Magnet Car 101--X2 Project
Hi guys, first time here. My New Year's resolution is to quit smoking!
Since I have to do something with my hands (stop laughing now) I'm going to detail some tips & other stuff for "magnet cars".
The most popular H O slotcar is probably the 440 X2. It's been around for decades in the same form & only the places the parts were made in vary.
These cars have now been "outdated" by newer products performance-wise as far as "organized racing" is cocerned. Yes, I know it won the Y2K Nationals, but mostly on reliability. The other cars burned up!!
OK let's see. What makes the cars that race in the Nationals so different??
Supposedly the same parts, only tuning. Yes they use "replacement parts" for some electricals & they change the gearing & tires.
It's already sounding expensive!!
We don't want to spend much, so I'll show different ways to tune a part already on the car. Where it is absolutely necessary to upgrade, I will suggest parts you can use.
I'm not affiliated with nor working for any HO supplier or manufacturer. If you use different parts fine, but I will relate the ones I use.
Let's start with a regular car, if you've several even better. Take the body & rear axle assy. off & rev the motor on track power. Listen for the smoothest spinning motor. Some sound like thrashing machines, others have a high pitched scream. Pick the motor(s) that sound good because it's a good indication of proper balance & it's easier than chaecking resistance(ohms) or static balance.
OK you've found a good sounding motor & hopefully it's is a narrow chassis. Let's work on the pick up shoes first. We'll do the motor tuning during re-assembly later.
Look at the pickup shoes. If they are worn, replace them. Stock pickups (with or without the step) will work fine most of the time. For racing you'll want a silver plated "ski shoe" with a larger contact area. Get as much of the shoe's face to lay onto the rail. Check this by lookng at the car on a piece of track. Adjustmets are made by bending the shoe slightly, usually the front of the shoe hits with the rest of the shoe's face at an angle. Once the shoe lays flat you'll notice a difference in performance. Go further by adding tension to the shoe spring. I use a small tweezer to grip the "tail" of the spring that touches the frt bulkhead. I bend the top of the springs slightly to get more tension. Slightly is the operative word here. You can always add more later. With increased spring tension comes more power & the car aquires a tendency to "pop the slot". To control this we limit the travel (up/down) of the shoe. The cars don't need as much travel when lowered (later). Even with stock fronts there's too much travel. Limit downward travel by bending down the front upper tip of the shoes. Use a small needlenose to grip the shoe at the front, tightly & with a small screwdriver or 2nd needlenose bend down (90 degrees) the top 1/16". With the car on the piece of test track again lift the front wheels off the track. Looking at the pick up tab in front the wheels should just be off the track when the pickups stop. If you have low rails on some sections you may need a bit more travel, but keep it close because this is BIG. Along with downward travel we must have upward travel to compensate for rail imperfections (bad joints). This isn't as critical unless you have no clearance between the bottom of the pick up tab & the shoe. Bend or file the slot on the shoe to get clearance (.005"-.010") just enough that when the shoe rides over a high spot on the rail it won't lift the front wheels. Another place to look on the pickup is where it hangs on the brush tube. With the car on the track there should be just a small amount of "float" at this point. The barrel controls the downward travel & the bulkhead boss the upward. If you have to adjust this make sure it all lines up "flat" when you're done. Adjustment is by bending the "tail" of the pickup SLIGHTLY. Run the car on track between changes to get a feel of what's going on. You should wind up with a "line" along the entire face of the pickup. If you wish to use aftermarket parts be aware that not all "fit" right. Some need to be rebent others are OK. I've had excellent results with Slottech's pickups & double springs & I highly reccomend them. I've had to modify some others!!
If the car is running decent at this time we're ready for the next step. If not make sure you get the pickups right first because nothing else will work to it's best capability without that.
Motor dis-assembly is next. Following the instructions on your "blow-up" schematic (you do have one don't you !) take the car apart. Carefully remove the brush tubes from the bulkhead, try not to lose anything !! Rear bulkhead does not have to be removed as long as the pinion is still good & there's no trash (hair/lint) on the arm shaft.
If you remove the pinion replace it with a new one or Loctite (red) one into place.
Brush tubes tend to slide around in their mounting holes so let's fix that with an X-acto knife. Hold the brush tube with a pin vise or similar & "score" the tip that fits into the plastic. 3-4 good scratches will keep the barrel in place. If you wish to upgrade to "tapped" brush barrels now is the time. The set screw allows removal of spring & brush without further dis-assembly & allows you to fine-tune performance by changing springs and/or brushes quickly. Also the set screw allows you to change tension & compensate for brush wear. Either way I suggest new springs- .006" & Silver brushes. If cost is a problem, stretch the stock springs slightly but they'll be hard to get back in place!! Silver brushes are lower in friction & wear quickly but make a big difference in response to throttle. Put the motor back together using spacers to "center" the arm in the magnetic field. The motor will have a tendency to move front or back in the mags if not properly spaced. Usually the stock spacing is close. Make sure the motor is not binding or hitting magnets or front bulkhead. With new brushes in place check for RPM. If using other than silver brushes break them in on low power for 4-5 minutes. I use the 6 volt battery for my track & just let the motor run (oil it first!) with no axle. If you use set screw brush barrels you can fine tune after break-in by turning the screw in or out SLIGHTLY.
With the motor running properly now let's do gears. The stock pinion will do if it's not slipping. If it slips even a little, replace it or Loctite it.
Crown gears tend to chip or bend teeth. If only one tooth is bent it's still slowng you down!!
Replace it with an aftermarket gear or the LifeLike unit. The stock gear ratio is great for home tracks (short straights lots of turns) If you change ratios keep in mind where you'll be racing. If the straightaways are longer than 10', try a 23 tooth crown. If longer than 14' try a 22 tooth gear. Gear spacing is difficult on an X2 because the rear of the car has nothing to prevent it from flexing. I prefer to set my spacing between the wheels & chassis so that the tighter fit will keep the rear together better. In other words put the spacers behind the wheel. With proper spacing & a gear boss the mesh will be smoother. Start on the gear side. Put a couple of spacers (plastic) on the axle before mounting the wheel. Move the wheel inboard (easier if you have a wheel press) until it just touches the chassis. We're looking for the tire/spacers to prevent the crown from "choking" the pinion. As the car goes around a turn the tire has a tendency to push the axle in the opposite direction. In high speed turns (or banked) this can bind the motor in the turn. Set your axle spacing so that the pinion can still move fore/aft without binding on the crown at it's most inboard position. If the pinion has a nipple use a gear boss to help keep it all together. On the other side of the axle repeat the spacers as needed & mount the tire as close as possible to the chassis without binding. You should wind up with .005"-.010" total movement side to side. This may seem close to some but only if you let hair or lint get in there.
Now the tires. I prefer to use silicone coated sponge tires for racing. For my home track I use slip-on silicone tires. These come from many manufacturers & most will slip-on to a 440 X2 wheel. I suggest using rims with dual retaining sides. If cost is important stick with the stock rims as long as they're true. I've found many aftermarket rims out of round. Twinn-K (AJ's) makes the better ones, new ones are around too. Tire size will be a major point & that can also get expensive. While you may need to get the car perfect for a National race, close will work for home tracks with power packs. BSRT makes an excellent tire in several sizes & 2 compounds. For most tracks you'll want to start with a .420-.425" in a slip-on (harder tire) or .435"-.440" when using a sponge-based tire. Braking distance & feel as well as handling & response are all affected by tire size in a magnet car. It's better to be slightly high than low too because if the car's dragging on the track you'll get mixed signals for over & under steer & the car will be slower. When it's right you'll just be skimming the high spots on the rails with the traction magnets. This can be confirmed by using a magic marker to paint the bottom surface of the car to see if it's touching & where on the car it's touching. Again remember you're looking for a trace of contact only !! This adjustment is critical & can only b learned through experience, trial & error. But this will get you close, I hope!!!
By now your lap times should have dropped considerably or we've gone wrong someplace! The front end on the X2 is not as critical because the motor magnets are already too far off the track to help with downforce, so it's main job is to hold the car up off the track. Sure getting it lower will help handling but not through magnetism. Most aftermarket front end sets are very good & will work well. Don't lower the front so much it drags though. The best set-up is with independent wheels & custom sized tires. I suggest .355"-.360" as a starting point. If you want to stay with the "stock" front make sure the wheels/tires are round!! O ring set-ups are also available but these don't allow height adj. & if you're going to all this trouble you might as well do it right.
Next should be a Lexan body (actually the single biggest change in performance so far)
but this is turning into a book!!
Let me know if this helps anyone. I'll check back & see if you want more!!
Excellent article on setting up the X2. It doesn't seem like too many people are looking at this board. You might want to jazz it up with a couple of photos and submit it to SlotCarBob for the HO World webzine. ...Tom
Re: X2 tips
Hi Magnuts,
Long time ago we met & I'm sure you've forgotten-1978 Nats in BuenaPark. Great to hear from u!!
Not worried about audience. Just trying to quit smoking & this keeps me busy for whie at a time. Thanks for the comment 'cause it makes it worth while to write.
Re: X2 tips
Hi guys,
Boy, this does read like a book. Looong! Hope I haven't bored ya!
Anyway I was just putting laps on a car & I had a problem with the guide pin. I hadn't touched on it before 'cause it was just too obvious & I missed it. Mine turned out to be bent. Backwards! The car de-slotted & hit a track joint. I didn't catch it at first but I noticed the car snapped around instead of sliding through the turn. So new pin is setting in Black Max now! Yes I prefer to glue it in, but even if you don't,keep an eye on it & make sure it's straight.
Hey, let's mount a Lexan body on this 440-X2!!
If you're going to do this it's worth doing it in a way which will let you swap bodies around. I use a template made out of scrap .040" Lexan (2"x1/2") A strip long enough to reach both axles. I mark the spots (axles) & drill 2 x 1/16" holes. With 2 blank axles holding the template in place, I pick where I want the holes for the body tubes. On an X2 I prefer the front hole just under the brush tube, remember to allow for clearance for the springs!! I like the mounts here because a longer body pin will fit all the way in. The second (rear) hole should be .500" away so that you can use a staple to mount the body. I make this hole higher to get the right distance & also lets the stiffness of the body keep the pin in place. All 4 holes in the template can be 1/16" if that's all you've got. The bodies should still swap around & you can bend the tips of the staples slightly to compensate for small differences between cars.
Using a template & 2 blank axles you can drill holes into the sides all the way through the plastic. I suggest you do it with the car apart & use a sharp bit in a pin vise. Make sure the holes are straight in & don't hurt yourself!!
Use 1/16" tubing (K&S usually has a display in Hobby Shops) I like alum over brass, easier to cut & lighter. Cut 2 pieces .300" long & 2 x .275". Longer will go in front. Use an X-acto on the tubing & just roll it on a flat surface. The scribe mark is usually enough with aluminum tube & will come apart easily when bent. Deburr one of the ends of the larger piece you're cutting from & then each time you cut a piece off it will already have one end deburred & ready to be pressed into the chassis. The tubes can be pushed into the chassis using a "push pin". I use an old Krazy Glue green pin which I've ground the sharp tip off. It's best to glue the tubes in place for serious racing & to keep the front tubes from slipping in case of accidents.
Once the tubes are in place you'll want to check width to fit inside the bodies & for "legal clearance" (1.3125" max ). If you keep it under 1.25" at the tubes you'll probably be able to use most bodies.
When you start out with Lexan bodies it can be difficult to see where to mount the pins or staples. Leave a strip on the sides unpainted so you can see exactly where the holes go.
To mount the body on the car make sure it has clearance around all four wheels. I use an axle with oversize tires & then just let the body sit on the tires. After the holes are made fit a pin in place & check clearance with your real tires. Allow room for body float around the tires. Use tape to reinforce the body where the pins go in. Also use tape to hold the pins or staples onto the body so they don't get lost during a crash. Well, by now the car is definitely different from Showroom Stock & lap times should reflect it. Keep the track & tires clean & have fun!!
Re: Magnet Car 101
Geeserotti...I'm amazed you can remember me from the 78 Nats, at my advanced age, memories that far back are hard to come by. But still, maybe if we knocked wheels again, it would come back to me!
Best Racing,
Tom
1 point
the Motor magnets d make a difference in handing.
I have played with this using a gauss meter, magnet film, and test driving.
I have found that most motor magnets have one side stronger than the other. So I find out if the top or bottom is stonger, and place the strong side down. Better lap times.
I than search for magnets that are balanced in the motor field, and have the strongest top/bottom gauss reading. Much better lap times.
Re: 1 point
Hi Slotking
I was checking out your gaused magnets while your car was flying off the track at the ECC!!
Remember me? The guy with 1/2 Cheetah!!
Yes the better the mags the better the performance, but my point here was just to make a "fun & drivable" car out of all those MGNET cars sitting in people's boxes that never get used, I don't need no stinkin' gauss meter!!
Magnuts
Of course I remember you from '78 you "were" THE MAN when it came to magnet traction, when I first read about your stuff in Car Model. You had a v nice layout pictured in the mag. Were you in the Dakotas at the time?
Anyway, great to see you are still involved. Race any unlimiteds lately??
Current doings...
No unlimiteds for me! I can barely keep up with a Restricted Open car any more, especially on a Buck track! Currently, been concentrating on Fray Tjets...I met Howard Kilgore at the Fray. He just returned to me the brp Mk. II magnet car driven by Randy Kemp in the 72 Indiana vs Michigan race, and featured in Howard's Car Model column in April 1973. You can see it at horacer.homepage.com/magnuts.html. I'm planning on doing an article on this car for HO World.
Best Racing,
Tom
Re: Current doings...
Yessir!!
Magnuts That's the car I saw & the mag. Sure brings back memories!!
I too can no longer "see" the unlimiteds, too fast. But I stll love the speed!!
I like t-jets for their visibiity & correctability-you can catch a slide & keep it giong for the time it takes a Cheetah to turn 1 lap!
On the minus side, I find the electrical system a pain in the b***(usually run a magnet car first to clean the rails) & performance from car to car is inconsistent. I like to run 'em with hardbodies & brass pan. Got a couple with the old TCP front wheels/Faller springs set-up & AF/X gear plate grafted into place, relocated the rear axle slightly upward & using Wiz 20t crown-Hauls donkey, but I'm sure it's not legal anywhere!
BTW don't mean to be impolite, just careful. I didn't race with you at the '78 race, I was in the Amateur half of the program, so I'm not sure if you recomember me. Joe D
More current doings...
Joe D ...The current racing scene certainly has some great competitive drivers at all levels of the sport, but what frustrates me is the closed nature of the rules related to the different classes. There just isn't much room for builders to get creative in any classes that I'm currently competing in. The Fray style Tjets, have only the tire and wheels that can be freely changed. That prompted me to create hubcaps to fit in the Wizzard/ThunderRubber tires.But even though the regional organizations I run with (UPHORA, MACT, CRL, and VHORS) don't allow anything but off the shelf parts, my local club beachracers.homepage.comhas several classes where builders can use there imaginations... This shows a Super II Tjet with Radio Shack Rare Earth magnet dots compared to a Fray Tjet. We also have a class for non-magnetic unlimited Tjets, which I have a "Carl Dreher" handling pan equipped car. It's fun to use the techniques we used back in the day, combined with some of the better parts currently available (mostly tires, comes to mind)...
Still playing with cars...
Tom Bowman
Re: More current doings...
Magnuts
Great Stuff!!
Racing begs for imrovements & innovation. Rules stifle new ideas but create a more level playing field, so they say!
Yes the current classes being raced are very restrictive, all except unlimited which allows more leeway for the imagination. But unlimiteds are priced way above what the club or home racer wants to spend. There should be a class for ceramic magnet unlimited cars to allow "chopping" & more.
Imagine if your club rules mandated a specific car back in the days you were experimenting with that Bachman!!
Progress indeed!
JD
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