Problem solving is an art and also a major part of being a hobbyist. This topic was chosen as a simple exercise in the performance of the art. Didn't I do this article before? I did an article on gluing in a motor, but this is an update to that article and also the review of the SCX CART VISTEON LOLA. The problem being addressed here is that of installing a smaller than stock motor in an oversized engine bay.
All Electronics sells a cheap but effective motor that works in slot cars for $1.00 each or 10 for $9.00, which works out to $.90 each. They are Mabuchi FF-130SH motors and they were reviewed a while back. Physically it is the same size as the Falcon class motors. The reason this motor was chosen is that it produced good results in the past and I had it in stock and besides a Falcon 3 was not in the parts bin. If this works well then it will be replaced with a Falcon.
Why change the motor? For several reasons. The first is that SCX motors stink and this includes the Turbo motors. Another reason is that the clearance is close between the motor and the body. I tried putting in the SlotIt SCX upgrade, but there were clearance issues with my car. Others have been successful, but I was not even after grinding away part of the bodywork. The motor would fit but the engine pod would not float freely like it was designed to do.
Motor and Chassis Prep
Simply stated the motor and chassis must be clean. This step is essential as it guarantees the glue will stick to the plastic and to the motor. I clean all labels off motors that are to be glued in place. A single edge razor blade does the trick. The old glue from the label is then removed as well. Wal-Mart sells a product called Goo Gone that is one of those non-toxic Citrus based cleaners that takes off glue, oil lipstick, etc. I clean the motor and the chassis with it. To insure that it is clean I have been known to clean it a second time with denatured alcohol.
Attaching the Lead Wires
Please refer to my earlier article for a discussion of the problem and a solution. The results should look something like the following picture.
Motor Alignment
Press the pinion on the new motor so that the same amount of armature shaft protrudes as on the original SCX motor. Put the engine in the engine pod. Notice that the vertical alignment is the same as with the original motor, but when the gears mesh they do so almost perfectly. The motor is shorter and narrower than the SCX and so it slides around on the horizontal plane. Take the motor out and put one small drop of CA glue on the bottom and put the motor back in exactly where you want it. The CA glue is used to temporarily hold the motor in place and should not be used for the main glue as it is hard to remove and may have a negative effect on the plastic with the passing of time.
Gluing in the Motor
When the CA glue is dried, which should be in less than thirty seconds, get out the hot glue gun. Don't have one? Mine came from the dollar store for a dollar and it works fine. Plug in the gun and make sure it heats up completely. Begin by running a bead of glue down each side of the motor, and then along the back and across the front. A picture will explain this better than words.
Note in the following picture that a small bead of glue is placed in the gap at the back. Be sure not to get glue on the armature or bearing.
If the motor does not stick then you did not have the surface clean.
INITIAL CONCLUSION
The motor is in place, the engine pod floats freely, and so the car is ready for testing. The car ran for over a thousand laps on my tiny 7.5' test track and never came loose. Tomorrow the car will be tested on the 118' track at the commercial raceway . I will report back and give a progress report with a bug fix.
Removing the Motor
Assume for a moment you want to remove the motor because it died or you just want to try something new. How do you do it? Take a pair of needle nose pliers and grab the edge of the glue and pull hard. It will peal off. Next, because there is a drop of CA glue holding the motor in place, twist the motor on the horizontal plane and it should pop off. Do not lift the motor to break the glue. Once the motor is removed scrape the remainder of the CA glue off the plastic and also off the motor if the motor is still good. Put the new motor in using the preceding procedures.
RESULTS
What do you want me to say except that the car is faster. The real time test will be when I get the latest Falcon in it. The motor did not come loose. The car went smoothly through the turns. The motor is better suited to a lighter car, but was faster than a SCX at 15 volts/10amps. I am going down a tooth on the pinion as it did not run out of steam, but was a little sluggish off the slow corner before the straight.
MATERIALS LIST: * = Essential
*Hot Glue Gun
Single Edge Razor Blade
*New Motor (Including pinion and leads)
*Soldering Iron (Including solder and flux)
*CA Glue (Super glue)
Goo Gone/Denatured Alcohol
Pliers (For removing the hot glue)
Screwdriver (For removing the body)
FALCON/RIPPER UPGRADE (6-11-05)
I made the upgrade to a ripper because the FF-130SH, although faster than an SCX, didn't seem like it was overpowering the chassis. The car acted like it was asking for more power. Now in non-magnet cars this is a delicate operation as you can't just add a tweaker magnet to solve a minor problem. I had two motors on my motor shop, a Falcon III and the Little Ripper. It turned out an easy choice to make but still a problematic one. Both motors had too short of a shaft to hold the axle in place, but were long enough to let the gear mesh. The solution was to shim the axle with copper tubing to hold it in place.
Which motor did I chose? The Ripper as it had a longer shaft. The permanent Loctite, which is not permanent, was used to attach the pinion as this is a 30K+ motor. The ratio chosen was an 8/27 as I wanted more low end response and still a reasonable top end. I got both. Later I will try an 8/28 but that is another story.
Making the Shim: When the motor shaft is not long enough to engage the part of the gear that keeps the gear from moving back and forth the axle has to be shimmed with some type of spacer. These can be made from plastic or brass tubing. I prefer plastic tubing as it is easier to work with. Basically you cut a piece of tubing that runs to the suspension carrier or to the bearing. What this does is keeps the axle from floating back and forth. When you cut the tubing you should cut it a little proud (proud = too long). The tube is then filed to a perfect fit. The plastic also has another advantage. Since the type I use as the spacer is about the same out diameter as the part of the wheel that goes on the axle, whatever it is called, the spacer does not slowly cut into the plastic as a piece of brass tubing might do. Also, if you glue your wheels on and some of the glue gets on the spacer, it just becomes part of the wheel and prevents the glue from going back to the bearing and gluing it tight. Not that I have ever done this.
Breaking the Record: Flyin Brian McNay (Chet) is a local autocross driver and also races slots. He holds more records on our track than anyone. Everytime I let him borrow a car he will break a track record, usually mine, and this was no exception. I USED to hold the unlimited non-magnet record with a 10.30, but he dropped it to a 10.06 which was backed up by a 10.09 and a 10.15. It was a pleasure watching the car go round.
Tearing Down: As a matter of procedure we tore the car down to show there were at that time no magnets. This is a procedure that should be done in my opinion as a matter of procedure then there can be no accusations of wrong doing. People should know that if you set a record you get torn down. It is a part of real racing and should be a part of model car racing.
Future Tests
ADDING WEIGHT
BIGGER WHEELS AND TIRES
ORTMANNS