Liberating a Shelf Queen in Bondage

The retail life cycle of some slot cars is very short, and unfortunately, many of the most attractive of Fly's Classic Le Mans slot cars have been discontinued. While some are still available through eBay and a few online vendors, the price has escalated tremendously, in some cases, quadruple the original price. I've even observed a vendor's prices marked up 30% immediately following my purchases-- talk about market-driven! We're not talking about true "vintage" here-- many are only a few years or even months old. Yes, some slot cars were good investments... if you selected wisely and were disciplined enough to keep them unused and mint in box, or very lightly used.

For folks like me, that's a hard thing to do... no, it's probably an impossible thing to do. I see these as pretty cars that I want to tweak and play with. When I buy a slot car, the looks or the history do the selling, but once it's in my paws, I have to know about the performance, and add my own personal fingerprint. Otherwise, I'd collect die-cast cars (and there are some nice ones!). I want to know that the beauty is more than skin deep-- it has to run, and ideally, it should run well. If it doesn't, I'll try to fix it. If the car's an unredeemable dog underneath, it loses some of its eye-candy luster (Can you say "Auto Art Countach"?). I can't lie to myself-- if a car requires magnetic implants to run acceptably, I'll always be aware of that, no matter how good she looks.

The Porsche 917K 1970 Le Mans Winner is a beauty that I wanted to see racing around my track, so this is about turning it into a usable slot car: Liberating it from a future of shelf-queen bondage and eventual resale on eBay. As they say, "a fool and his money are easily parted"... and it takes a special kind of fool to deliberately devalue a "valuable collectible". That vaunted title seemingly raises the stakes, which can only make the job more interesting... but it's an illusion. The reality is, when you spend big bucks on stuff like this, you're not buying unique, stellar performance or exemplary craftsmanship-- you're buying through the distortion of supply and demand. It's actually a fairly low-risk endeavor since under the skin, all Fly Classic Porsche 917Ks are virtually identical. As long as you don't lay a soldering pencil on the body, you can pretty much swap out any part from another Fly 917K and continue merrily along.

BASIC TUNING Yeppers, it's a downright purdy car, but how does she run? It's well-known that out-of-the-box, Fly's Classic cars usually perform poorly, and this was no exception. Besides the poor electrical contact, the strong magnet contributed to its lurching, constipated performance. The main culprit is usually the guide braid, which needs to be spread out and curled to make contact with the track. There are a number of other things that you may observe on its maiden voyage-- poor handling, bumpy ride, deslotting, sluggish and uneven acceleration, strange sounds... All those things can be fixed by doing the tuning tasks that are graphically demonstrated in Harry Wise's excellent article at Home Racing World. After pulling the magnet, I followed his steps for motor shaft trimming, pinion tapering, rear axle shimming, and wheel and tire truing.

When you separate the chassis and body (causing at least 100 hit points of instant devaluation), watch for any parts to drop out. The Porsche 917s have a very small mesh grille in the front that's not glued in, which would be easy to miss or lose if you didn't know it was there. It's a good idea to remove those kinds of parts and store them before instead of noticing that they're gone later. One word, in case you forget the second time: Glue.

Since this will be a lighted car, I've replaced the front stub axles with a single brass tube. This isn't always necessary, but removes a variable because it eliminates the slop and keeps the tires from rubbing against anything in the wheel well. Unfortunately, it also eliminates the beneficial effects of wheel slop, which can reduce the likelihood of deslotting on a skewed section of track (discussed in this article). Although this problem can often be fixed by adding a shim between the guide and the body, I had a frustrating time making one the right length that allowed the front wheels to turn and made the millimeter's bit of difference between staying in the groove and deslotting. Although I hate to give in, it was just much easier to replace the guide with Slot.It's wooden track guide, and trim the depth and length (a duct tape extension really does look cheesy).

Since this is supposed to be a special car, I swapped out the motor with a similar Slot.It 25K motor I had lying around. I honestly can't tell if there's any performance difference, but having spent extra money on it makes me wanna believe it's so. I used the original wires since Slot.It's silicone wires are thicker-- this makes a difference when you try to close up the chassis and body. Since I was going to be adding junk inside, the fewer frustrations, the better.

The one concession that I've made to this car's collectible status is replacing the tires with generic Fly B-46 tires. I like the cool "Goodyear" lettering and thin blue stripe, but know that there's no way those will survive the wear of usage. I don't know if this is a rational thing to do, since I may never put them back on the car. They'll probably become hard and unusable stored in a baggie. But I don't have any way of repairing or redoing the lettering, so storing them lets me avoid the feeling of loss when they inevitably get worn off from usage. Actually, I replaced the entire rear axle assembly, since the replacement came with brass bushings (versus the plastic ones). I removed a wheel and added some shims to keep the tires from rubbing against the chassis.

SPECIAL MODIFICATIONS In preparation for modifying this car, I tested most of these ideas in a "not-yet-rare-collectible" Ferrari 512S. The lighting circuit in/out switch seemed worthwhile, so I wanted to put one in here-- but didn't consider the fact that the 512S and 917K are two different models, with different constructions. So I winged it, cutting a hole in the cockpit side to give the switch some clearance, and slicing off a bit of the chassis stiffening rail. You can't see the switch and wires when the car's assembled, but I was prepared to convert the cut-out plastic into a cover. The passenger's seat area was also grinded to create a groove to give the motor wiring a little more clearance. This really wasn't necessary since the 917K's cockpit seems to give a little more clearance with the chassis, but it doesn't hurt either.

Since I had the whole thing apart (and since it was a speshul car), I decided to tackle a few minor details, like giving the driver some eyeballs. The unpainted skeletal face is kinda creepy. If only his arms were articulated, he could actually pretend that he was grasping the steering wheel.

I also decided to work on the intake fan platform, cutting out slices under the fan (which in theory, should improve motor cooling), and giving the fan a detailing wash. (Normally, I just dust the fans to weather them, but as I've said, this car is speshul...)

To better match the pictures of the actual car, I painted the fan platform red... and discovered that the car is a really, really difficult shade of red to match! I tried 3 different reds, adding orange, yellow and white in various combinations, with gloss and semi-gloss, by brush and airbrush... It always dried darker than I'd estimated, so I never achieved a good match. Grrrrr. I may try again later, but for now, "Uncle!"

I've covered the LED installation before, so I won't bore you with it here. This picture shows what the ugly trimmed and tinted LEDs look like before everything's assembled ('cept the lenses-- don't forget the lenses like I did when I took this picture).

From doing this a few times, I've learned that you can get those stubborn lamp lenses off fairly easily after you drill the pilot hole through the back: Poke through with a pin. This lets you enlarge the hole from the inside of the reflector, leaving a far cleaner edge on the foil. It also makes it easier to blow drill dust out of the lamp, and is less likely to cause damage to the lens (other than the pin point).

Don't glue the LEDs in place until after you've installed the lenses in the lamps. There's not much room inside the lamps, and if the LEDs are mounted too far forward, the lenses won't fit back on.

Ideally, the lights should be balanced in tint, intensity and alignment, but it's easier said than done. Even though I tested the lights as they were being tinted, little variations became apparent once they were in the reflectors with the magnifying headlamp lenses. In some cases, the reflectors/lenses imparted a strange pinkish hue when viewed from a particular angle, reminiscent of an effect I'd seen in ENX projector bulbs (if you're familiar with that...). The depth that the LED is inserted into the reflector and variations in the reflector foil play a big part in how the lights look. The sides of the LEDs should also be tinted if the LED protrudes into the headlamp, and hopefully, the tinting won't be scraped when the LED is inserted. The bottom line is that you really can't tell until you've put it all together, at which point, it's a hassle to disassemble to fix by trial-and-error. I'm still not ready to concede to an amber LED...

Last look before it's screwed shut! I could have used my last Ninco circuit on this (which is actually a better circuit), but I'm still excited about the home-made lights; besides, this gave me the opportunity to figure out how to do it in a 917K body. There's maybe a little more room inside the 917K body than the 512S, so everything fit without much trouble. This time, the circuitry is more of a unit, and all the components are soldered together in a "U" shape so it can be lifted out. It's not glued to the body (the lights aren't glued to the body either) but is held in place and cushioned from rattling around by the negative lead which also runs along the side. This modular approach made it much easier to work on since I didn't have to risk burning holes in the body.

I used different resistor values for the upper and lower headlights; 10 ohms for the upper ones, and 160 ohms for the lower ones (actually, doesn't make much difference). This time, each of the rear SMT LEDs got their own 2.2K resistor.

Amazingly, it screwed shut without difficulty and even passed the 9-volt battery test... Vroooom, vrooom!




PERFORMANCE It took a number of laps to break the car in (probably around 150 total, including the initial out-of-the-box trials), but as it ran more and more smoothly, the laptimes got better and better. 193 scale MPH is not too shabby for no mags with stock Fly tires!

Many people hate 'em, but I like Fly's tires. After they undergo a few initial sandpaper truing sessions alternating with a mysterious chemical treatment, I get decent, low-maintenance performance on my seldom-cleaned, texture-painted Carrera track. This tuning doesn't work for all tires though-- The crumbly Spirit tires were sanded down to slicks and they still wouldn't hook up! I've also looked elsewhere for ultimate performance: Ortmanns gave only a few 1/10s of a second improvement in laptime, but gave some of it up as they got dirty. I don't like the idea of putting white polyurethane tire dust on my track, so I stick with the good old-fashioned synthetic rubber.

During the trials there were a few understeer deslots, and I flipped her once-- thankfully, with no scuffs. Hey, I could wipe off the gold headlight dust, give her a virgin chassis, replace a few body parts, shackle her in the display case, and sell her on eBay! --05/16/06