Thread: Project Sebring GT Spyder

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Mike, I really appreciate your explanations of the thought processes you go through, your talents and the solutions! I predict that for this one, at some point you'll overhear some guy talking to his buddy or his girlfriend at a cruise or show, saying "Look at this, the guy put his wheel spacers on the wrong side!" The things you hear when parking lot "experts" are "explaining" things....

I'll agree and echo Mr. Spears thoughts in the first sentence. But, now I'll have to sit and be patient for you to take it for a ride and then give us a report on your findings. Ackerman =YES? or NO? You've got so many nice features built into this chassis, should be a blast to drive.

Thanks folks. I really appreciate the words of confidence.

I will report back on this, good or bad. I've put too much time, money and effort into this thing to just live with something that doesn't work.

BTW - I may have already figured out a way to "fix" this without a custom rack. It would involve machining extensions for the rack main shaft to space the inner tie rod ends out 1" on each side. I'm sure this wouldn't be as simple as it sounds, but I think it's doable and a lot cheaper than buying a custom rack. That's a nice little thinking problem for a later date. Gotta finish this thing first. Debugging (which is ALWAYS required) can come later.

With the basic alignment behind me, I mounted the front brakes. As I said earlier, I’m using a Baer brake kit designed for the Wilwood Pro spindles. They are 4 piston calipers with 11 inch rotors.

I considered both Wilwood and Baer kits, but settled on the Baer’s because the rotors are so much heavier than the Wilwoods. The Baer’s are 1.02 inches thick while the Wilwood’s are just .810. Other than that, the 2 kits were very similar. Both would fit under 15” wheels and had the pistons sealed against road grime. The Baer tech I spoke with assured me, that considering the light weight of this car, I could do track days with just a pad change.



While I was at this stage, I also went ahead with the flex lines and a little plumbing. The hoses are -3 Russel DOT approved parts. It took a little fiddling to come up with a hose routing that would allow full suspension travel and steering without rubbing or kinking, but eventually I got it worked out.

I prefer hoses with female screw on connections on both ends, rather than the hoses that have swaged on banjo fittings. The screw on hoses are usually a little cheaper and they are easier to fit, IMO. You can put a slight twist in the screw on hose to get it to clear things whereas with the crimped on banjo fittings, you pretty much can't do anything except bolt them on and hope you have clearance.



I also did the front crossover line. This needed to be done before the engine goes back in. Trying to route the line with the engine in would have been much more complicated. Because I had plenty of room to work, I was able to do it in one continuous piece.



It made sense to finish the short line from the line lock valve to the front tee while I was making the crossover.

I am currently focusing on things that need to be done to get the engine and trans back in since I need to get the car off my lift. I have to help my grandson put a new (to him) engine in his truck and I need to pull the trans out of my 46 to replace the flexplate. I don’t want to do either of those jobs laying on my back, but there was one thing that needed to be finished on the rear end before I moved on.

One of the things I got back from the powder coater in the last batch was the rear sway bar assembly. I had to wait until the rear suspension was back in to finish the parts. I didn’t have time to do it before I sent the frame out to be coated.

I originally wanted to mount the bar under the rearend, but that wasn’t really possible due to the exhaust. I had to mount it on top and there is just enough space for it with the body on. Changing it will be a pain, but that’s the way it goes sometimes. The available space dictates what you can do.

The bar itself is a 26” torsion bar intended for a mini sprint car and it just squeezes in between the frame rails. The ends are 1” splined. This bar is ¾” diameter and gun drilled. It is in the middle of the available diameters. The nice thing is, the ends all stay the same, so all you have to do is swap the bars.



The arms do look a little chunky, but that is due to the size of the weld on splined ends that were available. That and I just happened to have the tubing that fit them. They are actually not as heavy as they look. Considering that they will be buried way up under the body, I doubt anyone ever sees them if they are not reading this thread.

The bearings are Delrin bushings that are made for these bars and are off the shelf items. This should make it easy to get cheap replacements in the future. I fabbed the steel housings for the bushings and added a grease zerk. They will get silicone grease too.

This is before powder coat and may be a little easier to see.



The end links were modified from some type of side by side suspension struts. I have a friend that was doing some R and D work on an electric 4x4 side by side a few years ago. I was at his shop one day and noticed a big box full of these struts. He gave me a big handful of them saying that they might come in handy one day. They worked just fine for this job.

I bushed the large metric hole down to 3/8” and changed the button grease fitting over to a standard zerk. Because they are so heavy duty, these rod ends should last the life of the car!



The links are different lengths because they attach to the Watts link brackets on the rearend and of course, they are different heights.

I totally forgot to send the lower link brackets to the powder coater, so they will have to go in the next batch of small parts.

Since there is no poly or rubber in the sway bar assembly, there won’t be any lost motion in operation. That should make the bar more effective, but it might make the ride a little harsher.

OK, gang. I found several things that I wrote up quite some time ago and never posted. I was sure that I had put them up and went back and checked the thread, but didn’t find them. Sooo, while I’m busy on getting the engine back in, I’m going to post the stuff I found. Keep in mind as you read them that this was all done months ago. The pictures and wording may seem out of order because they are. At least it will give ya’ll something to look at.

Just for a time reference, these posts should have been made after I got the LeMans style gas cap on and right after I took the first batch of parts to the chrome shop. This stuff was done sometime between March and August of 2020. This was during the time my company sent me home to separate the workers due to Covid and it was crazy thrash time for me trying to get the chassis to powder coat. Guess this stuff just got lost in the shuffle. I’ll post the up a few at a time to give folks time to read them. So here goes.

I also found another set of seats and fitted them. The original seats I used were out of a 1995 M series Miata. They have separate head rests (all other Miata's have one piece headrests and seats), fit the car well and look fairly period to the car. However, mine were in bad shape due to weather exposure and I was missing the Mazda seat adjusters. I added some universal adjusters, but they were just ok. The seating was pure sports car in that I was sitting pretty much on the floor with my feet stuck straight out in front of me in semi reclining position. As my back condition has worsened, this position became unacceptable. I doubt I could have ridden like that for very long. I needed a fairly upright position with a little drop to the floor. It was obvious that I had to change something.

I also found out that the M series Miata's were sold in very limited numbers in the US market. The only padding and upholstery rebuild stuff I could find came from Europe, where they were much more common. I had the choice of either getting custom covers made or getting a kit from Germany by way of the UK. Either choice would cost north of $600.

While I was delivering the parts to Tennessee for chrome, I found another set of seats out of an MX5 with a retractable hardtop. They are black leather and the top had protected them very well. There is one minor scuff on the leather that can be easily repaired. I got both seats and tracks for $300. They are much more comfortable on my back and have better bolstering for lateral support. They are not as period looking as the old seats, but I'll make that sacrifice for better long range comfort.

Here are the new seats:

I also wanted to get some more leg room. I had already pushed the firewall forward a few inches and that helped, but I still felt cramped up. I would have to move the seats back to gain anymore. I needed to do some modifications to fiberglass section behind the seats anyhow, since after I got the body sections aligned, the rear bulkhead section wouldn't touch the floor.

If you've been following along since the beginning, you will remember that I found the rear body mounts were bent down and I straightened them out. I thought this was due to the rearend taking a hit since the bumpers and brackets were bent like they had been in an accident. I don't think this was right. The car had obviously been hit in the rear, but I think that whoever built this car ran into this same issue and bent the mounts down to get the rear section to touch the floor pan.







Before I could work on rebuilding, I had to get rid of more of the same "horsehair" looking crap that was used as insulation on the firewall. I don't know what type of silicone was used to glue this junk down but it doesn't give up easily. Once again, I had to resort to a stiff wire bush on a grinder to even touch it. It was even better bonded to this part than it was to the firewall.





Eventually I got it clean enough to work on.

The first thing I had to do before getting the seats in, was patch the holes I had cut in the floor to access the new rear suspension mounts I welded on earlier in the build. Not much drama here. Just straight forward pattern making and welding.





I bent a lip on the rear of the patch for a little extra strength.









You can see how much extra length I added to the floor here by the notch in the foreground. The vertical leg of the notch was where the original floor stopped. This notch was filled too, but I didn’t get a picture. This may not look like much extra room, but, every little bit helps when you're talking about leg room.

Here you can see the extra room that Classic Roadsters left behind the rear bulkhead. I’m not sure why they did this, unless it was to have the rear floor follow the contour of the laid back seats. What it did was waist a lot of potential extra room. I could fix that by changing the angle of the rear bulkhead and tieing it into the little extra floor length I had added.



I also had another issue to correct. The wider wheels were contacting the inner interior tub. They bolted on fine and appeared to fit, but when the suspension was articulated, like one wheel hitting a big bump, the tire would just contact the body. I could fix this by adding a tiny wheel tub. This would allow me to keep as much interior space behind the seats as I could. Besides, trying to go bigger with the wheel tub would cause issues with the fuel tank. I was about as deep in the wheel well as I could get without major surgery.

This is looking up where the tire was contacting the body tub. Not much contact, but any is too much.



Here you can see how much I had to cut out to clear the tire. You can also see the big hole I had to cut to clear the new wider seats.


This shows the clearance I gained by relieving for the tires.

Getting this stuff posted hasn’t been as easy as I had hoped. I switched computers a few months ago and some of the pictures got lost or jumbled up. I’ve had to hunt them down to upload them. Here are a few more of the old stuff.

I suppose I could have dummied up some kind of form and laid glass over it to reform all this stuff, but as I said earlier, I don’t particularly enjoy working with ‘glass. Besides, building the form would have been almost as much work as building out of metal and I would have still had to lay up the fiberglass, smooth and paint it.

Of course, that meant that the new metal parts would have to be riveted in or panel bonded to the fiberglass with adhesive, but that wasn’t a big issue. I decided to just rivet them in and seal the joints. If I have trouble with the rivets loosening, I can always use one of the new panel adhesives to bond them in. I think with enough rivets, this won’t be an issue. Since I would be installing a bunch of pop rivets, I went to Harbor Freight and dropped a 20% off coupon on pneumatic pop rivet gun. Man, it sure does make things quick and easy.

By riveting all these pieces in I could assemble them in sections under the car and I also had the advantage of being able to remove them easily if I ever needed to. Not sure if I would ever NEED to do that, but at least I have the option, and considering how difficult the rear shocks are to access, that option might come in handy one day. Also, the upper link mount is behind the seat bulkhead and that might need some kind of attention one day.

There was one small tool I had to make before I could tackle the sheet metal. That was a tipping wheel for my bead roller. I had to make some odd bends on a few parts that I couldn’t do in my brake. The tipping wheel makes this a lot easier than trying to rig up something on my welding table to do it.

I welded a hub onto a piece of steel plate that was actually an old slug from a hole saw. I almost never throw those things away, since they come on very handy. The hub was some kind of mystery alloy (probably 4140), so I had to bury it in a bucket of oil dry to keep it from cooling too fast and getting brittle from the welding heat.







Then I machined it up and here it is in action. I also made both a steel and a polyurethane “anvil” roller for it to pinch the metal between. I machined a recess in the die and made a custom flush mounting washer that would allow me to tip the flange almost to a 90* bend. I could finish it up with a hammer and dolly. The tipping die also has the advantage of being able to tip curved flanges.

There were many small parts required and almost all of the small angle tie-ins had to the curved to fit the existing fiberglass panels. I used the shrinker and stretcher for these. When these go in for the final time, they will get a bead of silicone to between them to seal the joint. I also have some brush on seal sealer that I may use. All of the metal and fiberglass will eventually be covered in marine carpet, so the pop rivets won’t really be seen. Some of the parts were welded together.

I made all these parts out of 18 gauge steel. I had it on hand and I feel a little better having steel between my back and the tire. I rolled a few beads in to give it a little support.
This is the bulkhead that goes behind the seats.





This is the finished inner tub and the filler panels for the seat clearance.





The parts that you see in the interior are only a small section. They are actually the inner fenders, too. I made some aluminum extensions to tie the steel parts into the outer fiberglass body section. A rubber lip seal will attach to the edge of the fender and press against the body to seal out road grime.







I made the fenders in two parts like this because I’m thinking of adding wider rear fenders in the future. There is a company making body parts for this car in limited numbers. The MX version of this body had fenders widened an extra 2” or so. I’ve talked with the owner of the molds and he says he can do just the outer rear quarters. This would get me the wider rear body kit and allow for wider tires. If I do decide to do that, all I have to do is remake the outer sections of the fenders that tie into the body contours.

Very nice work there!

Ditto Nice work, and glad to see your working on this, I'm doing carb work on mine today!

Thanks for the kind words, guys.

OK, gang. Just a quick update. I’m still posting the old stuff, but thought I would let you know where I’m at currently. I just got word that my paint guy has an opening in a few weeks and have decided to get the body painted now, while I can. This has shut the chassis work down for a while so I can concentrate on the body work and prep. By doing this, I can avoid having to tear the car down again for paint. I had originally thought about driving the car in primer for awhile and then painting it, but the more I thought about it, the less I liked that idea. I’ve been working on this thing for so long that when I finally get it finished, I’m not going to want to tear it back apart for paint. So, I might as well go ahead and do it now.

FWIW – The engine and trans is back in and most of the plumbing is done. I’ll get that stuff posted when I run out of old stuff. Now it's time to go attack some more itchy fiberglass. Back to the old stuff.

The MX5 seats mounted much differently than the old seats, which just bolted flat to the floor. The MX5 seats had flat mounting legs in the rear, but the front mounted top a sloped section on the Miata floor. I duplicated this (more or less) by adding an angled piece of flatbar across the floor.



The rear legs had locating dowels made into the mounting holes that keyed into the original Miata floor. I decided to keep those since they would help keep the seat in place in an accident and help keep the seat track aligned.

To duplicate the mounting hole in the MX5, I machined some counter-bored bushings that I welded to the floor. The front mounting bolts got some machined aluminum washers that better fit the mounting holes. Of course, I mounted the seats back as far as I could get them, which was the whole purpose.



As with any hot rodding, there were a couple of consequences from moving the seats backwards. The first one was that the emergency brake handle was too far forward. This wasn’t TOO hard to correct. I just had to install some more nutzerts and redo the cable adjuster. No real drama, just time consuming.

You can see just how much I gained with all this work. The forward holes are the original mounting location for the E-brake handle. That’s a lot of extra room when you’re talking about leg room. You can just see the seat mounting parts in this picture. Sorry for the crappy picture. I hunted through all the old pics I could find and this is the only shot I could locate of the seat mounts.



On to the second issue and this one was a biggie.

I had set the seat/steering wheel relationship to fit me during the initial installation, but when my wife sat in the car with the seat adjusted so that she could reach the clutch properly, the steering wheel was too close to her chest. Of course, she IS a little vertically challenged! I’m not allowed to use the “S” word!

I had originally intended to use most of the steering column from the Chevy Equinox that the electric steering unit came out of and just add a simple top section to dress it up. This was the original setup.



It was obvious that plan wasn't going to work. No amount of fiddling with the column position resulted in a location that felt right to both of us and I wasn't going to let her drive it with the wheel too close. Sooooo, I drug (dragged?) out some more of the junk that I've collected over the years and went to work.

At a swap meet, somewhere many moons ago, I had picked up a tilt/telescoping GM column out of a C4 Corvette and it had been kicking around the shop for a while. It was a little loose in the tilt joint and I remember it was cheap because of that. Most folks don't want to tear into one of these columns, but they aren't really that bad, just a little fiddly. I repaired my first tilt GM column back in the 70's and have been tinkering with them in various projects ever since. For the most part, they are all the same inside.

I cut this one down as short as I dared, repaired it and fitted it to the Equinox power unit. Luckily, I have a big box of assorted column parts as well as a few old column tubes and shafts stuck back from previous jobs. The real tricky part was getting the ignition and dimmer switch operating rods cut down and bent to fit and operate reliably. I had to take it apart so many times, that I made a couple of undersize tilt pins to keep from wearing out the holes they go in. The pins are hardened steel and the tilt knuckles are die castings. The pins are a press fit and it doesn't take a lot of abuse to stretch the pot metal knuckles.

This is the "tool" I made at least 30 years ago to compress the spring under the lock plate in a tilt column. When I was younger, I would find a big helper and have him push the plate down far enough to remove the retaining clip, but it definitely works better with the tool. I did have to add a couple of square tool bits under the tool because the legs weren't long enough for the telescoping column.





For what it's worth, the tilt and tilt/tele columns are pretty much the same from the turn signal switch down. The tele column is just a regular tilt column with the telescoping parts added to the top. That's why they are longer by several inches and this is why I had to make the column so short. The tele column required me to add a couple of square tool bits under the legs of my homemade tool to be long enough, but it still worked ok.

This is how the telescoping lock works. A screw, a push rod and a tilting wedge inside the shaft.