By Sean McCreery.

Straight out of the Box or after hundreds of laps of racing, Slot Cars need a reasonable amount of work to get the best out of them. So if you are finding yourself off the pace, you may have to spend a little time and effort to get back on the podium.

Inspection of the Rear End

The rear axle is the most critical part of a Slot Car; this one component will determine where you place after a hard session of racing. First unscrew and remove the chassis from the body. Then remove both of the rear tyres. Hold the Model up so you have a good view of the rear rims and axle. Rotate the axle at a steady rate and look for any irregularities.

Things to look for

Grab each rim, gently try and rotate each rim in opposite directions. This will pick any loose rims on the axle, if you find a loose rim, it will need to be glued. Also check the rims for defects, especially for cracks in their hubs. Check how well the bearings are seated in their holders, by gently moving the axle up and down and side to side. It’s no big deal if they move a little, in most cases they can be effectively glued. Check for any slop between the axle and bearings. Some of the Slot Car makers have oversized bearings; these may need to be changed to tighter fitting bearing. Remember your main aim is to get the axle spinning as true as possible, by eliminating any movement. You will also find some axles are very soft and they will wear faster than others. Sometimes overlooked, the crown gear should be checked for defects. It pays to check that it’s seated on the axle solidly. Hold the gear while turning one of the rims gently. If it moves it will have to be glued into position. The sidewinder configuration is often prone to stripping rear drive gears away from the axles, so it will pay to glue it before you go racing.

Preparing the Rear End

If you find lumps on the rims, from the moulding process, they can be filed down and then sanded back to a smooth surface. Run the Car, by placing it over the slot. Tape down the throttle so it runs at reasonable speed. Using a fine sandpaper (80Ogrit), gently dress each rim. Glide the sandpaper over the surfaces of the rim; any vibrations should disappear once the rim is round. If you find any wobble in either rim you are in big trouble! Slight wobble or run-out may be sanded out. Some guys will tell you that wobble is Ok, arguing the tyres can be sanded to compensate for any irregularities. But what if the tyre spins on the rim you end up with an egg shaped tyre. It’s best to start with a perfect rim even if the tyre moves the surface should stay reasonably round. Once you are satisfied with the axle and rims etc, they should be glued into position. Carefully unclip the axle, trying not to put pressure on to the rims. When out, carefully remove the two rims. Now is the time to change the bearings if required. Apply a small amount of superglue to the axle ends. Then evenly press the rims back on to the axle, paying attention to the wheel track. (make sure you press them on to their original position) To install back into the Car, apply a small amount of glue to the bottom of the bearing holders. Carefully clip the axle back into the chassis. Make sure you rotate the axle to check it moves freely, before the glue sets. Now would be a good time to apply a small amount of oil to the gears and bearings. The last step is to carefully roll the tyres back onto the rims. Some tyres are loose fitting on the rims; these may need a small amount of glue to stop them spinning. Make sure the tyre is centered on the rim sometimes it will sit up on one side if not centered. Hold the Car over the slot again, and get out a coarse grade of sandpaper and lightly sand both rear tyres.

Track testing

The final step is to track test your Car. Accelerate down a long flat straight, look for any movement in the back end. The Car will hop if the tyres are not sanded properly. When cornering check the Car slides well and the tyres are not grabbing. To eliminate this you may have to round of the outer edge of each tyre by sanding.

Inspection of the front end

You will need a setup board for this, (a piece of flat timber with a slot in it). The main aim of this is to check the ride height of the guide and front axle. Most slot heads like their front tyres just touching the setup board. This can be adjusted in a number ways. Flatten the braid well before placing the car onto the Setup Board, look from the side and check how the tyres are sitting on the board.

Adjusting the front end

The most common way to adjust the front tyre height is to sand down the tyres to the right diameter. Although on some cars, this can result in a lot of sanding. Depending on your Race Rules you may be able to modify the travelling distance in some way. Over the years 1 have seen a variety of spacers used, mainly to lift the axle up slightly. Others, 1 have seen, involve sleaving the axle to a set height. To sand the front tyres, it pays to have an old rim mounted on an axle. Place the axle in a hand drill, then roll on the first of the front tyres. Run the drill at speed and sand the tyres to the desired diameter. Use a coarse grade of sandpaper, although be prepared for rubber flying everywhere, you may end up with more rubber on yourself than on the rim.

Checking the Guide

I have found some guides are very loose in their holder. This movement may result in the car deslotting unexpectantley. The easiest way to correct this is to try and prise the two tabs apart on the guide shaft. Unfortunately they tend to spring back, some guys 1 know use a small screw to keep the tabs wedged apart, resulting in a tighter fit.

Checking the Gearing

With new cars it pays to check the pinion is tight on the shaft. All motors will need some running in before they can be raced. This is a good time to mesh the pinion and crown gears better. Some cars will appear to be very tight or rough in the rear end, this may indicate the gear mesh is not quite right.

Tune the Gear

I like to accelerate the gears wear slightly, by using an abrasive paste. Toothpaste can be used, just smear some paste on an UN-oiled gear. Run the Car for a few minutes and keep applying the paste. Make sure you wash off all of the paste when finished, dry then oil the gears. You should be able to note an improvement in mesh.

Preparing the body

Slot Heads spend so much time on the running gear, they often forget about the top half. First off, cheek for any loose parts. Depending on your racing style it is some times wise to remove things like mirrors and other fine detail that may end up littering the track. Some guys use a clear coat paint to protect the paintwork and livery. Most racers I know leave their Car's body loose on the chassis. They lightly sand the areas of the body, where chassis touches. This setup can improve handling slightly, by changing the weight distribution when cornering. But to get the most out it you must undo the mounting screws slightly.

Maintenance

Depending on where you race, you will need varying degrees of maintenance. Those who race on painted craft wood surfaces need to a lot more work than plastic track Racers. It is also dependent on the amount of track time you get.

Cleanliness

So much foreign material finds its way into Slot Cars. Things like hair, rubber and dust can all get into the car and reduce your performance, especially if it finds its way into the gearing and motor. Also you may have been pumping oil into your Model, this sometimes finds its way into the motor and onto your tyres. Use an old toothbrush to brush out any material from the chassis and body. Pay particular attention to the gears, remove all material from the teeth. A rag wrapped around a small screwdriver can be used to mop up any excess oil that may be on the chassis.

The Motor

If your motor has lost its punch, it may have a variety of faults. Firstly it may be full of oil, or it may have a fault with the windings or brushes. It's going to require a closer look. Remove the motor from the car, by easing it out of its holder and carefully remove the wires from the guide. Most models have the S-Can type of motor, the following description applies to this motor. Other Motors need a slightly different approach, but the basic principle applies. Once out, remove the pinion from the shaft. You will need the Ninco Puller for this. With a small screwdriver prise the two tabs of the Can, away from the motor's end bell. The next stage can be a bit tricky, so take care. Separate the can and end bell by puffing in opposite directions. The two spring loaded brushes should be eased over the armature and washers.

Preparing the Motor

Once out, check the armature's segments. They should be clean, free from carbon and oil. With a clean rag dipped in metho, wipe the armature. Make sure there is no rubbish left in between the segments, they can short out the motor. Using a very fine grade of wet and dry (1200+) gently dress the armature. This can be done by rotating the shaft while holding the wet and dry around the copper segments. Generally motors won't need too much sanding, just a clean up. The brushes should be checked, by looking for chips in the carbon. The springs should be checked that they are in the right position. For Johnson type motors check the brushes move freely in their holder. Also check the brushes have not worn down too far. When you assemble your motor gently ease the armature past the two brushes. Before you lock the End bell into position, it pays to check the shafts end to end movement. The shaft should not move more than 0.5mm if you find any excess play, the shafts stops can be adjusted with the Ninco puller.

The Braid

To maximise performance the braid should always be kept clean. You have to maintain good current flow through to the motor, to get the most out of your Car. A good way to see how your Braid is performing is to turn out the lights. All that sparking under your car may indicate poorly contacting braid. Use Metho or WD40 to clean the two strips of braid, a toothbrush can be used in to clean and at the same time flatten the braid. If they are too far-gone don't hesitate in replacing them. While you are working on the guide it sometime pays to check the wires are connected to the eyelets soundly. Gently pull on the wires and see if the wire or lugs pull out too easy.

The Tyres

Always keep an eye on tyre wear, especially on painted craftwood tracks. If you are about to do some serious laps, make sure you have got the rubber to go the distance. Performance of some cars is effected by the tyres diameter. Tyres with a lot of ware will sit low at the back. If it is a magnetic Car then you will have a lot more down force, this may slow the Car down.

Cleaning the Tyres

By keeping the tyres clean you will maximise grip, they may be coated with oil or grime. I have seen a multitude of ways to clean the tyres, from licking them to the use of other grip enhancing solutions. I think the most common method is to spray them with "WD40 then wipe them off, make sure you let them dry a couple of hours before you go racing.

Model presentation

Always try and keep the body looking as good as possible. Replace and repair any missing parts from race to race. Clean the body, removing marks and grime from the top. You could use a polish if necessary to regain the cars shine. When storing the Car avoid heat sources, that means not leaving it on the back seat of your 1 1 scale Car in the middle of summer.

Disclaimer

All items in this article are suggestions only. There may be other Turning methods not covered in this article. Any replacement parts must be within your Race rules. Do not alter the gearing ratio or the motor revs with out consulting your Rules. Cleaning the motor won't guarantee your Car will get any faster. There is sometimes a small difference in motor performance between motors of the same make.

Happy Racing