News:

Putting FUN and FRIENDLINESS, FIRST into owning and learning about AMC small bodied cars, primarily Eagles, Spirits and Concords as well as vehicles built in AMC's Mexican subsidiary, VAM.

  The AMC Eaglepedia can now be accessed using the buttons found below  This is a comprehensive ever growing archive of information, tips, diagrams, manuals, etc. for the AMC Eagle and other small bodied AMC cars. 

Also a button is now available for our Face Book Group page.


Welcome to the AMC Eagles Den.  A new site under "old" management -- so welcome to your new home for everything related to AMC Eagles, Spirits and Concords along with opportunities to interact with other AMC'ers.  This site will soon be evolving to look different than it has and we will be incorporating new features we hope you will find useful, entertaining and expand your AMC horizons.  And, if you were you banned at another AMC Eagle Forum and cannot log in here?  Let us know and we will fix it for you. 

You can now promote your topics at your favorite social media site by clicking on the appropriate icon (top upper right of the page) while viewing the topic you wish to promote.


  • September 15, 2019, 12:31:55 PM

Login with username, password and session length

Author Topic: Project SX4 Evo - SX4 Junkyard to Pro Touring  (Read 1240 times)

0 Members and 2 Guests are viewing this topic.

Offline LeviBetz

  • Eagle
  • **
  • Posts: 33
  • Thumbs Up 1
Project SX4 Evo - SX4 Junkyard to Pro Touring
« on: July 30, 2018, 09:43:07 PM »
    Hey folks, new member here with a fresh project car. Back in high school (I'm younger so that was *only* 8ish years ago) I had an Eagle wagon and always had an affinity for the quirky AMCs and Eagles particularly. I live in Alaska so I'm biased towards AWD cars, but I hate 4wd style pickups
   So about this car. A few months ago a friend posted a photo on facebook of a pick n pull junkyard I had never heard of. Way off in the background was a complete Eagle SX4! I had always wanted one, but wasn't searching for one until there was a 'get it or it gets crushed' style ultimatum. So I drove out there and took a look. Initially I passed it up as it looked real rough. I tried to find a better one locally but all I found was a car that was also fairly rough but the owner wanted five grand for it. After some deliberation and rose colored glasses I decided that I would take the plunge on the junkyard car. I called up the yard, put a small $20 down payment on it and picked it up. Turns out I actually snagged it out from under someone who wanted it a bit too late (sorry not sorry).
   Here are some photos from the yard:







   Okay, so now for the plan. It's still evolving, but basically my concept is the historical fiction of "what if" AMC had decided they wanted to use the "evo" rule of Group B rally to build a dominating SX4 rally car. But in my version of this reality, AMC also decides they want to sell it as a nice performance street car to go after sports cars. So that's what's imforming my decision making process roughly. I don't really plan to make it hyper-period correct, but more to just give it that sort of experience.
   So for the modifications we'll start outside and move in. The body externally will remain largely stock, with some extra bits. I think I'll get a Spirit AMX spoiler for the front (which will require some tweaking to mate up to the flares), and I'll probably delete and clean up some trim to try to clean up the look. Of course anything I do I'll photoshop first, so I'll try not to paint myself into a corner.
   Staying on the look, but moving into the suspension, this will be the largest challenge. First off, I will make it lower. Probably around stock 2wd amc height or a bit lower. To accomplish this, I think the plan of action is to retrofit an alternate spindle which has less distance between the upper balljoint and hub. This will lower the car without touching the spring/shock geometry so I can maintain travel there. Of course to match the spindle change, I'll need to reloacte my lower control arm inner mount point and strut rod mount point. The lower control arm inner mount will by far be the biggest challenge. Moving the mount point will put it right in the way of the steering linkage, so that will need to be re-eingeered too. I can either try to move the whole gearbox/idler arm forward, or retrofit a rack and pinion. It seems like people have success with SN95/fox body mustang racks, and that's an easy mount to fabricate. I'm leaning towards the rack for feel and because the stock system has pretty bad bump steer geometry. Also I'll note that, from my measurments and simulations the stock Eagle suspension has about zero camber gain under bump/droop. So combining the new spindle and relocated mount point, I can change the camber curve and make it handle much better. Don't get me wrong, it totally makes sense why they would design it that way for a tall lifted vehicle, but bad for cornering. Zero camber gain means less grip as the suspension rolls more, so it helps keep the car stable and prevent rollover. Less of an issue once it's low. As for the rear, I'll start by just flipping from spring over to spring under which will drop it a bunch. I've got a rear suspension assembly laying around from a 2013 Subaru STI so I may section that down, retrofit a ford 8.8 center and retrofit IRS.
   Moving onto the drivetrain, this is the spicy part. The plan is big power... hopefully. I'm going to try a little sloppy mechanics style action and see what I can do with a 4.0l. I've already picked up a 'running' craigslist blue light special 4.0l for $150 so I plan to start by building a microsquirt harness and getting it running NA before eventually putting a cheap turbo on it. In the bottom end I plan to get some drop in pistons to mitigate the common piston skirt failure and balance/polish/arp bolt the connecting rods while I'm at it. The other fun piece of the engine plan is to chop the tiny plenum off a 4.0l log manifold and fabricate a sheet metal plenum to use a much bigger plenum volume and throttle body. The stock 60mm and small plenums seem to me to be a significant restriction, we'll see. And lastly I want to make the engine RPM, it's one of my criteria. So radical cam, and try to stabilize the valvetrain as much as possible. LS valves seem possible, I'd like to try to run LS rocker arms as well, but otoh V8 rockers tend to be setup different than I6 rockers, we'll see how it mocks up. I figure if I can use almost entirely LS valvetrain, it'll make the valvetrain pretty safe for RPM. Also LS stuff is cheap as chips. As for boosting the 4.0l and my evidence for this being possible, I'll point to Car Craft's article on Newcomer Racing's turbo 4.0l that did 660hp on a china turbo with stock rods (polished/arp).
http://www.hotrod.com/articles/horsepower-turbo-4-0-amc-jeep/?sm_id=organic_fb_HRN_trueanthem&utm_campaign=&utm_=5a9935bb04d30143165b4320&utm_medium=&utm_source= - https://www.hotrod.com/articles/horsepower-turbo-4-0-amc-jeep/?sm_id=organic_fb_HRN_trueanthem&utm_campaign=&utm_content=5a9935bb04d30143165b4320&utm_medium=&utm_source=
And this engine was built to redline low like a stock jeep which means that cylinder pressures at 712.6 lb/ft and 4600rpm were very high, which is even more strain on the bottom end than I plan. I plan on having the power peak higher up (6k+) which means less peak torque, less strain on the rods/pistons/crank. Of course the big concern with my plan is that AMC I6s (and most 7 bearing 6s) have a crankshaft and camshaft harmonic that has been reported to break cranks/cams. For a 150$ longblock, I'm willing to take that risk and send it. I've really only heard of actual failures with 4.2s and likely 4.6 strokers namely in the applications of the IMSA gremlins and circle track racing. It's worth noting that these engines spend a whole lot more time at that rpm to cause that failure than a street car with ocaisional autox/track use would. We'll see.
   Moving into the interior, I'm not totally solid on my interior plan. I will definitely replace the seats with sportier seats, but the challenge is that I'd like to find something that looks a bit 80s. It seems like what would be the period look there would be old recaros, but otoh $$$$. It seems like the look of 80's sports seats is to have a lower cusion that protrudes forward past the bolsters, while the backrest only has lower bolsters with shoulder bolsters not coming in later and separate headrests with those rad recaro style mesh headrests. I have some cheap NRG seats in my other project car ('73 Super Beetle) and they're *okay* but not totally sturdy. As for colors, etc, I want to do something spicy with some geometric style fabric inserts in the seats, maybe tie it into the door cards. So again, not totally sure what I'll do here.
   As for the trans, I plan to simply bolt in a Jeep AX15 which is actually made by Asin, who happens to use the same design in the Toyota R154 which is a common transmission in modified Toyotas with 2J power etc, so some upgraded parts are available and it seems to handle power well. For diffs, the rear will probably end up being a ford 8.8 at some point either with a live axle with 4 link or using an Explorer center section if I do the Subaru IRS. For the front, S10s and GMC syclones seem to have good luck with their front diffs, which use the same style CV axles as the Eagle (same inner and outer CV), but I may try to match ratios to the stock front Dana 30 and see how it does. I think most of the strain on the drivetrain will be in the rear anyway. Worst case, I'll have to fabricate some diff mounts which shouldn't be too hard.

  Okay, wow that was a rambletron. That's the plan so far. I shot some video of picking it up, and plan to cover some of the build in a youtube series, but I've planned lots of youtube videos I never actually produced hahaha. To finish up this intro post, here's a photo of it tucked away safe in the garage, miles from the car crusher.



*Crossposted to both AMC Eagle Den and The AMC Forum, hopefully that's okay*

Offline eaglefreek

  • Moderators
  • AMC Eagles Den Addicted
  • *****
  • Posts: 4009
  • Thumbs Up 209
Re: Project SX4 Evo - SX4 Junkyard to Pro Touring
« Reply #1 on: July 30, 2018, 10:22:53 PM »
Glad you made over to the forum. I'm Rick Pitz on the Facebook group. Before you get too crazy with the engine, I recall there being an issue trying make these engines rev. Something about harmonics and stuff coming apart.

Found some info, you might have seen it before, though. A few posts down a guy talks about harmonics at 6500 rpm.
https://www.naxja.org/forum/archive/index.php/t-18022.html
1986 AMC Eagle Wagon 4.2L/4.0L head, AW4,NP242, Chrysler 8.25" rear.
1981 AMC Eagle Wagon As Seen On TV  Lost In Transmission


 

"I know he'd be a poorer man, if he never saw an eagle fly,
Rocky mountain high"  John Denver
Click for Fayetteville,TN Forecast" border="0" height="100" width="150

Offline TEagle85

  • Eagle
  • **
  • Posts: 142
  • Thumbs Up 5
Re: Project SX4 Evo - SX4 Junkyard to Pro Touring
« Reply #2 on: July 30, 2018, 11:02:45 PM »
Looking forward to the build. Ive been eyeballing some kind of rack and pinion fabrication. Maybe Electric?  If you can get rid if the steering pump and steering gear it opens up a perfectly sized space close to the exaust manifold for a turbo.   

Offline LeviBetz

  • Eagle
  • **
  • Posts: 33
  • Thumbs Up 1
Re: Project SX4 Evo - SX4 Junkyard to Pro Touring
« Reply #3 on: July 31, 2018, 02:59:39 AM »
Re: crank harmonics. That is a concern, like I said these 4.0l cores are so cheap that I think it's worth the risk for science haha. Maybe I'll contact fluidampr and see if they could make a 4.0l harmonic damper. If you could get more harmonic damping out of the pulley, I'd imagine maybe you could mitigate those harmonics and prevent damage. Acoustically it makes sense, I'm a musician as well so I could see how a fluid crank damper could act to absorb resonant frequencies (kinda like sound deadening and mutes do).

As for turbo hot side and steering, I think what I plan to do is hack up the stock 4.0l header which is honestly quite good and flip the bends around so it aims forward, I'd really love to have the turbo on the passenger side to make intercooler plumbing better and get heat away from the intake manifold. It looks like I have room to run a downpipe down the front side and back up, but with a gearbox steering the middle link may move forward enough to limit that. Either way the hot side doesn't need to be huge, the cold side is more important for turbo spool and such. So ideally I'll have a rack, a small heat shield and a downpipe dropping under the front of the oil pan and back up on the other side. That way my downpipe can be nice and large and dump basically right into where the stock exhaust ran with a big single pipe out to the back.

Offline LeviBetz

  • Eagle
  • **
  • Posts: 33
  • Thumbs Up 1
Re: Project SX4 Evo - SX4 Junkyard to Pro Touring
« Reply #4 on: August 01, 2018, 06:02:12 AM »
Update time. I officially got the title today, so I'm more confident in firing the parts cannon at this thing.

   Today I decided to do some evening wrenching and test some stuff out. Namely I wanted to test moving the hub upwards to just check out the CV axle angle to make sure I'm not going to need to also raise the diff and go really crazy. I also just wanted to start getting stuff apart and freed up. I first tried removing the spring/shock, no luck there as the downtravel limits the spring, so I'll need to use a compressor to get it out. Then I realized I can actually just separate the upper BJ and raise the lower control arm/spindle up. So I did that, amazingly it came apart without too much fuss. Even the sway bar endlink came apart without breaking. I also removed the bumpstop to gain a little extra uptravel. Here are the results of the mockup!

Here's the wheel bolted onto the hub to check fit. This is probably actually lower than I want the car to sit, although maybe I'm misjudging that due to the 205/75/15 tire.


You can see it's really tucked up in there. I'll likely have to find some clearance to open up the wheel well. I may even remove or move the flares, I'm not sure on that.


Here's the distance from fender lip to hub. Keep in mind the flares on the eagle actually extend the fender lip downwards versus a standard AMC fender.


Wide view of the action. Note the top of the spindle tucked into the spring hahaha


Here's the infamous CV axle angle. You can also see that the diff does have a bit of room to move upwards if push comes to shove.


Here's an example of the CV axle angle on a lifted eagle. This is a 2" lift I believe? Seems somewhat similar to mine, just flipped down the other way. I figure if this is fine, then my angle is fine.



Closing thoughts, I thought today's experiments were very encouraging. Other thoughts on CV axle angle, if the spindle swap pushes out my cv axle length, that will also help as the rise will be equal but run will be increased. Also if I do end up swapping to a different front diff, a narrower diff will help this, so I could aim for that. I need to attack a junkyard with a tape measure sometime I think.

Offline mudkicker715

  • Administrator
  • AMC Eagles Den Addicted
  • ******
  • Posts: 2628
  • Thumbs Up 163
Re: Project SX4 Evo - SX4 Junkyard to Pro Touring
« Reply #5 on: August 01, 2018, 09:50:56 PM »
This might work if you got the big joints on there. I think the baby motor had shorter joints.



Manitowoc WI

Offline LeviBetz

  • Eagle
  • **
  • Posts: 33
  • Thumbs Up 1
Re: Project SX4 Evo - SX4 Junkyard to Pro Touring
« Reply #6 on: August 01, 2018, 10:59:49 PM »
They look pretty big to me! A friend suggested I check out the Porsche 930 CV that sandrail guys run. They tend to handle lots of angle well with a 6 ball setup more like an outer CV. I could see it being fairly reasonable to adapt onto the CV flange with it having just a different bolt pattern and an indexing ring thing. But that would be a billet part of some sort I'd have to have made.

Offline LeviBetz

  • Eagle
  • **
  • Posts: 33
  • Thumbs Up 1
Re: Project SX4 Evo - SX4 Junkyard to Pro Touring
« Reply #7 on: August 03, 2018, 07:47:50 AM »
A quick update today, just acquired some more parts. I scored a pair of s10 knuckles with brakes and everything for $30 off craigslist. I also ordered a microsquirt ecu, so once I can come up with a wiring harness to get pigtails from I can start wiring the 4.0l for it's swap. In the meantime I've still got lot's to do with my house so it'll be intermittent progress still.

Offline jebidia24

  • Eagle
  • **
  • Posts: 36
  • Thumbs Up 2
Re: Project SX4 Evo - SX4 Junkyard to Pro Touring
« Reply #8 on: December 05, 2018, 10:05:41 AM »
 I like your project.  I am undertaking a similar project with my SX4 (period-ish group B/A homologation special).  Mine came with the iron duke which died so I put in a 258 out of a wagon I had.  Luckily that meant I had all the correct parts.  I have replaced all my bushings with Prothane urethane bushings which I also recommend. I am also building a 79 Spirit into a rally car so I have lots of Spirit suspension parts that I can use.  I am lowering mine down to the stock Spirit ride height using the Spirit front coils and the rear spirit leaf springs and mounting points.  For your rear, Al at control freak told me that the Spirit 4 link setup that they make will fit the Eagle.  Not sure if that is out of your price range but your could look at it and get an idea of how to make a 4 link setup for your eagle.  If your going to put serious power through the drivetrain, the Ford rear end is a good choice and is the easiest way to get rear disc brakes.  Also, don't discount the idea of going to an AMC 20 with the proper track width.  They are easy to find, relatively strong (much stronger than the AMC 15 you and I have) and have plenty of performance parts available.  There are 258/242 Jeep companies out there that do high speed desert racing so the technology is there for a relatively powerful, fun inline 6 engine.  Just remember, the AWD/4WD system AMC built (no matter the trans, diff, or transfer case combo) will eat up your power to wheels much more than a newer AWD car with modern all-in-one transmission and transfer case (i.e Audi's Quattro system, Subaru's AWD, or Toyota's Alltrak).  For increasing the RPM range, 505 performance makes a roller cam kit that goes into 258/242 inline six engines that will raise the red line up to 6000 RPM.  With that aggressive of a cam though, the car will probably idle poorly.  They make less aggressive roller cam kits also with better everyday drivability at the expensive of some lost top end.  505 performance also makes a turbo kit for the 258/242 but I am not sure of the price.  Roller rockers are also a good choice to increase RPM range capabilities but you may want to stick to AMC/Jeep parts as they are tried and true and guaranteed to fit.  I'm sure you've already looked at this but take a good look at your car's rocker panels.  They tend to rust out and can be a pain to find replacements.  Either way, good luck and I look forward to hearing more about this build.

 

SMF spam blocked by CleanTalk