setting an AMC on kill

so, im the chassis guy, and team leader for the $2017 challenge team. car we are using is a 1980 AMC spirit. was a factory 6 cyl/4speed DL.

its first foray at being a challenge car was 2007. project snowballed, became an engine swapped daily, and was eventually wrecked pretty hard. took a parking berm to the engine crossmember hard enough to eat the oil pan.

anyway, I bought it as a roller/parts car/ scrap metal candidate.

looks like it can be saved with a new crossmember, and some sweat.

the car is currently still equipped with addco 1 1/8 front sway bar, 1 inch rear, 1 full coil cut from stock springs, KYB gas Adjust shocks, prothane poly bushings throughout, and the isoclamps removed in the rear. newish ball joints, steering linkage, brakes, etc. im estimating about 20k on all these parts. 15x7 mopar steel wheels with JUNK 235/60/15 tires. badly leaking and worn power steering box.

the general plan for the car is to simplify and add lightness, and then hit it pretty hard with the horsepower stick. as the chassis guy, I personally think my job is the most important, but because, according to the rest of my team, "its already done once its unbent!"i have no real budget to work with. $250 tops. not including tires.

so im trying to figure out what to do, for the best bang for the buck. labor is free, im a fairly decent fabricator, and its NOT going to be a street car. ever. full on dedicated, rule-less autocross/track/drag car.

my thoughts, having NEVER messed with an AMC before, are as follows:

1. seam weld new crossmemeber.
2. box upper and lower control arms.
3. cut the end off the lower control arm, plate it and put a bung in it, and use a heim joint to eliminate bind and open up more alignment options.
4. toss bent strut rods, make heim jointed and adjustable replacements for independent caster adjustment.
5. cal track bars, or slapper bars for the drag portion.
6. 26X8X15 bias ply circle track slicks on the steel wheels.
7. jeep grand Cherokee steering box for quicker ratio
8. seam weld engine bay, add subframe connectors.
9. add another leaf or two to rear springs for more rate
10. build montecarlo bar/engine bay brace for engine bay, possibly using drivetrain as stressed member.

what low hanging fruit am I missing? should I locate and run taller ball joints like I do in the GM stuff? relocate the upper control arm pivots like we do with the early mustangs?

what is bumpsteer and camber gain like in these cars?

so in short, what works and what doesn't when you're trying to set up an AMC on "KILL"?

Hi, I entered an AMC Spirit in the $2014 challenge. I didn't have time to mess with any of the suspension but I can pass along some measurements and some other info. The AMC camber gain is terrible. Think it actually goes positive if i remember correctly. I welded up the holes in the stock upper arm and drilled it for a 63-71 GM truck ball joint which was an inch taller. Still even with that the camber gain was bad. At that point my thoughts were just try to get negative camber and deal with the curve. I was either going to add material to the crossmember so it could be redrilled to move the arms out more or modify the arms for heims like you mentioned. Plan B was to move the upper control arm mount and build a custom upper arm to change the geometry but that was going to take a lot more time, effort, and budget.

Stock steering box is 4-4.5 turns lock to lock. For autocross is was terrible. GC box or any GM fast ratio would be a huge improvement. I'm going to be running a Trans AM WS6 box.

Some random info that might help:

Upper ball joint taper is 7 degrees which is the same as early GM and Ford Pinto/Mustang II.

Top of the front spring is 4.5" OD.

Stock rear axle width is 57.5" Ford Explorer 8.8 is 59.5". One side of the Explorer axle is 3" longer then the other side. If you shorten the long one and run 2 shorts axles you will be at 56.5". With the disc brakes you are then pretty close to stock width.

Car weighs 2833 lbs with a turbo 4.0L, no A/C, and full interior.

Suspension calculator that should help figure out the camber curve. http://www.racingaspirations.com/

Link to my $2014 build. Hopefully the car will be back in 2017. https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/1982-amc-sprit-challenge-build/78512/page1/

I wouldn't bother with the seam welding. Waste of time. On a car that will be raced over an extended period of time it may be a benefit as the chassis will stay together but for the 2017 Challenge I don't see any benefit. I've seen this done to pro rally cars but not road race cars. In most cases it's not allowed until you move up to SCCA level Production class racing or GT level. And those cars can or are mostly tube frame so the stock chassis are not an essential part of the "working" chassis.

Also it won't stiffen the chassis that you would notice.

An engine bay brace is easy and will help. Sub-frame connectors will also. Adjustable caster is always a good thing. Adjustable camber is too. Boxed control arms will as well.

Getting back to seam welding. I have found that most cars have some type of sealer in the seam where the panels are spot welded together. When you try to weld the seam up you will almost always get some degree of weld contamination due to the sealer reacting to the heat of welding. Even if you clean the metal to bare steel the sealer is still there between the two panels waiting for you. Spend your time on other "go fast" mods.

after this thing was rust repaired and then wanked on a concrete barrier, I figured that seam welding wouldn't hurt. also, near as I can figure, its nearing the 300k mark, and pretty flexible. after the challenge it will probably get a cage and a log book, so...

seam welding is free as far as the challenge goes. seems prudent. im also planning to sandblast the engine bay, under carriage, and interior prior to welding to reduce the amount f weld contamination. however, my welds will be inherently contaminated at this point because im a E36 M3ty welder. I weld best with my flux core. so....

psudosport: I love this place. a fellow competitor, with the same chassis, is offering setup advice and hard won research and knowledge. thatnk you!!!

were hoping to get the wight down to about 2400lb with driver. we figure SBC is lighter than the original 258. lexan in the hatch glass, no interior, no wipers, no bumpers, no HVAC, no undercoating/sound deadening, and extreme weight management of everything else will get us there for essentially $0.

with the front suspension, id expect that a taller upper ball joint would cause more camber gain, as well as a lifted ride height. thanks for the thought of extending the LCA as I convert to heim.

hw did yours actually autocross? ive never actually driven one of these, and vaguely remember riding it it once before being totaled.

I'm told that some grand wagoneer axles are drop-in, but never had a chance to confirm it.

You'll need to inspect and possibly reinforce where the rear spring shackles mount into the chassis, they're known to bust through the floor if badly rusted.

Also inspect where the subfloor cross members go into the inner rockers. Should be easy to see, most of these cars don't have much rocker panel left.

Pulling fenders is a pain as they're welded in the top corner by the windshield. If you have the ability to make fiberglass panels for cheap, they are also damn heavy.

theyre welded? where? because im planning on pulling them to keep from damage, and make life easier. will check for rocker rust. also, any examples of the reinforced spring plates?

Top corner by the windshield. If it is welded, it's on the outer surface. Not sure if that's true with spirits, but it was on my sx4

I'd heartily recommend a Ford Explorer 8.8, see my Javelin CAM-T build thread for more info. For the small-body, you will want to shorten the longer tube and run 2 short-side axleshafts. Should be able to get everything in the junkyard for dirt cheap. Just buy 2 complete axles, then you can "rebuild" the clutch-type LSD with more plates/discs, plus have a spare set of brakes for when the discs/calipers fail. While you are down there, try to use the Explorer rear sway bar, and make some slapper bars. I'd really want to run a panhard bar, but there's like no room back there once you have a tank, exhaust, and staggered shocks going on.

For the middle of the car, definitely do subframe connectors. Some straight flat steel should be all you need as the small-body front and rear subframes line up. Make sure to put reinforcement plates in the floor for your belts as the floorpans are pretty thin and flexible. Can you get a rollbar in it under budget?

On the front, work with the stock stuff. Leave the upper a-arm alone except for the GM ball joints. Some flat plate steel and a drill press is all you need to make some lowering plates for the front (though I personally hate them because it puts the bolts in double-sheer, but I've also never seen one come apart so...). On the lower arm, box in the bottom, and then cut off the ball joint in and extend it out 1", that should correct the built-in positive camber and get your camber curve more in-line with modern stuff. I wouldn't mess with the steering components beyond the quick-ratio box. I have a 75 Trans Am WS6 box, but any 3 1/4 turn box will work, even the later 3-bolt saginaw ones (though you might need some fitting adapters).

Front spring rate will be hard because of the odd AMC size. You might be better off finding a cheap set of coilovers for anything else and modifying the AMC to make them fit. The upper shock mounts unbolt from the towers, so it's pretty easy to make whatever upper mount you need including for height.

Front shocks are 9.09" compressed and 13.5" extended, 4.41" stroke with an S1 upper mount and the wacky studded lower mount. Front springs (from a V8) are 5.02" ID, 0.685" diameter wire, 9.5" installed and 14.38" free height with a tangential and a pigtail end. Stock V8 spring rate is 307 lbs/in constant-rate.

Let me know if you need any more information or parts measurements, I have 2 complete AMC suspensions spread out in the garage trying to get everything figured out for my car.

As far as power goes, the SBC doesn't fit the AMC bay very well. It ends up high and too far forward unless you have the crossmember and firewall. The SBF actually fits nicer than the AMC V8 and get sit down nice and low and pretty far back, plus the trans tunnel was designed for the T-5, so it bolts in on the trans side.

If the front camber curve is that bad, you need it as stiff as you can.... My Alfas are like that, and they needed huge stiffening to cure bad understeer.

For the rear- can you add an upper trailing link? That will help prevent axle wind- and help locate it better to put power down. Actually, didn't Shelby add both a panhard rod and an upper link to a leaf spring Mustang?

What do you mean by crossmember and firewall? I'm fairly familiar with the sbc, but open to bettef, lighter, and easier options.

And thanks javelin. Panhard bar may be added to the build. Because exhaust is optional.

Can you fit standard 5 inch coil springs up front? Because dirt track parts are cheap.

Also, if extending the lowers, what snowball effects should I anticipate?

In reply to Dusterbd13:

Crossmember is usually in the way of most common SBC oil pans. Stock AMC pan has a rear sump and it's WAY back. Because of the rear distributor in an SBC, you either have to screw with the crossmember and pan, or cut the firewall out to swap one in. SBF literally falls into place. Use stock trans crossmember and mount with a Mustang T5, the stock 5.0L tubular manifolds fit, and no firewall cutting. It's just a way easier swap.

I have some 5" circle track springs to try in mine, the problem is they are all really tall compared to the AMC stuff. I'm loathe to try hacking 4" off of a spring, but it might work for you.

On the lowers, you'll have to watch your upper ball joints (but you are also modifying those...) and go through full range of motion on the steering both compressed and extended to check for bind. IIRC, the outer tie rods might need a tweak to keep everything clear.

Cool. Thanks.

And you may have pushed me over the edge to ford. That is what was in the car last, and there's already some swap parts in it for that.

Now to find a good one....

Let me know how the 5 inch coil works.

And, any links on the lca lengthening?

woah...a dozen posts in, adn this thread is already doing great things... I have nothing of value to contribute, just wanted to give a hearty attaboy.

In reply to 4cylndrfury:

Agreed. I'm going to have to link these when I start the build thread.

Here's some great shots of the Ronnie Kaplan Engineering Trans-Am Javelin from 68.

Notice all the steering components are stock and the front sway bar is, too!

Very top left of the image is the RF LCA's reinforcement plate on the bottom.

LCA from the rear of the car looking forward. Notice that they boxed all the way past the ball joint and had to make an access hole for the castle nut. Notice also no lowering plates.

Rear end. Notice the reinforcement bar going to the frame attachment point for the panhard bar.

Rear end side of the panhard. Notice how far out that thing sticks! This would never fit with a stock tank. This car has a fuel cell in the trunk. Notice the sway bar is above and ahead of the rear axle. Staggered shocks, too (which the Spirit should already be).

on outs, the shock mounts to the UCA. does this mean that its a different suspension? or did the trans am cars relocate the shocks?

the panhard bar may be tough to fit. especially since we are planning to retain stock tank. when I get this thing on the lift, ill see what the clearance situation is.

and I love the side pipes on this. may have to do that on the AMC since the tailpipes were cut off the exhaust when the car was gutted, and have since gone missing.

The shocks are not relocated, it's a 68 so it has trunions up front. The lower half of the suspension doesn't change, just the UCA, shock, spring, and upper ball joint. The shock moves to inside the spring in 70.

In reply to Dusterbd13:

You could also look at a Mumford link if you're that tight on room.

Finally found a pic of an extended LCA!

Is there any reason, other than simplicity, that I couldn't extend the bushing end for the same effect? I figure, based upon highly accurate eyeball and no real measurement, that a 1x1 square tube could be inserted and welded, adding the inch and heim joints at the same time. Why wouldn't that work?

In reply to Dusterbd13:

Because then the strut rods won't bolt on.

Well damn.

Would it cause Tire interference being further out? I'm already plotting adjustable heim joints and tubing in place of the bent factory parts.

Also, apparently a pair of spirits race and won the ring back in 78. Found tons of info on the race, but nothing of the chassis setup. Any ideas?

I don't know. I've never seen or heard of any AMC LCA to ever be lengthened on the bushing end. A longer strut rod would also have a different angle to it, your sway bar attachment points would have to be re-drilled or a longer bar installed, and the angle of the LCA would be steeper. By doing the ball joint end you don't change much geometry beyond static camber as that portion of the LCA is after the bend and parallel to the ground at ride height. By lengthening the bushing side the ball joint would now to be angled up past horizontal at ride height (ie - pre-compressed). I imagine that would cause the same issues as hacking the spring really short to lower the car, probably increasing bumpsteer, making the camber gain/loss curve even worse, and putting additional wear and pressure on the tie rods. Theoretically you could shallow-out the bend to make the ball joint level again, but then you're probably weakening the LCA and will have to reinforce the sides and box it heavily.

Dusterbd13 wrote: Also, apparently a pair of spirits race and won the ring back in 78. Found tons of info on the race, but nothing of the chassis setup. Any ideas?

The class they were in was heavily stock-oriented and they ran BFG street tires. When the #2 car was found, restored, and sold they found the front suspension stock with adjustable Bilsteins and screwjacks for the springs. The rear was completely stock except for the shocks.