1/10 Scale Electric Rally/Touring Car:

Ofna OB4 Pro 2 - Radio Controlled Model

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History and Info for the Ofna OB4 Pro 2:

Manufactured by Hong-Nor and distributed by Ofna circa 2000, the 4WD OB4 Pro 2 International, is belt driven on a double deck chassis, with ball differentials, coil spring over oil filled dampers, universal joint drive-shafts and came with a full set of ball bearings.

Ofna OB4 Pro 2 - 1:10 Electric On Road Car

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To race the Ofna OB4 Pro 2, it calls for fine tuning to attain better steering response and improve grip when cornering so you don't slide off the side of the track. Minute changes can make huge advancements. Our easy to understand list will show you how and lead you to the optimum Set-up to put you in front of the rest on the track.

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Radio Controlled Model Accessories:

★ Ofna OB4 Pro 2 International Chassis ★

Buying a Used Ofna OB4
Touring Car (and What to look for)

There are essentially three reasons you might want to buy a used Ofna OB4 Electric Touring Car; you may be a collector, looking to restore and display it; restore and sell for a profit; or simply restore and race an iconic vintage model. Personally, I used to get a buzz out of restoring an old clapped-out model, installing modern day electrics and maybe a few hop-ups, then showing the gang at our local club, just how competitive those old models could still be.

Cheap, pre-loved bargain models, parts and spares are always coming up for sale, but once you have made your purchase, the one thing you will always need, is an instruction manual. If not supplied with your purchase, they can often be downloaded from the Ofna website, or purchased separately on eBay. With an instruction manual, any problems with your model Touring Car you may discover, can easily be fixed.

Make a General Visual Inspection

Dampers
When you receive your used Ofna Touring Car, make a general visual inspection of the chassis, front and rear wishbones, suspension shock towers etc, for any broken parts that may need to be replaced. Then, take a screwdriver and box spanner and check each self tapping screw and nut for security, taking care not to over tighten.

Next, for those Ofna models with oil filled shock absorbers, remove them from the chassis and dismantle the coil springs. The damper shafts should push in and pull out with a smooth action. If you feel a jolt as you change direction, this means the oil has leaked out and must be topped up. At the same time, change the O-Ring seals to prevent more leakage. Also check the damper shafts for damage. If they are scratched, change them as soon as possible.

Check the Body-Shell

If the body shell of your Ofna OB4 is broken, ripped or damaged in any way, this can be easily repaired with rubber solution glue. Also, for added protection and if available for your OB4 model, fit an under guard to stop dirt and gravel entering the chassis.

Drive Shafts and Turnbuckles

Titanium Turnbuckles
Examine the drive shafts for wear and replace as required. If possible, change them for titanium. The steel shafts wear and bend too easily.

If you intend to race your OB4 Touring Car model at a competitive level, I would also recommend you obtain and fit titanium pivot shafts, turnbuckles, tie rods and steering rods.

Examine the Drive System

Drive Belts need checking at regular intervals for wear, tension and damage. If deemed necessary, adjust the tensioning pulley until the belt can be depressed in the centre by no more than around 5mm. If the belt was slack, also examine the drive pulleys for wear. The teeth should provide a well seated fit for the belt teeth and not be rounded on the corners. If the belt teeth do not fit snugly, change the pulleys as soon as possible. For top level racing it may be prudent to replace all belts and pulleys after each race meeting.

Pinions and Spur Gears

Gears are a weakness on all Touring Car RC models. Head on collisions can easily damage the gear teeth on nylon and plastic spur gears. Heavy impacts can also loosen the nuts or self tapping screws that hold the Electric Motor in Position, allowing the pinion gear to pull out of mesh slightly and rip the tops off the teeth on your spur gear. To minimise this possibility, fit bolts with locking nuts to the Electric Motor mount and remember to check them for security after every two or three runs.

Don't Neglect the Ball-Joints

Ball joints always cause problems. For top level Electric Touring Car racing, the plastic ball connectors should be checked and if deemed necessary changed after every meeting. A simple thing like a loose fitting connector popping off could easily end your race, so better safe than sorry.

Steering Servo and Servo-Saver

Servo Gears
The OB4 steering servo is also prone to damage. In high speed crash situations, the fragile gear teeth of the servo can be broken off, rendering your expensive servo useless, so be sure to obtain a good quality "Servo Saver". Check out my Servo Information article.

Stabilizers

If body roll on your Ofna OB4 is a problem, handling can be improved with the use of stabilizers, anti roll or sway bars, stiffer tuning springs and, or, thicker silicone oil in the dampers.

Don't Forget those Bearings

If your used Ofna Touring Car comes with plastic and sintered brass bushings (ring type bearings), check the shafts that run in them for wear. Dust and grit can get into these bearings and abrade the shafts. Therefore, you should replace them all with shielded ball bearings. If the model has been run with ring type bearings, you may have to change all the axles and driveshafts. For more information, take a look at my article, How to get the best from your Bearings.

Finally, good luck with your OB4 model and good racing.

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Manufacturers and Brands Catalogued, Listed and Reviewed by RC-Scrapyard.

At present, the RC Model Manufacturers, Brands and Distributors covered by us are: ABC Hobby, Academy, Acme Racing, Agama Racing, Amewi, Ansmann Racing, ARRMA, Team Associated, Atomic RC, Axial, AYK, Bolink, BSD Racing, Capricorn, Carisma, Carson, Caster Racing, Cen, Corally, Custom Works, Durango, Duratrax, ECX - Electrix, Exceed RC, FG Modellsport, FS-Racing, FTX, Fujimi, Gmade, GS-Racing, Harm, HBX, Helion, Heng Long, Himoto Racing, Hirobo, Hitari, Hobao, Hong-Nor, Hot Bodies, HPI, HSP, Intech, Integy, Jamara, JQ Products, Kawada, Kyosho, Losi, LRP, Maisto, Mardave, Marui, Maverick, MCD Racing, Megatech, Mugen, New Bright, Nichimo, Nikko, Nkok, Ofna, Pro-Pulse, Protech, PTI, RC4WD, Redcat Racing, RJ-Speed, Robitronic, Schumacher, Seben, Serpent, Smartech, Sportwerks, Step-Up, Tamiya, Team-C Racing, Team Magic, Thunder Tiger, Tomy, Top Racing, Traxxas, Trinity, Tyco, Vaterra RC, Venom, VRX Racing, WLToys, X-Factory, Xmods, Xpress, Xray, XTM, Yankee RC, Yokomo, ZD Racing and Zipzaps.

This is an ongoing project, with new and "lost in time" RC Models and Brands being added as they are found and although most of those listed above have been covered in relative detail, some are still being researched and will be completed in the near future.

RC Information and Advice:

Hints, Tips and Information

Your First Race Meeting

When you finally find a racing club near to where you live, that initial experience of stepping up onto the rostrum and looking down over the track can be very daunting. But soon, as the race starts, adrenaline will kick in and away you go. For the next five minutes, your focus is on nothing but getting your car around each corner, avoiding all the other cars on the track and just getting to the end of the race.

Maybe your batteries dumped or you crashed and the car was damaged, perhaps you didn't actually come last, whatever happened, it doesn't really matter - you are well and truly hooked.

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Hints, Tips and Information

Gearing to Win

   Just because you have the latest model, the best available batteries, the most powerful electric motor or nitro engine, doesn't mean you will go out and win everything in sight. The fastest car on the track is rarely the one that wins, it's the one that can accelerate out of corners under control, and remains consistent and efficient from the start to the end of a race.

   In days gone bye, all you had to consider was the number of mili amp hours (Mah) in your battery, and the current draw of your high powered motor. Gearing for a five minute race was a balancing act. But with the development of the new high capacity batteries, brushless motors and smart ESC, all that changed. Now, gearing is more of a matter of what suits your driving style and how quick your reflexes are on the sticks, the trigger and steer wheel of your transmitter. So, where do you start?

   At your local club track, you quickly find the right combination and set-up for your car by talking to the more experienced members. After a while, as your knowledge grows, tweaking a few things here and there can give you that small edge to keep you competitive. So, it follows that on tracks you don't know, you should talk to the locals there, who may be racing a similar model to your own, and adjust your set-up to suit.

   Gearing correctly for any given track is absolutely crucial if your car is to be competitive.

   Too high a gearing may get you in front at the start of a race, but as your motor begins to overheat and lose efficiency, that initial advantage will soon be lost.

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