Mega Squirt tuner to fix the issues with the 92 Coupe. Good news is He got it all working. Bad news is there may be a couple of dead cylinders. Compression check in order. But he said he remembers it had some "burned valves". Compression check on the parts car engine is next. The injectors are all clicking, but on some of holes it makes no difference when I disconnect the injector. SO either some are clogged/not flowing or there is other issues...maybe internal. More work to be done.

 

awesome, having the mega squirt working properly can certainly give you a bit more flexibility in the future. hopefully your get the dead holes worked out. worst case if you have a good head on your parts car you can swap them out.

 

If you need a few spare injectors PM me I have a bag full. They havn't been ultrasonically cleaned but hey a walmart jewelry parts cleaner and cleaning solvent work just as well.

Sometimed its just the filter basket inside the injector is cemented with crud. There are kits out there for bosch injectors to.

 

Update on this thread. I couldn't get the engine to run on all cylinders. It may be a few none working injectors but they were "clicking"; though that doesn't mean they were passing gas. When the Mega Squirt tuner worked on it he said they believed there may be some burned valves (back when the PO had it but parked it). So I did a compression test; after 3 revolutions the pressure was 175psi on 2, and 185-205 on the rest. Did not do a leakdown at this time. So would cylinders with burned exhaust valves pass a comp test? At this point I have decided not to pursue fixing this car. Thinking someone might be interested in the Mega Squirt set-up; I have stripped it out of the car. There is much involved as a new engine harness was made to incorporate the 92MY FL1 connectors etc. It has the reluctor wheel welded to the front pulley and a homemade bracket for the trigger. More on this later. The car can now be sold or parted out. If I were younger, and wasn't already building the S-Type JagRod and my 62 Corvette, I'd likely tackle it...but alas that is not my situation. I have pushed it outside and we all now how fast they can deteriorate. (Had the PO NOT done so, it wouldn't have started rusting to begin with, and I'd be much more motivated to save it.) I prefer to sell it cheap rather than parting it all out. Before this potentially happens does anyone know of someone wanting a cheap project face-lift coupe? I have borrowed a head jacking plate that I can retain for a bit longer. It will be the key tool to be able disassemble the engine. Unless a potential buyer wants the Mega Squirt, it would need a new harness. Thus it is a better candidate for a SBC or LS lump swap; OR sadly a parts car. I will get it up on the "Market Place" in due time. Mean while, I'm still working on the 90 convertible.