Sometimes there are problems with the way a slot car is made, but for some reason known only to the buyer he does not wish to return it to the dealer.  One of these common problems is that the cars are not running smoothly and  sound rough because the engine is moving vertically in the chassis engine mount.  I have had this problem often with cars that with an inline engine configuration, but only once with a sidewinder.  There are multiple ways of fixing the problem, but the easiest solution is going to be examined.  The problem itself is not peculiar to any particular brand, but has been found in some of the SlotIt, SCX, Scalextric, Fly, and Ninco cars in my stable.

Detecting the Problem

    The first thing needing mentioned is that the problem is not always easy to detect, but it is easy enough to fix and the fix will not hurt a car that does not have the problem.  In other words if you do this to a car that has an engine that is not loose in its engine mount, it is not going to hurt anything.  So how do you detect the problem?  One sure sign is that there is a lot of gear noise at high RPMs, but when you run the car at low RPMs or turn the wheels by hand, everything feels fine.  Another way is to remove the body and hold the rear of the car in the air and watch the pinion gear which is the gear on the shaft of the motor.  If the motor or the gear appear to be moving up and down, then you have the problem.  The less the movement the better and no movement is best.

    I have a Ninco Mc Laren GTR that has the Fina livery (the one with the British flag on the back and the words Fina across the front).  Cool car, but it always sounded funny and would hop every so often under full power.  When I removed the magnet, which is a good thing to do in debugging a car, the hop became more pronounced.  Magnets sometimes mask a problem and it is easier to see what is happening when they are removed.  The first move I made was to sand the wheels to be sure they were round, but this did little to fix the problem.  The next step was to remove the body and watch the car run around the track.  What happened was that the motor popped completely out of its bracket.  It turns out that Ninco, the car's maker, had fitted a piece of plastic to the body that dampens this to a degree and prevents the motor from coming out when the body is attached. I loosen my bodies slightly as tests show that a car with this done will be faster, but with the body loose the engine was allowed to move more.  When the engine moved the gears did not mesh correctly and so there is a lot of gear noise.

Fixing The Problem

    How does one fix this problem?  Either one makes a spacer that tightens the engine in its bay or one glues the engine in place.  Usually I do the latter except in the case of ProSlot and SlotIt cars as the engine bracket floats in the chassis and the spacer works better.  I have not had this problem with the new SlotIt Porsches, but did have it with the original Audi R8C.  People often use CA glue (Cyano Acrylate), but the most effective fix is to get out the hot glue gun and run a generous bead of hot glue down each side of the motor and let it dry.  Do not get the glue near the motor shaft or the gears.  CA glue has a tendency to make the plastic brittle and it will break after time, but hot glue on the other hand, holds very well and can be removed more easily if you wish to change engines.  If the glue comes loose then you just take it off and run a new bead.

    Note in the following picture where the hot glue was applied and how much was used.  If the motor moves, add more glue until it stops moving.  If glue does not cure it then you have major problems that are beyond the scope of this fix.

    Is the car faster?  Yes.  Is it quieter? Yes.  Is it easier to drive?  Yes, because anytime a machine works more efficiently, it is a better machine. If are confused and live in Cincinnati you can bring your cars over to my house and I will show you how to do it.  I am in the phone book.  The rest of you should move to our fair city and help make it the slotting capital of the world.