- How to Bulletproof your Vehicle


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8 stay-tough tips

Words: Derek Buono

 

RC vehicles of all types are subjected to stresses that would destroy full-size cars if the forces were "scaled up" and applied to them. Itís truly amazing what the typical RC car can take, but all cars have their limits. This article will show you how to extend those limits and help ensure that your car makes it through all three qualifiers and the Main in one piece (or that it lasts for a full day of backyard fun without a trip to the bench). None of these tips is very complex or expensive, so why not give them a try?

Install titanium turnbuckles
Most kits come with steel camber links that are generally strong but will bend if loaded just right. Titanium simply won't bend or break (and if you do crash hard enough to tweak titanium, the turnbuckles will be the least of your broken-part worries). Lunsford titanium tie rods are the most popular and are sold in a wide variety of sizes, from itty-bitty touring-car lengths to long truck links and even fat, 1/8-scale sizes. Lunsford also offers ti hinge pins for many vehicles. If you replace the turnbuckles and hinge pins, it's less likely that one will bend or break and potentially end your run.

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image_two.jpg - 9171 Bytes Seal the transmission
Most tranny cases have a good seal, but even the tightest cases may allow dust into the tranny. A thin film of grease between the tranny halves followed by a wrapping of decal material or vinyl tape over the seam will just about eliminate any chance of grit entering the tranny. Replacing the large diff bearings with sealed bearings will also reduce the chance of contamination.
Apply thread-lock to all metal-to-metal connections
Nitro vehicles require more thread-lock because they usually have more screws that thread into metal, but all RC cars can benefit from the strategic application of thread-lock. Top spots include jam nuts that secure ball ends, setscrews in outdrives, wing button screws, diff screws and output-shaft screws in metal-gear servos. On nitro vehicles, be sure to hit the engine-mounting screws, the linkage-collar setscrews and the screw that holds the clutch bell on the crankshaft if your car does not use an E-clip. Wherever you find screws threaded into metal, apply thread-lock.

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Install captured ball cups
The ball cups included with most kits grip their ball ends well and wonít pop off unless you really clobber something. But as the cups are popped on and off for maintenance, and as they wear with use, they loosen and come off more easily than they should (such as when someone taps your car in a corner). You could replace them regularly as insurance against such mishaps, but your best bet is to install captured ball ends. GS Racing makes the parts shown, and you can also get captured ball ends from Du-Bro, OFNA and other sources. Install the ball ends with a pan-head screw or washer over the ball, and they simply can't pop off. A warning, though: if your car pops ball ends because you hit everything in sight, leave them in place; the pop-off action is probably sparing your car from having broken arms and hubs.

Eliminate hinge-pin slop
Some cars have hinge pins that extend past the suspension arms, leaving a gap between the E-clip and the arm. This allows the E-clip to flex back and snap off if it's struck. To prevent this, fill the gap by sliding an O-ring over the hinge pin before you reinstall the E-clip. If your car's arm mounts have sufficient bulk, you can get rid of E-clips altogether by using a setscrew to hold the hinge pin in place. With a drill bit of an appropriate size, make a small hole in the arm mount in line with the hinge-pin bore. Thread the setscrew into the hole, and tighten it until it holds the hinge pin in place. Don't use this tip unless there's plenty of material around the hinge-pin bore, or you'll weaken the arm mounts.

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Keep the diff's thrust bearing dirt-free
The presence of dirt is a main cause of thrust-bearing failure. Most kits have some kind of cap to keep dirt away from the thrust bearing; use it. If your kit isn't so equipped, or if you've lost the cap, try placing a piece of foam in the outdrive, over the bearing. Cut the foam slightly oversize so friction will hold it in place (here's an easy way: use a pair of pliers to clamp a concave washer against a piece of foam tire insert or similar material; the washer will cut a perfect foam plug). Install the foam in the outdrive and check for dogbone clearance; the dogbone should not be deeply squishing the foam, but it's OK if it just touches it.

image_seven.jpg - 8838 Bytes Heat-shrink CVDs
If you havenít lost a pin from a CVD yet, you're lucky. Despite the thread-lock that MIP includes with the CVDs, even the most careful builders occasionally throw a pin. Prevention is simple: remove each axle and use some heat-shrink tubing (Du-Bro offers an assortment of sizes) around the axle's ďbellĒ to capture the pin if it loosens. Just be careful not to allow excess tubing to hang over and rub the inner hub carrier.
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Flare the exhaust header
No matter how many zip-ties you wrap around your exhaust coupler or how tightly you cinch them down, couplers seem to slide off during those long Mains. You can greatly reduce the chance of this happening by flaring the ends of the manifold and exhaust pipe. Just insert a screwdriver into the open end, apply pressure to the side of the opening and give it a spin. As the photos show, this creates a "lip" on the pipe. Now the manifold and pipe have a little more "bite" on the coupler, and with a pair of tight zip-ties, they should stay in place.

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