Thread: Project Sebring GT Spyder

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I thought it was time to get this thread caught up.

One reason it took so long for me to get started actually spinning wrenches was that I really didn't want to blow the car apart. I literally spent weeks trying to come up with a way to get all the work done with the car mostly whole. I finally decided that was impossible. The real decision maker was all the rust I was finding.

The body might be fiberglass, but the chassis is steel. When it was assembled, the builder coated it with what appears to be spray bomb undercoating and it was flaking off everywhere. The fact that it had spent many years in New Jersey on salty roads hadn't helped. It also looks like they put a lot of effort into sealing the joints where the steel and glass panels met, but didn't take into consideration that a roadster WOULD get wet inside. There were no drain holes in the floor and it looks like water puddled there at times for long periods. In addition, where the undercoating had pealed off the underside, rust was firmly established. Luckily, the steel is heavy and even where the rust looked really bad, it wasn't terminal. It was obvious though, that the steel needed sand blasting and painting.

Considering the rust and all the modifications that I want to make, I had to tear the whole car apart. That meant becoming something of an automotive archeologist and trying to decipher how the builder put it together in the first place. I did download an assembly manual off a forum site that is dedicated to these cars and learned a few things.

Here are some pics of the rust I found:







These look bad, but the steel is still very solid.

After several days and a few 2X4's, I was left with this:

Thanks Stovens. I'm thankful that she did so well.

Here are a couple of pictures of the front end I was working on. I bought a piece of software that allowed me to model the roll center and camber gain of various layouts. I thought I could do it with simple wooden models, but the changing relationships of all the pivot points made this nearly impossible. The program made it a lot easier.





The upper and lower arms were going to be longer than the stock MII parts. I made a wide simple A arm and used off the shelf Energy Poly bushings. The strange square U shape would have fit the width of the frame rails. I planned to add heavy gussets for strength. I spent a lot of time working out the details and getting the fab work to the point in the pics, but I think abandoning it was the right decision.



I also reamed the lower ball joint taper out to a larger size. There is a lot of debate over the suitability of using the Chrysler upper ball joint that fits the MII spindle as a lower BJ. The upper BJ's are used in nearly every aftermarket lower arm. I choose to be cautious and went with a regular lower ball joint, but it had a larger tapered stud. The one I used in my fabricated arms was a GM press in, but I'll be using a screw in lower BJ out of a Chrysler Imperial with the tubular arms. That should be plenty strong enough for my light weight little car!

Now, that's enough space wasted on things that I'm not using!

I could have built my own narrow control arms, but I had wasted a lot of time to build the ones I didn't use and there are lots of choices available in the aftermarket. I figured there was no reason to "reinvent the wheel" and started weeding through the ones I could find. The problem is that a lot of them are built in China and use thin .120 wall tubing. That might be OK for the upper arms as they aren't highly loaded, but the lower arms need to be heavier in my opinion because they support the weight of the car. Throw in some shock loading from the crappy roads we have around here and you could get into issues with the thinner parts. The arms I bought are from Full Tilt Street Rods. They use 3/16" thick tubing on the lower arms and have a large plate welded between the lower tubes for added strength and bracing. They also use the typical Chrysler screw in ball joints and the bushings are polyurethane. They are supposed to be built in the USA. I'm also eliminating the strut rods with A type lower arms.

One problem that I ran into during the installation was the construction of the MII crossmember Classic Roadsters had installed when the frame was built. It was made from formed and welded 11 gage steel. That's about 1/8" thick and is actually similar to the original part made by Ford. When you go to strutless lower arms, you have to weld in support tubes for the shaft that passes through the arms. The MII suspension has been in use under countless street rods and kit cars for something like 30 years (maybe more) and during that time the aftermarket has learned that the steel needs to be thicker if you eliminate the struts. Most crossmembers today are 3/16" - 5/16" thick to give plenty of support for the added load on the lower arm.





I didn't like the 2 piece lower tube setup that came with the arms. This might be fine with the heavier steel in newer crossmembers since it's pretty much standard practice for retrofitted arms in the street rod industry, but I felt I could make it better with a little work.



I went with 1 piece tubes that are 1 3/8" OD x 5/8" ID. These are much heavier than the supplied two piece parts and I added 11 gage doubling plates to the inside of the crossmember.





These plates were welded around their perimeter and plug welded in several places.



The holes for the plug welds were a pain because the rear of the crossmember couldn't be accessed with my drill. No one locally had a right angle drill to borrow or buy so I rigged up a small chuck for my air ratchet and used that. It worked , but it wasn't all that much fun! I will also be boxing the end of the crossmember when all the work is done.

Man! I can't believe it's been over 2 months since I last posted anything on this thread. I've been busy and got a lot of stuff done, just not as much on the car as I wanted. That always seems to be the case though. So I'll be "binge" posting until I get caught up.

There have been a few more changes to the plan. This car seems to be evolving more than any other project I've done. It's slowing progress down and costing more, but I think I will have a better car in the end. I hope so anyhow.

I had originally planned to go with Mustang II coilovers. These are the ones that have the barrel shaped spring that fits the MII coil pocket on top and taper down to about 2 1/2" at the bottom. The problem with these is that the special springs are only available in 4 spring rates in the short MII application and only 2 of those would be anywhere near correct for the weight of this car. I decided that I would be better off modifying the upper spring pocket to take a regular coilover.

Of course, I had this little epiphany after I had already made some modifications to the upper control arm mounts. I had altered them so that the front end had some anti-dive built in and to make the caster/camber adjustments with shims. The original setup on this car had no anti-dive. It also used the original MII method of adjusting the alignment by sliding the upper arm in slots.

While I was at it, I made the upper arm mount adjustable for height. This allows the roll center of the front end to be altered as well as the camber gain. By adding or removing shims from under the upper control arm mounts, you can alter the spacing on the control arm pivot points. This isn't normally something that can be changed on most cars.

My current ball joints are Moog parts, but QA1 has some racing ball joints that will fit my control arms and are available with different length studs. This effectively alters the length of the spindle and changes the angle of the upper control arm. All these things will change the camber gain and the roll center height of the front end. Will I ever use all this adjustment? I don't know, but it will allow me to experiment and see just how altering the front end geometry will affect the handling. Who knows, I might decide to auto cross this thing one of these days. The QA1 ball joints are also very low friction and rebuildable.

I built the upper control arm mounts with the ball joint centerlines off set for about 4 1/2* of positive caster. This saves stacking a lot of shims on one end to get the caster that you want in the first place.









Some of the welding is unfinished in these shots, but you can get the idea of where I was headed. The bracket in the first pic bolts to the top and is braced by the vertical plate. The upper control arm attaches to this bracket. By putting shims under the bracket, the spacing of the control arms can be altered.

Oh the other thing that really pisses me when people build cars like this is the placement of the rear vision mirrors, you wouldn't have a clear view of them sitting in the drivers seat so that makes them useless so they should be moved upto the doors where they were normally placed originally. They are the correct looking mirrors though and are becoming harder to find I believe unless the Chinese are making shitty replica's. Where I did my training many years ago in the Auto Crash repair industry we restored several of the 3000 Healeys and gladly only two Bug eye Healeys which only had the little 4 cylinder for a wealthy car collector.

Thanks for the interest so far. I've got a little done and have pictures. I just have to find time to write it up.

Bob - I'm going more radical than just narrow arms. The plan is to replace the whole front with a narrowed setup. It'll be my own Mustang II based design.

Whiplash - I'm considering some options for the windshield. I probably won't change it completely, but I think it can be made to look better. The end caps make it look too "heavy" and bulky. Hopefully I can make an improvement.

I like the "racy" look of the fender mounted mirrors, but, as you said, they are pretty much useless for what they are intended to do. I will be moving them to the doors.

Like the body style & wire wheels!

Excellent start to a rebuild thread. Love the story home and the diagnostic skils you have to deal with the problems as the evolved. I also am looking foward to reading this thread. I have a major soft spot for the old healys and have also always wanted one, but have run into similar situation to you of trying to find a runner and not a rotter that fit in my budget! Around hear they go for a premium!
I'm guessing you were looking for a spoke style wheel that would accomodate a wider type tire. Looking forward to seeing the mods as you go. But nice looking car as it sits. Please post some more shots including the engine compartment.

Here is a very high priced one
1962 Austin Healey 3000 MKII TriCarb Two Seater BN7.

Anyone that has remodeled anything will tell you that you always find things you didn't count on. This car was no exception. While the welds and engineering that the kit company did were not bad, the things that were built by the assembler were not so OK. My dad was a welder most of his life and he would have said these welds looked like a buzzard puked them up. Some weren't even partially burnt in. Some of the pieces just fell off on their own during disassembly. In addition the assembler's "engineering" left a little to be desired.











All of this will need to be redone, of course.

One thing good that came out of all this is that the chassis actually seems to be much stiffer than I had originally thought. I believe the flexing I was feeling is actually due to bad assembly in the cowl area. The original engineering was a little light in this area and I was getting a bad case of cowl shake (the Brits would call it scuttle shake). Not an uncommon issue with convertibles and something that I think can be remedied.

After the tear down, I went in to "mock up" mode. Building a car is like playing chess, you can't just think about one thing at a time. You have plan many steps ahead. If I had a CAD program and more importantly knew how to use it, I could have whipped up some trick drawings in the comfort of my easy chair. Since I'm a 20th century neanderthal, I had no choice but to get my hands dirty.

One thing that had been worrying me was the transmission. The car had a T5 overdrive in it when I bought it, but being a non-world class trans, I was concerned about strength. GM never put the T5 behind a 350 for that reason and I was going to a 383. I found a T56 (6 speed) out of a 90's Camaro. Besides the extra OD gear, they are stronger than the T5. The only problem is physical size. They're much larger than their 5 speed cousins. I wasn't sure if the trans tunnel was big enough to take the new gearbox so I dropped it in to see.

It's a little tight, but I was pleasantly surprised to see that it fit just fine. There is one small area where the reverse lock out solenoid contacts the tunnel, but that can be fixed easily. You can see the small round projection on the left in the picture contacting the tunnel.



Even the shifter location was close, but I'll have to see if that works OK for my wife. I may need to relocate it further forward, since it's pretty far back and she needs the seat closer than me.

Another thing I needed to do was cut the new rear end down. I picked up a 1999 Explorer rear at the local U Pull It. For the money, it's hard to beat them. For $130 bucks I got 3.73 gears, Trac Lok limited slip, 5 hole axles and disc brakes. To convert the 8" that came in the car to all that would have taken about $700 - $800 and it wouldn't have been as strong. It would have been lighter, though.

The main problem is the width. The stock Explorer rear is 59 1/2" long wheel flange to wheel flange. I wanted something around 54". This would give me plenty of clearance for any reasonable wheels and tires I wanted to run. This should let me go as large as a 275 width tire on an 8" rim with 4 1/2" backspace and still get it under the fender lip. The wheels and tires I have planned are not quite that big, but it gives me future options.

The other issue with the Explorer rear is the large offset pinion. It's several inches to the passenger side and I needed it pretty much centered.

I bought some shorter axles from Dutchman axles. I ordered them with a 1" difference in length since this would center the pinion.

You can see the offset in this pic and that it's pretty long.



I cut it down with a large pipe cutter. It works just like a smaller tubing cutter, it just takes a lot more muscle!



Here is the new width with centered pinion.



Now before anyone says that it's not straight, it's just mocked up and tacked together right now. I'll line it up perfect and weld it up after I decide where the link brackets will go. Also, I have to make all the bushings to run the line up bar through.

Wow, there sure were some "surprises" in there. You're making some great improvements that'll turn this one into a great ride.

Yikes! Those were some pretty scary welds and patches.Good thing your able to tear it down and shore it up! X2 on the progress.

Wow, great adventure and what a cool car! You definitely don't see them very often. I like your new ideas and look forward to you improving this sweet little ride!