X-Traction from Auto World
What does it take to settle down and improve the X-Traction from Auto World? Here is my process to improve the stock chassis.
Initial view of the chassis:
Initial observation of the chassis:
Gear mesh was tight
Axles and hubs appear to be straight
Left rear tire shows minor grooving as though the body that was mounted was to
close to that tire
Pickup shoes show wear to the nose rather than down the length indicating they
are needing adjustment.
Initial runs at Marion County Raceway turned avg. lap of 4.175 with best lap of
4.033
I found grease that had hardened under the center
idler gear from the original AW assembly. I recommend always removing all that
grease first thing when getting on of these cars. Grease is not the ideal lube
for a slot car.
The front motor brush support, the metal arm underneath the chassis, was bent up
putting undue pressure on the front brush. I removed the motor brushes and
springs and gently bent the arm to a level position. I then cleaned the armature
comm with rubbing alcohol and cleaned the motor brushes by wiping on a piece of
white index card ( the texture in the paper works great for this purpose).
I also used an old ball point pen that had ran out of ink. It is a fat tip pen and I carefully burnish the edges of each section of the comm where the brushes travel. Just enough to give it a slight rounding instead of the abrupt metal face. Since I have the chassis apart, I take this opportunity to oil motor shaft where it meets with the top plate. I oil from both below and above lightly. With the armature out a needle oiler makes this simple. I also oil the rear gear on the plate from both above and below. Again, lightly. I oil all 4 points where the front and rear axles meet the chassis. And finally with the armature still out of the chassis, I run the needle oiler shaft directly up where the bottom shaft of the armature will rest.
BTW, this is one of the best AW chassis I have
seen. Nice and smooth on reassembly. I think I forgot to mention to oil the
center shaft on the armature plate where the idler gear is located.
Re-assembled and onto the track. What a difference! Right out of the gate I was
able to run a 3.71 lap with a 3.87 avg.
The car is smooth and has considerable more horsepower. Getting ahead of myself,
I couldn't wait and put some Super Tire rear slip on silicones on the back and
was able to turn a fast lap of 3.471.
Next is to limit the travel on the front pickups and then the car is done!!
Note the large window area on the pickup shoe. We need to limit this area to keep the pickup shoe springs from pushing the car out of the slot. But we need to have enough travel to not rob power from the motor during normal pickup travel. There are a number of ways to restrict travel, i.e. bending the top of the shoe over, heat shrink tubing, rubber band collars, and simple masking tape. For this car, I will use simple patches of masking tape to limit the shoe travel.
I cut simple squares of masking tape and stick to the front of the pickup shoe with chassis resting on a test block or a piece of track. Stick to the front of the shoe and test by lifting the chassis and viewing the shoe travel. I like to see about 1/16" travel. When you are happy with the position, take a pair of needle nose pliers and press the tape to the shoe to fix the location. I then apply a second piece to the back of the shoe top and press the again. Repeat for the other shoe and confirm that both shoes have equal travel.
Finally, back to the track. And this car is FAST!! With stock front and rear tires the car turned a fast lap of 3.578 with an average for 10 laps of 3.665. A full 1/2 second per lap improvement!! Now back with the super tires on the rear and #5 O rings on the front. Car turned a 3.203 with a 10 lap average of 3.297!!