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Javelin
Javelin MegaDork
3/8/16 9:37 a.m.

You are probably familiar with the original build thread where I spent 5 years getting it running and driving and then enjoying it for cruises, shows, autocross, and drag racing. Then disaster, it caught on fire! The car was saved but the greasy bits underneath were toast. Then I flirted with unloading it to buy a 1969 AMX from my dad, but he ended up keeping the car plus the SCCA came out with a new class, CAM-T, and a decision was made. It was time to toughen up and just build the car, so starting in January of this year, I did.

Javelin
Javelin MegaDork
3/8/16 9:46 a.m.

First things first, the car had to get to the shop with the toasted rear axle. Wonder of wonders, it drove there!

The brakes were mushy, the rear end made awful noises, and the engine was grumpy, but it did fire right up and drive there.

Once up in the air and drums off, we found the culprit of the fire. The brake bar for the INOP parking brake had worked it's way loose and fallen onto the axleshaft, which created some heat and sparks. Then the wheel cylinder failed and dripped brake fluid on it, and that was our fire. It toasted all of the brake components on that side, but everything checked out fine... in the air.

Except for the front end. I had a trusted shop do the front end rebuild late last year (all new control arms with bolt-on ball joints, new bushings, endlinks, and strut rod bushings) but they somehow got the strut rods wrong. This allowed the strut rods to shift back forth over an inch!

Javelin
Javelin MegaDork
3/8/16 9:56 a.m.

For the front end we figured out that the strut rod bushing kit wasn't totally the same as OE. Their sleeve was an inch too long, so the nuts tightened down on it before the bushings. Once we trimmed the sleeves and turned the bushings around, everything cinched up like it's supposed to. Then we figured out that the idler arm and tie rods were smoked.

So all new inner and outer tire rods

and a new idler arm were purchased and installed. Since we had all of the steering components out, it was time to fix this cars #1 weakness for autocross, the steering box. The factory unit in my car was a 7 1/4 turn lock-to-lock box, which meant it took 1 1/2 revolutions of the steering wheel to go around a slalom cone. They did make a close ratio Saginaw box of 3 1/2 turns, but besides being really rare ($$$), you can't rebuild one into the other, so I'd have to eat a core charge ($$$$) on a new one. I found a 4x4 shop that had a customer that needed a "slow" box, and I needed his "fast" one, so a swap was pulled with a little cash from me (his was rebuilt, mine was original, plus the value difference period), and now I can actually steer this pig like a modern car!

Javelin
Javelin MegaDork
3/8/16 10:02 a.m.

As for the rear end, well that's a far more involved story. Thinking the issue was truly just the brakes, we installed all new wheel cylinders, hardware, shoes, the works. We went through 2 sets of aftermarket rear drums (they don't fit and are garbage, and that was the good brands!) before deciding we could turn my original drums. Everything seemed great up in the air, so we put it on the ground.

Burnouts commenced! But it was not to be, the rear end made a horrible metal-on-metal noise every half revolution of the axle. Once the weight of the car was on it, the bearings were bad enough to allow the axle to flex enough that drums rubbed the top of the backing plate. In short, my rear end was borked. Now the Model 20 is actually a decent stick, but this one is a 2.73 open, requiring a different carrier if I want different gears, plus the gears have to be setup in the rear end, so it has to come out no matter what.

So it sat. And it sat. And it sat...

Stay tuned!

NickD
NickD HalfDork
3/8/16 11:06 a.m.
Javelin wrote:

Oh, yeah, I forgot that the Dana-Spicer axles used the weird setup where the hub wasn't part of the axle itself, but splined on and used a castle nut. Unusual design for sure.

Glad to see the car getting revived and evolving.

FSP_ZX2
FSP_ZX2 Dork
3/8/16 11:21 a.m.

Moser engineering makes "conventional" AMC 20 axles...no weak keyways to worry about.

NickD
NickD HalfDork
3/8/16 11:27 a.m.

In reply to FSP_ZX2:

As I recall, he's tossing the Model 20 for a Ford 8.8"

Apexcarver
Apexcarver PowerDork
3/8/16 11:37 a.m.

Jav, if using a mustang 8.8 trac-loc look into the alternative packing order for the shims. Also consider going for a different diff, the trac loc wears pretty quickly in autocross use.

Dusterbd13
Dusterbd13 UberDork
3/8/16 12:24 p.m.

Mmmmm.....

New cam t project.....

I can't hotlink from the phone, but picture a picture of Homer Simpson drooling.

Happy to see it coming back from the dead.

FSP_ZX2
FSP_ZX2 Dork
3/8/16 12:33 p.m.
NickD wrote: In reply to FSP_ZX2: As I recall, he's tossing the Model 20 for a Ford 8.8"

I had suggested that in the original thread--use an Explorer one with the rear discs.

mazdeuce
mazdeuce PowerDork
3/8/16 1:21 p.m.

Glad to see this coming back together. We had 7 CAM cars at our last event. I think the CAM classes are going to be popular and fun.

Javelin
Javelin MegaDork
3/8/16 10:37 p.m.

Meanwhile a Ford 8.8" rear axle was sourced. This one is from a 1993 Ford Explorer, which is leaf spring like the Javelin, and has the shock mounts on the spring pads like the Javelin. It's also a drum brake unit because A: it's the easy button for adapting to my car's brakes and 2: the later disc ones suck! (They are solid rotor with an integral drum parking brake and a crappy sliding single-piston caliper with a screw-bore piston)

This will get me 28-spline axles, 3.73:1 gears, and most importantly, a working LSD! Notice also the aluminum P71 driveline that we will swap my 727 TF yoke onto (same u-joints) and have shortened and balanced. Tonight my buddy is measuring everything to see what has to be cut/welded. We are throwing the Model 20 in the scrap heap. I will be sourcing all new brake components for the new axle, and if I can scare up the scratch, an aluminum reinforced diff cover with a drain plug as well.

Once this is in and done, we will align the car for AX and hopefully be ready for the first event on 3/27.

SilverFleet
SilverFleet UltraDork
3/9/16 7:52 a.m.
freedomautotransport wrote: The initial project car purchase is the most important part of your hot rod, and a large part of how much you'll enjoy the car when it's done. The better the car you start with, the less you'll need to put into it. Conversely, the less you put into it initially, the more cash and sweat equity you'll need for upgrades. There is a lot to consider just like with any big purchase, so doing your research is of great importance. We're offering a list of 20 cars that are both affordable, and inspirational. (Please note that all our ratings are on a 1-to-5 scale.) Some are off-year models that come with a lesser price tag, and some are more plebian platform mates of more expensive models. You can get a car in decent condition for less money than the prime-year cars, or you can get a car in much better condition for the same price.

That said, I really want to do CAM-T in my Trans Am someday. And the 8.8 is a great axle. We have one in the XJ-R and it puts up with all sorts of abuse.

tuna55
tuna55 MegaDork
3/9/16 7:58 a.m.

Sweet!

Great axle choice. Tunatruck is envious of the new rear end whereas beforehand it was smug in its superiority to the model 20.

Javelin
Javelin MegaDork
3/9/16 9:37 a.m.
Apexcarver wrote: Jav, if using a mustang 8.8 trac-loc look into the alternative packing order for the shims. Also consider going for a different diff, the trac loc wears pretty quickly in autocross use.

It's an Explorer Trac-Loc, but same difference. It will be stock to start with, but yes, a rebuild with more/better clutches is probably on the horizon. Plus I will be drag racing it, on slicks...

Javelin
Javelin MegaDork
3/9/16 9:41 a.m.

Once the axle is in and buttoned up, I plan on running it as-is to see what the next deficiencies are. The too-slow steering, crappy gearing, and 1-wheel-peal (followed later by the always-slide because I welded it) made it such a crappy autocrosser that I couldn't tell anything else about it.

Front suspension is all stock (new) with KYB GR2's and the rear suspension will be all stock also with GR2's (and the axle swap). Both ends have been lowered about an inch or so. If there's not enough damping (likely) I may try to go to KYB Gas-A-Justs (easy button) or adapting some TRD Bilstein's (yes, really) from a Tacoma.

Dusterbd13
Dusterbd13 UberDork
3/9/16 9:47 a.m.

Look at S10 blazer bilstien as well. Pretty close fitment for the duster.

Stefan (Not Bruce)
Stefan (Not Bruce) MegaDork
3/9/16 9:57 a.m.

Considering the GR-2's aren't performance shocks, but OE equivalent replacements, I'd say you'll be buying Bilsteins or another solution in the not too distant future. Still it will be better than blown originals and you'll get to drive the car which is more important than perfectionism.

I was going to ask a Jeep buddy of mine about his AMC Model 20 stash, but I see you've solved that issue. BTW, if anyone finds an SX/4 for sale, he'd love to buy one. He's also building a Lotus 7 clone (original size and Kent powered) so he's a GRM'er :)

Apexcarver
Apexcarver PowerDork
3/9/16 9:57 a.m.

The standard way to make a muscle car handle, stiff springs and sway bars big enough to approach solid front axle conversion...

I think my mustang is running something like 1 3/8 inch front IIRC. (its a big fat addco bar) along with the stock rear, coupled with stiff springs.

But all that needs dampers that can actually dampen that much. You are right to start there, but go for a stiffer damper than you think you need as you will want to stiffen things eventually.

Another consideration, Bilsteins can (in theory) be rebuilt at home if you are brave and do some research.

Javelin
Javelin MegaDork
3/16/16 12:30 a.m.

Tonight we hoisted it up in the air:

and took the Model 20 out!

Javelin
Javelin MegaDork
3/16/16 12:35 a.m.

The Model 20 came out with no issues.

The Model 20 (R) and Ford 8.8 (L) sitting side-by-side really show you the differences. The ring gears and pinions are nearly the same size, but the Ford's 29-spline axles are monsters compared to the 28-spline AMC's. The Model 20 sat offset to the driver's side by about an inch, the 8.8 is off to the passenger's by 2-2.5". The face-to-face width is identical, the wheel cylinders are the same bore, and we should even be able to swap parking brake cables.

Javelin
Javelin MegaDork
3/16/16 8:51 a.m.

Next it was time to prep the 8.8 to go in. I had previously pulled off the NVH weight and now my friend Seth is grinding the spring perches off. The Explorer perches were 2.5" narrower than the Javelin ones.

That didn't go very well, so we broke out the plasma cutter and torched them off.

After which we had to grind down what was left of the perches and weld in the dips in the axle tubes.

Javelin
Javelin MegaDork
3/16/16 9:38 a.m.

Now we were ready to lay the 8.8 up.

It fits!

We used the Explorer mounts and u-bolts but will have to torch off the shock mounts and weld on the staggered mounts from the Javelin's original brackets.

The offset of the pumpkin isn't noticeable and it's actually way better for the driveshaft and exhaust routing, buying me clearance where things were really tight beforehand.

We used new perches that had 3 positions, but decided centered was best, let's put it on the ground!

Javelin
Javelin MegaDork
3/16/16 9:45 a.m.

Tada! The shocks aren't hooked up yet, but that it basically where it should sit. I may even have to bring the nose down a tad now.

Wheels fit fine!

That's where we stopped. So what's left? Well, we need to set the pinion angle and then weld the perches to the actual axle housing. The original driveshaft actually looks like it will be the exact correct length after using a conversion u-joint to put the Ford pinion flange on, so that saves a ton of time and expense having it shortened. Plus the aforementioned shock mounts, swap the parking brake cables, and fab up a center brake hose. Tighten, bleed, and double-check everything, and we should be golden.

I did hit a little snafu, the season opener is actually this Sunday, the 20th. Needless to say, I probably won't be making it. That's okay, as the extra 5 weeks will allow me to get the interior technically legal (carpet and passenger seat) and get the motor ready to go (oil change, tune-up, and fuel filter). We also may have a weak battery and/or dragging starter to deal with, ugh...

Javelin
Javelin MegaDork
3/16/16 11:11 a.m.

News this morning is that the actual talented welder (as opposed to my friend and I who are both hacks) should be out later this week to do the hard welding. Ordering conversion u-joint and brake parts now...

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