In Slot Car Tech News

We all know there are lots of not-so-well designed slot cars on the market. I’m not talking about the common gripes, such as knurled axles and press-on plastic wheels, too-delicate wings and mirrors, or guide flags too long, thick, or deep to fit the slots on some brands of track. Those can be aggravating, certainly, but what I mean here is cars that have chassis, and sometimes bodies, so ineptly designed that no amount of aftermarket parts or routine tuning will ever make them run or handle right (and in some cases, look right). These cars need a complete redesign. Probably every reader of this article who has been in the slot car hobby for a while has his list of nominees for a complete makeover.

Not too long ago we heard from a customer who decided to take the car at the top of his hopeless design list and rebuild it the way he believes it should have been made to begin with. What’s interesting about his project is that he didn’t go the usual route of mounting the body on a Slot It HRS chassis or replacing every moving part on the car with NSR components. Instead, he used production replacement parts from cars of various manufacturers, along with most of the original chassis, to create a car that performs a whole world better than it did originally but could have been produced in volume and sold at a normal retail price. In other words, his redesign could have been the original design and would have performed much better. He wishes to remain anonymous in order to avoid the possible wrath of the manufacturer, so we won’t tell you his name but we’re going to let him tell the story… “Have you ever taken a good look at a Ninco Cobra? The body is beautiful. They did a great job on it, not only in modeling the overall shape but also in capturing all the details from the raked-back windshield and the roll bar to the side pipes and the jack brackets. But then they stuck it on top of a chassis and running gear that somebody should have been fired for. Of course, that was quite a few years ago, and the state of the art then wasn’t what it is now, but even then they could have done a lot better.

For starters, that big lump of an NC2 motor, sitting approximately amidships, weighs too much, takes up way too much space, and doesn’t leave any proper location for a traction magnet. Of course, if you’re a rabid non-magnet zealot that won’t matter to you, but a truly well designed chassis provides the option of racing with or without magnets. Many non-magnet racers refit these cars with NC-1 motors to get the power down closer to what the chassis can handle.

Then there are the wheels and tires, which are grossly oversize. The wheel diameter is a scale 18.56 inches, which is about what you’d find on a present-day tuner car, not a 60s sports car. The tires, however, have a typical 60s profile, which means the chassis sits ridiculously high off the track on what looks like truck tires. Finally, they put a too-deep interior tray into the body. That meant they had to jack up the body to clear the motor, leaving a big gap between the tires and the fenders.

The result is a car that looks like a cartoon of a Cobra or, perhaps, a Cobra set up for offroad racing, but definitely not a proper 427 Cobra race car. It’s also a car that essentially can’t get out of its own way on the track. It’s like a committee hashed out the packaging of the car’s various parts on a Monday morning.

Still, that body really is nice, which set me to thinking. What if Ninco were to redesign the chassis, fixing all the mistakes, and re-release the car? Since I had just acquired two Ninco Cobras I decided to explore the idea. I set a goal of making the Cobra into a car that could be both legal and competitive in my GT-1 class for 1960s and 70s SCCA production cars and sedans. This class includes Scalextric TransAm cars and L88 Corvettes. It also allows kitbashes using the chassis and mechanicals from these cars. The only non-stock part allowed in this class is a pair of Indy Grips 1009 rear tires. If I could make the Cobra competitive in this class it would mean a huge performance improvement over the original design. Making it legal for the class would ensure that it would be a design that could be mass-produced and sold at a reasonable price.

My first idea was simply to transplant a shortened and trimmed Scalextric Mustang chassis into the Cobra body. The Mustang’s front and rear axle assemblies are the perfect width to fit under the Cobra’s fenders, and the wheels, at a scale diameter of 15.68 inches, are much closer to the proper diameter.

Size comparison between Scalextric TransAm car wheels/tires and stock Ninco Cobra wheels/tires.

However, it soon became clear that this wouldn’t work, because the Mustang’s guide sat too far forward to clear the Cobra body’s short nose. The same proved true of all the other possible replacement chassis I tried, including the front-motor setup from the L88 Corvette.

My next idea was to install the complete Scalextric sidewinder setup in the Cobra’s original chassis. The problem here was to install all the necessary motor and axle mounts and then make them solid enough to withstand the hard knocks of racing. Scrounging through my parts bins I found the perfect solution in the form of a Fly sidewinder rear pod. This part goes by several different stock numbers, including B34, B104, and B108. They are all the same except for the color plastic they are molded in. The Scalextric motor and rear axle assembly fits perfectly, delivering a smooth gear mesh with the stock Scalextric sidewinder gears.

Before installing the pod I had to grind off the original Ninco motor and rear axle mounts, along with some additional material from the chassis, using my Dremel Moto-tool with various cutting bits. Because the chassis curves upward aft of the rear axle I had to contour the bottom of the trailing edge of the pod to match. For this I used my bench-mounted belt sander, but it could also be done with a Dremel or even a file. Emery boards came in handy for cleaning up edges. I also cut off the triangular extension from the front of the pod that includes a mounting tab for Fly chassis and a housing for a Fly disc magnet. Since the pod was going to be glued in the tab wasn’t needed. Also, I was going to use a Scalextric bar magnet just forward of the motor so the disc magnet housing was in the way and needed to go.

Once I had the pod and chassis shaped for a good, close fit I applied CA glue to the bottom of the pod and positioned it in the chassis, clamping it in place until the glue set. I also wanted to get rid of all the up-and-down slop in the front axle installation, so I cut a piece of 5/32″ brass tubing and epoxied it into the chassis. The tube also serves as a reinforcement for the guide mounting.

The next step was to snap in the motor and install the axle assemblies. A visual check showed that the bottom of the chassis now rode at a much more reasonable height above the track. However, when I test-fitted the Scalextric magnet in just forward of the pod I could see that all the material I had cut away to fit the pod in place had compromised the structural integrity of the chassis. The magnet literally pulled the center of the chassis down to the track. Clearly, some reinforcing was in order. I cut some small pieces of Evergreen strip styrene and assembled them into two L-shaped structures that could be glued to the outer portions of the chassis and to the ends of the pod to restore the lost strength. (See photo.) Of course, a chassis molded in one piece with the pod as an integral part of it wouldn’t need this.

I retained the Ninco guide and lead wires. In soldering the lead wires to the motor I deleted the little capacitor Scalextric always ads to prevent interference with TV signals. This component is largely redundant in the US since almost everybody has cable.

In order to mount the body the interior tray had to come out and with it came the windshield, roll bar, and gas cap. The body posts needed to be shortened to get the body snuggled down over the wheels and tires where it belongs. The rear ones only needed to have about 1/16″ taken off, while the front ones had to lose about 1/8″. I also had to trim about 1/16″ off the top edge of the vertical panel at the front of the chassis that carries the radiator screen detail. I actually cut too much off the posts, which is why you see washers glued to the chassis in the photos.

With the body now sitting properly on the chassis the interior tray no longer fit over the motor. I cut out just enough of it to clear the motor and pod and used Evergreen sheet styrene to make a boxlike structure to fill in the opening, as shown in the photos.

I painted the new portion of the tray black to match the rest of the interior. I could no longer use the original driver figure, so I scrounged through my parts boxes for a lower-profile driver that would fit on top of the modified interior tray and still not stick up above the roll bar. I finally used the arms and shoulders of one figure and the head of another to make a driver that not only fit the space but also looked period correct.

I also made two other modifications that weren’t essential but enhanced the car’s appearance and functionality. I cut the windshield down to less than half its original height, as was common practice on SCCA production sports cars back in the 60s. This gives the car a more authentic race car look and also makes the windshield much less vulnerable in crashes. I also replaced the roll bar with a new one made of a Plastruct product that consists of 1/16″ diameter styrene tubing with steel wire inside it. The new roll bar is bulletproof and looks a little heftier than the original, which I thought looked a bit on the spindly side of scale.

On the track the rebuilt Cobra is much faster and better handling than before, even without the magnet. With the magnet and the Indy Grips it’s fully competitive in my GT1 class and a lot of fun to race, the magnet increasing its limits without sticking it down so much it becomes boring to drive. It actually drives very much like a non-magnet car with very high cornering limits.

Best of all, the car looks like a 427 Cobra should – low, wide, and aggressive with the wheels tucked up into the fenders and the revised windshield and roll bar providing just the right competition car touches.

There is nothing I’ve done to the car that Ninco couldn’t incorporate into a revised version of the car for sale today. In fact, what I’ve really done is rebuild the car the way Scalextric would have done it. In the process, I’ve given it the same excellent out-of-the-box driving qualities that make Scalextric cars so good for giving new hobbyists the best possible experience with the hobby and brought it up to a level of performance fit for a model of one of the fiercest production sports cars ever raced. Perhaps it’s time for all the slot car manufacturers to take another look at their earlier creations and see if they could be reissued in new and improved versions.”

Well, that’s our customer’s story. Your opinions may vary. If you want to do this project yourself we have the cars and all the parts you need right here at Electric Dreams. And, of course, this article will probably give you new ideas of your own. That’s one of the things that make this hobby so much fun.

If you have any questions or comments on this article please leave them below.

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  • knight4444

    You were very clever but I would have just filed down the body post and maybe put on slightly lower profile tires to get a lower look. I’m going to try to convert mine into a AW setup. Thank you for posting your successful project.

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