Swap jag v12 into AMC EAGLE

somedai1somedai1 Member Posts: 416
Yeah - probably crazy - but can anyone offer any help on this swap - can it be done - want to keep the 4wd function and put a v12 in a '88 amc eagle - had a Jaguar XJS HE V12 and loved it - so anyone???
the other option i wanted to explore was a 4cyl turbo like from eagle talon or twin turbo 6cyl like from 300zx


  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    The Eagle is such a foul-handling, clunky car that I think putting a lot of power into it before re-working the chassis *considerably* will result in a very disappointing vehicle. The Eagle is really a truck and should be approached more like one would build say an off-road competition vehicle for the Baja or something. Putting a huge powerplant in the front end would be disastrous I think, to say nothing of the spotty reliability of a Jaguar V12.

    A hot small turbo motor would work a lot better, IMO, preferably Japanese with no Chrysler overtones. Also the Eagle had a pretty anemic motor, so I don't know how much power the stock drivetrain can stand.

    I'd build it simple and rugged, to suit the vehicle you have selected. Mating sophistication with the primitive is more like a street rod, which is "show", not "go". That's why I was suggesting a good chassis overhaul before you even think about motors, unless of course this vehicle is to be trailered around.

    If it's all for show, you can do whatever you want, because the eyeball value is the goal, right?

    Visiting Host and his two cents :P
  • somedai1somedai1 Member Posts: 416
    thants for the 2 cents - i mostly get no response on this - so thanks - the fastest i ever drove this eagle is about 100mph - handled pretty good considering... but i don't think the v12 either from a jag or bmw would be much heavier than the cast iron inline 6 i have since thery're aluminum - v8's have been done - so i'll probably end up going that route ultimately - cause no one is willing to entertain the thought of a v12 - as far as japanese turbo - do you know of any that might work - i'm not familiar with those and it would most likely have to come from one with rear wheel drive - got any suggestions?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Well the Eagle handles like a truck---it's stiff and I guess as long as you are on a smooth road and don't do anything SUDDEN, you'd be okay. But start turning fast on bumpy surfaces, and I think you'd pogo-stick right into a tree. This is a primitive car remember.

    A V8 is certainly the cheapest and easiest way to go here---crate engines are SO CHEAP for the power you get. I really don't see any advantage of a Jaguar V12---they are gas hogs, they catch fire with alarming regularity, and they are expensive and difficult to work on.

    Really a V12 is built for smoothness, not power. Making an AMC Eagle "silky smooth" seems like a contradiction.

    Japanese turbos? If you dare, a Mazda TT from an RX-7 would be pretty hot, and that's a RWD car. It's a bit of a delicate engine however, prone to detonation. So you have to be religiouos about premium fuel, frequent oil changes and very efficient engine cooling. But that engine will pull like you wouldn't believe once you get the revs up. Not a torque motor though, not at all. Maybe a Nissan 300ZX? it would probaby fit.
  • somedai1somedai1 Member Posts: 416
    yeah - the 300zx twin turbo was a thought - mind you - my whole approach with this car is to modernize it so it won't be such a clumsy ride. i remember the smoothness of the jag - i never smoked the tires with that car - but smooth power is good enough - and losing torque is not something i would want... i'll keep researching to see what the best way to go will be for me - the biggest deal is that i want it to be different if not radical - almost every hot rod has a 350 chevy...

    i know i'll have to upgrade some stuff with additional power - i didn't think about the chassis though - i was using KYB shocks all around, poly bushings on the rear springs (the entire front end will have poly when i'm done) and the wheels in the rear are 10" wide so the cornering was much improved - will do rear disc brakes conversion too - so i'm gonna get it up to speed for this modern era eventually - the power plant is the only thing that I am unsure on...
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Actually Hemmings Muscle Machines magazine this month has an article about building a 4.0 AMC stroker motor.
  • somedai1somedai1 Member Posts: 416
    any idea what horsepower the stroker motor produces - i saw something like 190hp - nice but i'd like more - if worked right the same 4.2 motor can produce 235hp but costs around $4k - changing to a 4.0 head with various other mods gives about 210hp (6=8 clifford performance) lots of $$$ too - i expect to spend - but the cost to benefit ratio has to be good/acceptable
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    I think he was predicting 250HP. You really never know until you get on a dyno and then dyno-tune. Two identical motors can produce different results sometimes.

    The nice thing about a V8 crate motor is that you don't have to worry about computers and wiring harnesses---you can use a carburetor; otherwise you have to rip everything out of the donor car along with the engine, or alternatively, buy an aftermarket F.I. control system. That can get very tricky.
  • somedai1somedai1 Member Posts: 416
    you have many good points - it would also suck to get stuff out of a donor to find that it's crappy - so new crate stuff if more attractive to me but more expensive...
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    I guess you could get a throttle body injector motor out of a used GM car from the 1980s---that doesn't have much electronic control. Maybe a C4 Vette motor. They seem to be easily available.
  • dta1818dta1818 Member Posts: 1
    i have a 92 talon and i am wanting to take out my stock air filter and put a k and n filter in it. but i have a air sensor on it. i have taken it off to see what it would do and it would not give any boost what so ever.. so if you can tell me what i can do to fix this problem,. i have already put the sensor back on.. i just want to get rid of the air sensor some how. if u could email anything to me..

    email.. [email protected]

    thank you
  • paisanpaisan Member Posts: 21,181
    You can't remove the sensor. You would need to get a K&N Intake that is compatible with the air sensor you have on your car.

    Subaru Guru and Track Instructor
  • somedai1somedai1 Member Posts: 416
    i'm now considering getting a worked 4.2 I-6 that will put out about 275hp and a Powerjection I fuel injection system that mimics the look of a carb but is fuel injection... expensive but looks like the best way to go without having to do too many mods...
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    That's a very LONG motor. Think it will fit without intrusion into the firewall and lots of fabrication?

    I think a Buick turbo V-6 would be a fabulous way to go with this.
  • somedai1somedai1 Member Posts: 416
    the 258 4.2 I-6 is the stock motor.... a modified one could put out 275hp - but which buick turbo 6 could work?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Well it's going to be tricky with 4WD. I have no idea how one would engineer such a swap. I'm just dreamin'. :P
  • KirksjohnsonKirksjohnson Member Posts: 11
    Great Idea!!!! I would stick to the jag v12 but beware of the BL jags once ford bought them out the engine became alot better I would go with a 90 or newer they are great mills. As long as you have a donor car for the modules and what not and as far as the 4x4 working just use a divorce box transfer from a 70's ford high boy. Drive shafts will have to be made as well as linkages but that is to be expected. I also like the BMW v12 from the 750 IL Good power. Sounds like a driveshaft twisting good time. The v12 will fit perfect in there being they came with I6's anyway.
  • somedai1somedai1 Member Posts: 416
    NICE! that was a feel good post! no one really thinks it's a good idea... i figure it's the type of swap that would need a blank check and a lot of time and a really good shop that likes a challenge...
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    My main issue with the concept is that the Eagle chassis is kind of lame. Basically you are putting a beautiful engine into a 1950s truck chassis.
  • 3808catpickup3808catpickup Member Posts: 3
    this is a cool idea these cars are not that primitive the steering systems are the same that was used on the amxs and if i remember rite they wone a lot of nascar road course races not sure about the length of the v12 but wait isnt a 6 cyclinder half of a v12 ? the v8 would be the better idea but hay whatever floats your boat any way the transfer case not sure it would hold up to the input tourque of the v12 that and adapting the engine would be hard what you could use would be a t case from a olds bravada they are the same used in the cyclones they are a viscouse style tcase the part nm is bw4472c these were mated to a 4l60 tranny you can get build up and shift kits for these as well as a stand alone computer for the trannys brain at summit i was told that the older jag v12 had a chevy bell patern not sure on that so dont quote me the diferentials would hold up they are dana 30 although not the best for off roading they would be good for hauling [non-permissible content removed] on asphault google v8 eagle wagon there is a gut that did a v8 swap on an eagle check it maybe it would give you some ideas on design and fit up one thing if your going to race this car i would definately lower it they sit high throw some good anti sway bars on it stiffen up the springs you could have your self a cool cayon carver but do yourself a favor dich the bumpers there ugly as sin they look a lot nicer with out them i had an eagle but i built the six up offenhouser intake comp came split header and a holly 450 4 barrel carb i used to street race it for fun till i wrecked it i didnt win every race but they sure were cought off guard when it didnt spin a tire and blasted past them :)
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    The Eagle chassis is based on the Concord, first produced in 1978, and the Concord is based on the Hornet, which goes back to 1970. So yeah, it's a pretty old chassis setup and it never really handled any serious amount of power.

    I think you'd have to seriously strengthen this chassis or you'll twist it for sure.
  • 3808catpickup3808catpickup Member Posts: 3
    not sure about that allot of peaple use them for drag racing at least there two wheel drive cousins the amc spirit but as far as stiffening the chases a set of frame connectors would solve that :P
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    I'm sure they do that, yes, weld them right in there.
  • 3808catpickup3808catpickup Member Posts: 3
    sorry to afend you but if your going thrue all the trouble to put a v12 in whats a 100.00 pair of frame connectors :(
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    It's like the $1.50 ring on your parachute pull. No big deal unless you forget it. :P
  • grahampaigegrahampaige Member Posts: 51
    I have only one question


    If you want to go jag, do go the 12 lots of complexity and things to go wrong (that do expensively) If you insit on going jag you would be better with the AJ6 or the V8 of the same era. If you are going Jag 12 because you can get one cheap. There is a reason you are getting it cheap. (Run away. FAST)
  • captcarlcaptcarl Member Posts: 1
    As an Eagle owner of many years, I can tell you a few things about modifying them. Many here seem to feel that these cars are poor handling pices of junk. In reality, when the Eagle was introduced as an '80 model with full-time 4WD, they were considered to be excellent handling cars for their time. They could outhandle most American built cars of the era. If you lower the car on the suspension, put sticky tires on it, and add some subframe connectors, it will surprise many other more expensive cars when the road gets twisty. The problem is getting more power into them. When the V-8 swaps are done, the person doing the swap is generally looking for more power to go off-roading with. And in the interest of increasing the trail worthiness of the rig, they will also convert it to a straight axle in the front. The Eagle was the first 4WD with an independent front suspension (IFS) IFS does not lend itself to lifting the suspension, nor is it as durable in extreme off road situations. The IFS is very smooth on the road, as well as good handling. A straight axle swap will do away with the Eagles good road manners. The front axle on the Eagle was mounted directly to the engine block. If you want to keep the IFS, you will need to fabricate a front axle mount for it, which won't be easy, but can be done. I am assuming you would do the Jag motor for speed rather than trail running, and thus would want to keep the IFS. Your best bet would be to build the Six popper up. They are bulletproof motors that can take an enormous amount of abuse. The bottom ends are especially stout, having 7 main bearings to support the crankshaft, rather than the 4 or 5 main bearings that most inline sixes sport. As a show of what can be done with this engine, in 1978 (?) AMC built an AMX show car, and turbocharged a 4.2 and got 450 hp out of it. The stroker motor can be a very good way to go. Take the stock 4.2 liter crank & rods, and put it into a 4.0 liter block, and you have a 4.6 stroker. A little more mixing of parts, and you can get it up to 4.8 liters. Add a turbo, injection, and some headwork, and 275 hp is not unrealistic. However, the torque will be monstrous. It will make more torque than a small block V-8 will, and at a much lower RPM as well. You will scare the Hell out of a lot of other cars on the road if you go this route. You will need to beef up the driveline though, as they were engineered to handle the 110-130 hp that the Eagle originally put out. A note about stroker motors though: Due to the extremely long stroke, they don't like to be revved all that high on any kind of regular basis. Building a 4.2 won't be as cheap as say, a small block V8, but you will spend a LOT more money getting the V8 into the Eagle and having it be safe. I love my Eagle wagon, an '86. It is my daily driver with over 200K on the clock, and still purrs like a kitten. Last weekend, I took the old Bird on a 1500 mile road trip. It was perfectly comfortable cruising at 70, returned a bit over 18 mpg, and used only 1 quart of oil. The engine has never been opened. They are great cars, don't let anyone tell you differently. Over the years, I have run into many AMC "experts" who have told me what awful cars they are, while never actually having owned one. Like any other car out there, it depends on how they were treated by previous owners. Remember though, the newest Eagle out there is now 21 years old.

    A website you really need to check out if you want to do this is:


    They have info for everything you could ever need to know. There are members there who have built stroker motors, as well as V8 conversions. You will learn a lot through this site. Check it out. Good luck, and keep us posted...

  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Thanks Capt Carl---interesting stuff.

    I think the point was that your mods are what was necessary in the first place. In its stock form, it was underwhelming. But the early 80s were not America's high point for auto manufacture. Look at the poor '80-81 Corvette.
  • somedai1somedai1 Member Posts: 416
    Thanks for the vote of onfidence in our cars! I actually started drifting to the thought you mention... keep the stock engine and keep it simple. strengthen drivetrain to handle the new power of the worked motor and stiffen chassis - upgrade brakes and suspension and good to go! By the way - I am AMCDREAMS on the eaglenest site. I have the Eagle parked now for about 2-3yrs waiting to resurrect it - so all that time i'm putting thought into how to do it right - I get some over the top ideas but i find they are not really too outlandish and can actually be done. Somebody got an automatic transmission Lamborghini.. it all just takes money!
  • somedai1somedai1 Member Posts: 416
    Funny - I ended up selling the AMC Eagle - then ended up getting an '82 v12 Jag xjs - then sold that too! Ships passing in the night- never meant to be! Now all I have is an '07 Hyundai Santa Fe AWD - hmmm - what will I get to do with this? I still have a nitrous bottle I never used... hmmm LOL!
  • steverstever Guest Posts: 52,454
    For a while there the fad was to put nitrous in your minivan, so what the hey - go for it. :D
  • somedai1somedai1 Member Posts: 416
    I would really want something more permanent like turbo or supercharger if I could seriously get it done...
  • somedai1somedai1 Member Posts: 416
    nuttin but love for ya! Love it - even tho' I wouldn't have lifted it - and would have to keep it 4wd - but still - very cool!
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