I was offered a Jaguar V12 Free on one condition, I have to make it fit in a Fiero.
Has anyone ever tried this swap? Ive been surfing alldata's wiring diagrams, doesnt seem impossible the wiring is actualy pretty simple, very few sensors. Theres like 3 ECMs though is the only issue there. The engine is approx 25" wide from manifold to manifold, 16.5 inches from crank center to top most piece, and 33.5" from bellhousing to outermost crank pulley. Its not entirely out of the size possiblity though I think the frame would need a heavy massaging and definitly would require moving the tranny over.

Does anyone know who might be able to make an adapter plate for a Fiero bellhousing, or andone know of a tranny that would sit lower and allow for more movement to the left??

DON'T DO IT! This is a very expensive motor to repair and not worth the trouble. You see people converting their Jags to V8 Chevy's all the time and I once considered buying a Jag to do the same thing until I talked to some friends of mine that repair Mercedes for a living who know about this engine all too well.

Is it a very expensive motor to repair, or to have repaired? Why is it so bad? I havent really priced parts but just curious

Ducattiman????

D & R Motor cars fit a BMW V12 in one of their Diablo kits so either a stretched and widened Fiero frame was used or a completely custom frame was made. Any engine can be made to fit almost any car, but it may come down to your budget and how much work you wish to do. Without widening the Fiero chassis, you can bet that a V12 won't fit.

[This message has been edited by Dennis LaGrua (edited 05-21-2005).]

You have to ask yourself....why is he giving away a v12, and what is wrong with it?

Consumer Guide® Estimated Repair Costs for 1990-94 Jaguar XJ6/XJ12

This table lists costs of likely repairs for comparison with other vehicles. The dollar amount includes the cost of the part(s) and labor (based on $50 per hour) for the typical repair without extras or add-ons. Like the pricing information, replacement costs can vary widely depending on region. Expect charges at a new-car dealership to be slightly higher.

Item Name Repair Cost
A/C Compressor $920
Alternator $220
Automatic Transmission or Transaxle $1,010
Brakes $230
Exhaust System $1,035
Radiator $800
Shocks and/or Struts $900
Timing Chain or Belt $705
Universal Joints $215

I found this on a Jag forum...

When one bank quits working because of a distributor failure like that, that bank is still getting fuel, which gets sent unburned into the exhaust, and can actually catch fire and burn your car up when it hits the cat. Engine fires on Jags for this reason are not that unusual. The thing is, the V-12 is such a silky smooth powerplant, even when half-dead, that other than a bad loss of power, there are usually no other symptoms, and least not until you see smoke and flames.

Check out this conversion site, I thought it had some interesting information...

http://www.johnscars.com/xj/xjv8.htm

I have a Jag V-12 sitting in the barn, and I have looked at every way of fitting it in (longituginal and transverse).
There is just no way to fit it in unless you stretch the frame. It is just to long a motor.

Gene

------------------
87 Notchie 4.9 with Delta Cam, Shaved Heads and lots of tedious porting
87 SE 3.4TDC swap almost done (when it gets warmer out)
87 Notchie Caddy 472 longitudinal coming soon

quote Originally posted by scrabblegod: I have a Jag V-12 sitting in the barn, and I have looked at every way of fitting it in (longituginal and transverse). There is just no way to fit it in unless you stretch the frame. It is just to long a motor. Gene

Just put the 5-100mm bolt pattern on both ends of the crank and roll on!

------------------
RickN
White 88GT 5spd
White 85GT Auto

http://www.jagsthatrun.com

well, all the comments are, apparently kinda negative and I have to go along with that. I had an XJ12L and had high hopes for it. Keep in mind it is not a big displacement motor; I think about 326 ci IIRC.... Finally let it go; couldn't keep it running and wildly expensive parts. And a high rate of consuming parts, too. You know you're in trouble when you go to the local Jag dealer, parts department, and the guy comes up to the counter (called the "stockroom", by the way ) wearing a suit jacket and tie............ uh oh.

Even since then I have thought about them; I LOVE the idea of a V12 growl/purr. And I looked into it briefly for my current project; a 308 rebody (which would NOT be an ideal v12 swap- it should be longitudinal) but my impressions were that there are a LOT of variations of heads, blocks and all the parts that go into each. It would be a project by itself to figure out what engine/heads etc you would and probably 'would NOT' want.......
that was my finding, unfortunately.
So now it is off my radar screen. If I ever think of something like that again it might be the Beemer V12; sorry for the bad feedback but that was my experience.
good luck with whatever you decide.
g

Ducattiman is working (..move yer ass Duc ) on a longitudal mounted BMW V12. here

yeah yeah..i am moving,,goning as fast as i can..but i cant help it if other projects pop up..

If you can do 4 x 12"s you can do 1 x V12 too....

lmao

Theres no doubt that I would be doing any and all repair work on it. By the standards at my shop, most of those prices are lower than most domestic cars. Theres no doubt parts would be more expensive, but looking at the electrical system, theres very few sensors. Also I wsas thinking of retrofitting a GM alternator and AC compressor (if theres room) onto it. I measures from the outside of the frame rails theres ~46" between them. Guestamates put the width of the engine and tranny at 11 and 33.5 or 44.5. And thats using the engine as is. If I can knock down some of the pulleys it gains me more room. The only major problem I see is clearing the strut towers. Ive got to do more measuring for that.
I dont see any need for cats, so If I do loose a bank I just need to worry about putting out the fire on the guys car behind me

And hes giving me the engine cause hes a good friend of mine, and I think he thinks itll be funny to see me try to cram it in there. And plus when I do he'll be selling me a new rera bumper

More measurements are in order here. Does anyone know what the smallest tranny would be?

11"? you gonna be using an automatic?

The automatics are thinner in the required dimension than the manual transmissions...

The Jag V12, despite being aluminum, is a HEAVY engine. My dad used to have a small business putting Chevy engines into Jaguars. The front end of a XJ-12 would rise noticeably after the conversion. Of course by the time he saw them, the springs had usually sagged some, so this was OK...

The engine iteself is pretty reliable AS LONG AS IT IS NEVER OVERHEATED.

It has a very short stroke, so if you have deep pockets it can gain a LOT of displacement with a custom crank.
My dad knows a guy who had a bunch of lawyer clients back in the day who were tired of having their XJS's embarassed at stoplights. He had billet cranks cut to stroke the engine from 5.3 to 7 or so litres. The cranks and custom pistons were set up to use 6" Chevy rods, which were made of Titanium for these particular engines.
The short block mods were of course accompanied by appropriate breathing and cam changes... the resulting engines almost made more power off idle than the stock engine did at peak output.

Size is more of an issue than choice here, theres no room for the shiftercables cause the tranny is going to be shifted as far to the left as possible, putting any shifter brackets into the frame rails. Im not really looking to soup it up, 313 HP and 350 lbs of torque should be more than enough.

Long but informative...

Just some Updated info about the Jag Costs.. (for accuracy). I know most on the board are of a technical nature so incase anyone is interested in a V-12 Jag, I'd like to add my input.:

I currently have a 91 XJS V-12. I've owned 3 XJS V-12's. Would I attempt to put the V-12 into a Fiero or Kit Car, No.

Although some of the older V-12's do have some problems (Mainly cooling), the V-12's below the 1989 era do not have the Marelli Ignition that is prone to failure and the engine fires that are mentioned. Pre 89's have the CEI Ignition from Lucas (Which has some of it's own Issues but is generally reliable).

.

The fix for the "Dreaded Engine Fires" that everyone assumes are so devastating is about $1.00. That's correct. $1.00. Most of the engine fires come from the use of non-oem distributor caps. 1st fix, - Use a OEM Marelli Cap. Like anything else, you get what you pay for. Does anyone here use oil from the dollar store for their car??

The 2nd fix (Yes, old or un-replaced Marelli caps are still prone to this failure). (you simply can't put off service and a tune up for 80,000 miles on a V-12 just because it "feels fine" while driving. Many owners did. The caps (even cheap aftermarkets) can be modified with a aluminum insert and dab of silicone to prevent an arching and take care of those "pesky" engine fires... Ha Ha.. They are not as common as you think...

Also. No matter what you read, only a true "idiot" can not feel that the Jag is only running on 6 cylinders. Pull 2 spark plugs off and yes, many who have never driven one may not even notice but if you drive one every day, 1 burnt wire, 1 miss and your certainly feel it.

The main problem w/ reliability on these cars is Lack of service by "Qualified Techs". It always has been. The motors themselves were designed to run Lemans and running for extended periods of time (like 24+ hours) at high RPM's are no problem for the V-12. Jaguar did have many issues especially in correcting known problems and this really led to the bad press they got (and It was much deserved). While other manufactures promptly (kind of...) took care of their production issues and problems, Jaguar let lots of problems go un-corrected for decades!. Even the simplist of fixes were allowed to go years without resolution by Jaguar.

While many cars have had problems, the majority of the V-12 Jag's problems are related to poor service by unqualified people - Even at the Jag dealers..

As far as High Costs to repair, :

AC Compressor is a GM A-6 on most V-12's. Cores can be found in any junkyard and replacement Compressors are no more expensive than for a Chevy that uses the A-6 (Older Mid 70's cars.) You can also upgrade to the new compressors. Yes you may have to fabricate brackets but don't we do that here anyway.....??

Jag's V-12 Auto Trans is a GM Turbo 400. (There is no Trans Axle). The case is modified to fit the Jag Block but anyone who can work on a GM trans can rebuild you Jag Trans. Shift kits and parts for the Turbo 400 are used in the Jag. This is a great way for transmission places to rob owners of Jaguars. $1000 stated in a previous post is excessive. If they are paying $1000 for a Jag Transmission Rebuild, they are getting robbed.

Brake pads are available at most Auto Parts Stores. I prefer NAPA. Again, you get what you pay for. Putting Pep Boys $23.00 pads on a $48,000 car and you can imagine your results. (yes, Jags were expensive. Talk about depreciation due to reputation!!)... Premium Pads are $45 a set fro Front and appx $60 a set for rear. The rear pads "pop out" like little cassette tapes and are not that difficult to replace. (The jags rotors and brakes are Inboard on most XJs cars so the brakes and rotors are about 6 inches away from the rear end housing and you have to be under the car to change pads.

Timing Chain - Good luck finding a Jag that may ever need one! - While they do go bad, it is not common. A Jag Timing chain and tensioner will often look brand new and exhibit no stretch at 200,000 + miles. A chain replacement is also not that difficult. Much like many BMW's, Your remove the upper cam cover, find the removable link. Attach the new chain to the old chain via the link and then slowly rotate it around. Clip the new master link and you are finished. A job certainly anyone on this board can do.(Yes,,, having it done can be expensive).

Alternator - $260 I think was mentioned. A GM alternator $45 can be retrofitted for use in the Jag with no problem by almost anyone that is handy with cars.. The original Lucas Alternators have gone in excess of 150K in most cases. In that time, many domestic cars have had 2 or 3 alternators so even though an OEM unit is higher priced, you often only do it 1 time depending on how long you own the car.

Pre 1989 CEI Ignitions use a GM HEI Module (1974 vintage seems to work best as far as replacement). Crooked mechanics have been charging Jag owners $1500 - $2000 for this "very difficult" Ignition "repair" for years. $25.00 for a new module if yours goes bad. (and they do because of the poor location on the intake of the V-12. Moving the Ignition Amplifier to a cooler spot during a replcaement is an easy job and well worth it..

Custom Ignition Wires for the V-12 for $200 - $300+ Dollars during a tune-up froma "reputable mechanic". Accel custom wires 8mm (original Jag wires are 7mm) do the job great. $30. Make your custom length and use some heat sleeve on the inner ones where they do get hot from the intake.

AIr pump is the same as a GM unit on most cars. Why are people charging Jag owners Hundreds of Dollars when a $30- $60 GM air pump is the same one with the same part number!

I can't tell you how may Jags I've seen that the owners have stated "really suck" and overheat, only to find out that they removed both thermostats!. Unlike many other cars, you can not remove the thermostats from the V-12. Temps will be excessive. Yes, the OEM thermostats are about $17 - $22 each but for saving the $40 many owners and mechanics are willing to risk destroying the engines by using cheap replacements or no thermostats at all.

Radiators are expensive - $600 and no matter how much "Flack" I get on the Jag board from Jaguar "Purists", The Original 1 and one half pass radiator is and was a poor design. Jag knew it then. And we all know it now. Although I have the original rad in mine, I'd never replace it with another OEM unit. BE-Cool make a replacement for $500 I believe that is a single pass. You can also use a custom radiator and modify the "multiple" coolant hoses that come from the Jag. For a Few Hundred $$$ you can modify the system and then be done with it. God knows I'll be doing mine if it starts running hot.

Don't get me wrong. Their reliability is'nt stellar but the V-12 powerplant itself is a good strong motor and capable of exceeding 300K miles (and often does). My last one had 200,000 virtually trouble free miles. The one before it had 240k and my current one literally is'nt even broken in at 89k. There are many other owners like me.

The jag owners manuals actually suggested putting 2 bottles of Barrs Leaks into the coolant at each change! This led to many cooling issues, excessive temps, plugged up radiators and really helped to make the Jag un-reliable. Any V-12 Jag that anyone has now (whether they realize it or not) needs a new radiator. Period. If it's been serviced by Jag, I guarantee it's 1/3rd plugged up.

My 91XJS runs like a dream, has plenty of power and has been driven from Texas to PA without a problem. Well taken care of (like any car) they are nice cars.

Would I put the engine into a kit. No way. Not fast enough from a dead stop. Never designed to be that way with the stock 2.88 rear or the optional 3.14 like mine has. Performance parts are $$$$$$$. but... As far as top end..... My 91 Euro will Exceed 170+ mph from the factory and cruising in the V12 is one of the best feelings ever. That low rumble is great and talk about pulling........ From 60mph to 120 is in a matter of seconds. What a rush.

Anyone on this board who works on their own cars can "Handle a Jag" . Knowledge and Maintainence are the key. If you don't work on your own cars - stay away unless your wallet is nice and fat.

If anyone is considering one, search the net for Kirby Palms Jaguar Book -" Experience in a book". Its a Free Huge archive in book form that you can download in Word format. This book is a must for all Jag owners or anyone considering one.

Hope that gives eveyone a bit clearer view of working on one of these beasts. I think I'll go take mine for a cruise now..

[This message has been edited by 3084me (edited 05-23-2005).]

The shop next door to mine is mainly Jaguar/MG/Fiat repair (and older ones at that!) Yes, we have enough of them here in the area that the guy does a very good business.

As mentioned above, the engines themselves are not usually the problem areas. The Lucas wiring is prone to problems but thats not the engines fault. I think most of the problems he encounters that end up being nightmares are caused by lack of proper maintenence. Years of that all add up to a car with many problems. 3084me hit it on the head - lots of problems from non-OEM parts being used over the years too.

I honestly can't remember the last time he had a Jag in with an actual engine problem (internal). Usually it's bad fuel tanks, wiring, that kind of thing.

I recall hearing that they *may* have had a problem with crankshafts? But, that is only what I *think* I heard, and if they did like a lot of cars it was probably only for a year or two but it gave the entire model run a bad name (don't you hate that when a car gets a rep from something like that )

That being said the jag engine is not a bad unit. Like most high end luxury cars that get up there with age the car might not have been maintained/taken care of properly, and that is why his friend may be offering it to him for free.

It would be an interesting swap, and a first I'm sure, but I don't think the engine matches the parsonality of the car. But hey, do what you want, it's YOUR car!

Lut us know what you decide,

Brian

3084, big old plus to you for all that info. What people dont realize is that whoever makes an engine, they all work the same. Ive been measuring more and am starting to get a little worried. There might not be enough room between the struts period. My initial measurements were promising, but it also just dawned on me my new meaurements were on my 88. hmm. anyway, Im not too worried about it being slow off the line, its gotta be faster than my 3.4DOHC, being 110 HP and 150 ftlbs stronger, and whos going to be gutsy enough to race me with a V 12 ?!!
Plus I dont care so much about the speed as I do just having a V12 Fiero lol. Ive got to get back out to the J/y for better engine meaurements.

I think a BMW V-12 would be a much better engine choice. It's even kind of small as far as exterior dimensions go. Then you can add some turbos.......