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Front end similarities hornet/concorde/eagle?

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Malatrix View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Malatrix Quote  Post ReplyReply Direct Link To This Post Topic: Front end similarities hornet/concorde/eagle?
    Posted: Jun/12/2019 at 10:30am
I've got a '72 Gremlin and I want to know if it's possible to swap in the front drivetrain of an Eagle. I think having a Gremlin is cool, but being able to say it's AWD and have better traction in the wet is cooler. especially around where I live, the asphalt substrate is awful so everyone in a 2wd car spins tires everywhere when it rains.

I've read that the Eagle is the 4wd version of the Concord, which was essentially a facelifted Hornet. I've even seen Eagle Kammbacks which look more or less like the last gremlins. Is the axle/subframe from an eagle able to bolt in or at least line up to the early gremlin/hornet body/frame?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2019 at 11:30am
No. The floor pan is TOTALLY different, the seat mounting especially on the SX4 is very different, the front cross member is VERY different. Your floor would be among the biggest obstacles. 
 
There is not room for the Eagle stuff under other AMCs. The transfer case won't fit. 
What you read is a grossly over-simplified version. And no the Concord isn't just a face-lifted hornet - there were other changes. 
The Eagle also requires a larger wheel opening in the fender - AMC had to stretch the wheel opening forward about an inch or so to compensate for the wide wheel swing-out on turns. The first year they left Concord fenders on Eagle - and ended up with thousands of rolled fender lips as the tires would swing out and fold the front fender lip inward behind the trim. So the fenders are different because the wheels make a wide swing to compensate for the CV joint near the outer end of the axle. 
Different cross members, different lower control arms, different steering knuckles, engine sits a tad right of center, different floor pan, if it's a stick you have to use hydraulic clutch as there is zero room for clutch linkage so you have a clutch master cylinder and a clutch slave cylinder. Eagles are heavy so you need better springs. I think the SX4 is about 3200 or 3300 pounds with the sedan and wagon even more. And that's with a SIX. 
You would need an entire donor Eagle - and you'd need to either use the Eagle floor or do a lot of fabricating to make things fit. One comparison is that look at the console and rally gauges for Spirit vs. Eagle - Spirit has two rows of two gauges - not enough room in Eagle due to the very high floor hump so they had to do one row with all four gauges in Eagle. 
The front differential hangs from the engine mount brackets in Eagle - there isn't a "frame" to transfer. There are three brackets - the third that bolts to the Eagle block on the left side near the back supports the pinion to keep it level, the differential is otherwise held up to the engine by the engine mount brackets that bolt to the block - so you have to have an Eagle block to get the provisions to bold the pinion support up - or fabricate something really stout. 


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Malatrix Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2019 at 11:59am
Okay, I guess if it were remotely easy, there would be plenty of people already doing it. Thanks for the info!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote MacGyver Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2019 at 8:34pm
I can't speak for a Gremlin, but I did do that conversion on a Spirit!!
 
The single biggest modification was the transmission tunnel!!
But almost everything else was a simple bolt-in!!
 
I did have a donor Eagle...  Cut out the transmission tunnel portion of the floor, and
welded it into the Spirit!!
Reinforced the unibody structure with some subframe connectors to stiffen things up a bit, because Eagle's do have a few different strengthening "ribs" in the floor that the Spirit didn't have....
 
Swapped the complete front crossmember out of the Eagle into the Spirit and it bolted right in!! 
Everything below the upper control arms is Eagle...  Everything above is Spirit....
 
I used the original Spirit coil springs and it worked just fine!  In fact, I had to add a couple of leafs to the rear springs to raise the rear to match the front!!
 
I had no problem with the seats...  Quick and easy mod and they fit perfect!!
 
I would love to do this to a Gremlin!!!
But I'm guessing that since AMC hadn't yet thought about putting 4wd under their small car platform back in '72, many of the handy already threaded holes I used to bolt Eagle stuff up to the Spirit might not exist on a Gremlin! 
 
You Drive A What?!?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2019 at 8:48pm
So how did you handle the fender differences? Smaller tires? Because the front tires WILL rub on Concord fenders. That's why AMC changed them in 81.
Of course the rear differential is a matter of moving it UNDER the leaf springs like Eagle instead of over the springs like all others.

I assume you had an automatic otherwise you'd have to change the clutch pedal because Eagle was different - for the hydraulic clutch.

You obviously used the Eagle engine in order to have a pan clear the cross member (Eagle PAN is very different and the oil pump pickup screen is very different - longer) and to have the provision to bolt on the pinion brace.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote MacGyver Quote  Post ReplyReply Direct Link To This Post Posted: Jun/12/2019 at 10:57pm
Yes Bill, I know that the fenders are different, but I don't really have that much of an issue with the original Spirit fenders....
No one carries All Terrain tires in the original Eagle size of 195-75-15...
 
I'm running 205-75-15's and yes, they do occasionally rub on the fenders in a hard turn and bump...  Nothing major, and it hasn't damaged the tires or fenders yet!!
 
Yes, I had an Eagle donor and used the rear axle also to get the axle UNDER the springs....
 
Yes...  It's an automatic....
Yes...  I used the engine out of the Eagle...
 
I still don't understand your issue with the seats....
That was the easiest part of the whole conversion!!!
 
Lopped off a bracket and the seats fit perfect!!
 
 
Not sure that any of this is actually helping the OP...
It WAS about a Gremlin...  
 
Sorry about the hijack!! 
You Drive A What?!?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Jun/13/2019 at 12:06am
that's all pretty interesting to know.

but ebven tyhe hornets aren't compatible with other hornets. the factory probably viewed their chassis as stamping and systems, not complete welded assemblies as we must.

the '70 hornet has a lot of 68, 69 Rambler American in it, literally -- rear panels, gas filler system, various bits here and there. much if it does NOT interchange with 72, which was another engineering change leap. the 82 motor doesn't fit in the 70 hornet, the head hits the heater box. i made that fit with modification.

i personally like AMCs engineering because i (think i) understand their small-shop mentality of incremental improvement and make-do. they used a peculiar kind of engineering conservatism that is very 20th century American in approach. it's really evident in the Nash-to-AMC model changes. they fixed the most agregious problems first (the spectacularly crappy threaded lower arm trunnions), tried out things in funny places (1962 195.6 OHV aluminum engine hydraulic lifters are the SAME as 4.0 Jeep lifters 45 years later) and relied heavily on interchangability (not always wisely, i think, as products, but sure handy now for us hobbiests). i've bolted the damnest things into the damnedest cars.

the Spirit "looks like" the 1964 01 chassis if you squint at it. some stuff bolts on, some doesn't. lined up in a row (in my head, lol) you can see the progression of changes in the 01 chassis, AMC's most successful product, hands down. it spawned all sorts of good stuff for them.

the '68 AMX rear suspension is nearly identical to the '58..'63 American (even the shocks interchange). of course it's a fairly generic design overall.

what other manufacturer has a chassis that will accept every engine they made? 195.6, 199, 232, 258, 290, 304, 360, 390, 401, all more or less bolt into the 01 chassis.

i love hacking on AMC product.


1961 roadster american
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Jun/13/2019 at 8:50am
Originally posted by MacGyver MacGyver wrote:


 
I still don't understand your issue with the seats....
That was the easiest part of the whole conversion!!!
 
Lopped off a bracket and the seats fit perfect!!
 
 
Not sure that any of this is actually helping the OP...
It WAS about a Gremlin...  
 
Sorry about the hijack!! 


Don't forget the original post was NOT about Spirit, which is decidedly different than Hornet and Gremlin of the early years for each.

So, you are running with only three anchor points?

I know about Eagle - and their seats - it's sort of my specialty and has been for years.......... and I have done a detailed comparison on the seats. The bracket or mounting height is different due to different floors, the lower frames are different, BUT, the rest is mostly the same. For example, you can take the seat backs off an Eagle seat and put on a Spirit seat or take the Spirit seat BACK off and put it on an Eagle seat - assuming you are not trying to mix reclining and base model seats.

The mounting point you likely cut off is shown here - it mounts up inside the seat lower frame. So unless you put in provisions up inside the frame, you are using only three of the four mounting points. Doable but personally it's not where I'd go. But maybe you did mount a bracket up inside the seat frame to anchor it to the tunnel.

http://theamcforum.com/forum/eagle-sx-4-seat-comparison_topic21931.html





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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMXRWB Quote  Post ReplyReply Direct Link To This Post Posted: Jun/13/2019 at 1:04pm
Malatrix,Buy one of the many fine books on American Motors cars.They will explain in detail the AMC Eagle line.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Jun/13/2019 at 2:07pm
The basic engineering of the Hornet/Concord/Eagle (and likewise Gremlin/Spirit/SX/4) chassis/body is pretty much the same. Not identical, but similar enough it's usually not hard to make things work from one to another, with a few exceptions. There were some differences over the years and where things bolt on changed some, but with some modifications you can take most parts from one to another. NOT usually direct bolt-ons, though they are in some cases. Many small, incremental engineering changes as TomJ pointed out. You'll find those changes when you try to bolt something like a 74 front clip to a 71 body. The filler panels (like between radiator support and fenders) and many of the screw holes will have changed, but with a little effort you can make it all work. Not something you want to do for a restored car (again, with some exceptions), but for a driver where you're not concerned so much with being factory correct it's not such a big deal.
Frank Swygert
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