Prep for cold weather

Radio Control Car Action, Mar 2003 by Bess, stephen

PISTON POWER * EXPERT ENGINE ADVICE

What can you do in winter if you live where outdoor RC is impossible?-pack up your nitro RC equipment and go cold turkey until warm weather arrives? I think not!

Winter can be a fun time to blast around a parking lot or a backyard with a nitro-- powered RC vehicle, but you have to prepare for this. Getting ready to run in snow and cold weather requires more than simply wrapping a set of earmuffs around your cranium and tossing on a parka to stay warm; you must prepare your nitro vehicle if you want it to survive. Here's how to have fun with your nitro car or truck when it's freezing outside -- without damaging any components.

PREPARE FOR HIBERNATION

ELECTRONICS PREP

RC electronics are the most vulnerable to cold. When snow and ice are subjected to engine heat, they melt into electrical components' worst enemy-water. To protect your components, seal them completely against moisture.

1. Some nitro vehicles have "sealed" receiver boxes, but they aren't completely moisture-proof. Protect your radio receiver by inserting it into a large balloon, and seal the balloon's opening with a dab of Shoe-Goo or silicone sealant and a zip-tie. Allow the sealant to cure overnight, and your receiver will be virtually waterproof.

2. Next, seal the servo cases with a thin bead of Shoe-Goo; it's easiest to place dabs around the seams of the case and then spread it thinly with a finger. It's also a good idea to seal around the rubber grommet where the wires exit the servo housing. Sealing the servo's output shaft will require a trip to the hardware store for O-rings. The O-rings should be slightly larger than the servo output shafts diameter and thick enough only to just fill the gap between the servo-saver and the servo housing. A little grease will lubricate the O-rings and help to create a better seal.

3. Finally, seal the receiver battery inside a balloon using the same technique as you used for the receiver. If you can, cover the switch harness with a rubber switch boot, or seal its seams with Shoe-Goo. Now your electronics are protected and are ready to battle the snow and ice.

ENGINE PREP

Your nitro engine may seem impervious to cold-weather woes, but low temperatures can damage internal components. It's obvious that overheating a 2-stroke engine can cause premature wear and even failure, but few of us realize that over-cooling a nitro engine can cause as much damage, or even more. Engines that operate in the 220- to 250-degree F range have been broken in so that their ideal piston/sleeve fit is in that temperature range; running at lower temperatures will wear the components prematurely because they won't heat enough to expand properly for the correct fit. When the engine is very cold, the piston can get stuck in the top of the piston sleeve and snap the connecting rod.

To prevent your engine from running too cold during the winter, you may prep it one of two ways:

1. The most practical option is to apply shiny, silver aluminum tape to the heat-sink head to retain heat. (This tape is typically used to seal joints in household ducting, and you'll find it at most hardware stores.) Start by applying a length of tape that will just wrap around the front half of the cooling fins; cover them from top to bottom. Modify the amount of tape used by monitoring engine temperature: use more tape to increase temp and less to reduce it.

2. If you've ever replaced a damaged cylinder head or upgraded to an aftermarket one, you can modify the old head to run in the cold. To retain enough heat, cut some of the fins off the cooling head. Fewer cooling fins will mean less heat dissipation; in very cold weather, cutting fins off the cooling head will bring the engine's operating temperature up to normal. Start by cutting just a couple of fins off the head; then check your engine's running temperature regularly. Once you've arrived at the proper number of cooling fins for optimal engine temperature during typical winter weather, you'll be able to simply swap to your cold-weather head during the winter, and you'll still have an engine you can use when things warm up again. This option is expensive, unless you have an extra head for your engine.

TUNING AND DRIVING HABITS

1. Even when it's cold, it's very important to keep the engine temperature up in the low to middle 200-degree F range. It's also very important to understand that I'm not suggesting that you tune your mixture to achieve a specific engine temperature; your fuel mixture needles are NOT thermostats. Instead, you should tune for maximum performance and then increase or reduce cooling to bring engine temp to within an acceptable range. In a full-size car, fuel mixture is not used to regulate engine temp. The radiator, thermostat and coolant regulate temperature, and the fuel mixture is simply regulated for optimum performance, as it should be with nitro engines. Think of the nitro engine's cylinder head as being equivalent to a radiator, thermostat and coolant system in a big car. If you restrict the airflow by using tape or cutting off a few cooling fins, you'll be able to regulate your engine's temperature somewhat.