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Rollcage Installation - Caged FishOur Bracket Car Project Gets A Rollcage From the June, 2007 issue of Mopar Muscle By Dave Young Photography by Dave Young
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Racing your Mopar can be a challenging and exciting hobby as long as you take the proper safety precautions. We all like going fast in our cars, but an accident at the high speeds that most Mopars attain in the quarter-mile can be disastrous, so safety equipment must be added to a race car to minimize the risk of driver injury. Good seat belts, a helmet, and long pants are mandatory when racing even the mildest street car, but what if you want to go faster? Since the goal for our project Barracuda is some solid 10-second timeslips and speeds at around 130 mph in the quarter, we need to ensure the car is both safe to drive and able to pass NHRA technical inspection since we'll be racing at several sanctioned tracks. In this article, we'll show you the proper way to install a rollcage in any car, and we'll make project B-3 safer, stiffer, and more consistent in the process. While nobody goes to the track planning to wreck their car, the fact is that stuff happens. Accidents are a part of life, and the racetrack-while considerably safer than driving on most highways-is no exception. Even if you're a great driver and your car is in top condition, you never know when the brand X guy or girl in the next lane will blow their motor, cross the center, and run into you, so precautions must be taken.  Adding a rollbar or rollcage...  Adding a rollbar or rollcage to your Mopar offers many benefits, including improved safety, stiffness, and the ability to pass strict NHRA tech when you're at the track. Follow along as we show you how to install a rollcage in your Mopar.  Anytime you perform chassis...  Anytime you perform chassis work that involves welding, it's important to be sure the frame is level both side-to-side and front-to-back. We used a level on the rocker panel at the doorjamb, then the top of the cowl to ensure our car was level during the installation. Remember, if the chassis is not true when the cage is welded, the cage will permanently hold the chassis in its warped state causing suspension problems.  Sheetmetal can be used to...  Sheetmetal can be used to shim the car on the jackstands until it is level. The greatest safeguard we take when building a race car is to add a rollcage. The rollcage is designed for one purpose-to save the driver from injury or death in case of an accident. Even so, some racers and especially street enthusiasts are reluctant to add the weight of a cage to their cars. Years ago, the NHRA and other sanctioning bodies mandated that cars of a certain speed be equipped with a rollcage. So we know why we have to do it-to be safe and because the NHRA says so-but a rollcage can also benefit a race car in other ways. If installed properly, a rollcage will add significant chassis stiffness, which equates to more consistent elapsed times and reaction times, and less wear and tear on the car. While a rollcage can be manufactured out of raw tubing, there is a better way. Since our shop isn't equipped with a tubing bender, we decided to purchase a rollcage kit from Competition Engineering for our car. Competition Engineering makes rollbar and rollcage kits for all popular Mopars, which makes it easy to add a cage to any car. Our Competition Engineering A-body kit included all the bars to install a 12-point rollcage, and the main components were prebent, only needing to be trimmed to size before installation. Since the kit only costs a minimal amount more than the raw tubing itself, it's well worth the few extra dollars not to have to worry about bending the tubes ourselves. The only real choice we had to make was whether to fabricate our cage out of chrome-moly tubing or out of mild steel. While chrome-moly is stronger, and therefore lighter since thinner wall material can be used, it does require a TIG welder, which we don't have. A mild steel cage is a little heavier, but is easily welded using our Lincoln Electric MIG welder. Since this is a bracket car, the weight savings of chrome-moly just doesn't justify the extra cost and hassle of welding chrome-moly tubing, so we opted for a mild steel kit. Regardless of which material you choose for your cage, check the rules of the sanctioning body in charge of the track where you race. In central Florida, most of the local tracks are NHRA sanctioned, so we checked the rulebook to ensure our cage met the minimum tubing thickness requirements in the rules. Generally, companies like Competition Engineering keep abreast of any rule changes, ensuring their product conforms to the latest rule revisions and will give many years of good service. Even so, we used our NHRA rulebook as a reference, along with the instructions that came with the rollcage kit, to properly install our cage. We suggest doing as we did, using the cage instructions as a reference, but installing it by the rules in the NHRA rulebook. If there is ever a question of how or where to install a bar, the rulebook should be the final authority. After all, it's an NHRA official who will be performing the technical inspection at the track, so if the cage is installed by the guidelines in the NHRA rulebook it shouldn't have any trouble passing inspection. Even though the rules dictate how our rollcage is installed, there is still some leeway to install the cage so it best benefits the race car. By installing certain bars, like the main bar, over key areas of the unitbody frame, significant rigidity can be added to the car. A more rigid car will transfer more power to the back tires, be more consistent, and flex less, which greatly contributes to a long service life. The benefits of a rollcage aren't limited to race cars, powerful street cars will also gain rigidity and consistency with the addition of a cage.  Since we plan to replace our...  Since we plan to replace our glass with clear, lightweight polycarbonate, we decided to go ahead and get the windshield and back glass out of the way.  We began by fitting our bars...  We began by fitting our bars with the main rollbar. The placement of this bar is important as all the other bars will attach to it. NHRA rules say the main bar must be no further than 6 inches from the driver's helmet. With the seat bolted in position, we used a plumb-bob and string to locate the main bar front-to-rear.  To center the main bar side-to-side,...  To center the main bar side-to-side, we simply measured from the bar to the inside of the rear door panel area.  Since our Barracuda incorporates...  Since our Barracuda incorporates a unitbody frame and doesn't have OEM framerails, the rules dictate that all the bars be welded to 6x6-inch steel plates, 11/48-inch thick, that are welded or bolted to the car's floor. These plates were provided in our kit. Instead of welding our main bar to the rear floor, we welded it to the stiffer, under-seat area where it will reinforce our torque boxes, stiffening the area of the leaf-spring's forward mount.  With our main bar located,...  With our main bar located, and the metal plates welded to the floor, the main bar can be tack-welded in place. We've found it best not to completely weld anything until all the bars are fit and tack-welded in place.  With the main bar in place,...  With the main bar in place, we then fitted the main hoop of the cage. This hoop should be as tight to the roof of the car as possible without interfering with the headliner if your car is so equipped. Since our car will see race duty only, we won't run a headliner. In either case, however, the driver's head/helmet should never be above the main hoop while in driving position. Once in position and level, tack the main hoop in place.  Fitting the front bars is...  Fitting the front bars is trial and error. The bars in the kit are long enough that they'll need to be trimmed to fit. Using a sharpie to mark the final location helps to locate the plates that will be welded to the floor.  Once fitted, the location...  Once fitted, the location of the front bars was marked on the main hoop of the rollcage.  We decided to locate the forward...  We decided to locate the forward down supports of the main hoop over the front frame of the car, close to where the frame connectors attach to the front frame. This will provide additional support in case of a rollover accident, keeping the frame bars from punching through the floor of the car. An additional benefit is the extra stiffness these bars will provide.  Since the front down bars...  Since the front down bars must also be welded to a metal plate, then the floor, and since the front floors have a contour, we had to bend the plate to fit. This was easily accomplished with a hammer and vice.  Once our forward plates were...  Once our forward plates were fitted correctly, they were also tack-welded in place, then the forward down bars were welded to the main hoop and the floor plates. This forms the foundation of our cage, so then we could begin fitting the additional bars that make up the 12-point rollcage.  The rear bars should be placed...  The rear bars should be placed over the car's rear framerails for maximum support. We like to get them as close to the rear leaf-spring mounting area as possible to support this high-stress area. Again, where they attach to the floor they must be welded to the metal plates provided with the kit. Be sure to grind away the paint for a clean weld.  After marking the center of...  After marking the center of the frame-rail under the main rollbar, we used a plumb-bob and string to determine where to locate the rear bar on the main rollbar. Doing it this way ensures the rear support bar will be directly above the rear framerail of the car.  While all the tubes in our...  While all the tubes in our Competition Engineering rollcage kit were prebent, most are left long so they can be trimmed for a tight fit. A good metal cutting saw is mandatory to fit the bars.  Installing a rollcage isn't...  Installing a rollcage isn't really an exact science. In fact, we made most of our measurements with a simple tape measure. Just remember to measure accurately and avoid cutting any of the bars too short. Cutting the bar a second time is a lot easier than trying to add metal to a bar that you cut too short.  We used a combination ruler/level/angle...  We used a combination ruler/level/angle finder to find and transfer any angles to the tubing before cutting it to size.  Since both the NHRA rules...  Since both the NHRA rules and the instructions called for an X-brace from the main rollbar to the rear floor, we decided to install ours to the floor just above the rear shocks. This is another area where the suspension reacts, so supporting the floor here will add to the overall stiffness of our chassis.  Since we installed frame connectors...  Since we installed frame connectors in our car, we welded the required additional bar from the main rollbar to the frame connector for additional support. If you don't have frame connectors, this bar is installed to the floor with another metal plate.  The diagonal side bar, or...  The diagonal side bar, or door bar, is welded from the main rollbar to the forward down bar where it attaches to the metal floor plate.  The cage needs to be connected...  The cage needs to be connected to the car's forward frame, and we've found this to be the easiest way to do it. By passing a bar from the forward down bar, through the firewall, and welding it to the front framerail directly behind the upper control arm, we triangulated the frame in the area where we removed the inner fender for the headers.  From the inner fenderwell...  From the inner fenderwell you can see how we had to cut the firewall to pass the forward bar through. We'll cut a sheetmetal patch to seal the firewall when the cage is finished. This forward bar greatly improves the strength of the forward framerails, and also protects the driver's lower legs in the event of an accident.  Before welding this in place,...  Before welding this in place, the driver should be in driving position to ensure this bar passes midway between the driver's shoulder and elbow.  Once all the bars are tack-welded...  Once all the bars are tack-welded in place, we used our Lincoln Electric mig welder to finish weld all of the joints. We aren't welding experts, but by using the reference guide inside our welder to set amperage and wire feed speeds, we ended up doing a decent job.  Remember, pretty welds aren't...  Remember, pretty welds aren't always good, and good welds aren't always pretty. The key is to get enough heat in the weld to fully penetrate the base metal. Our welds aren't the prettiest, but they have good penetration, which is more important than looking pretty. Weld short beads at intervals, moving around the car, so that you don't heat warp one area. This is similar to stitch welding sheetmetal body panels to avoid heat warpage.  Even if your welds don't look...  Even if your welds don't look pretty, don't grind them. The NHRA won't let you through tech if your welds are ground off. If you really screw one up, the correct way to repair it is to completely grind out the weld and weld it again.  Since the rollcage is made...  Since the rollcage is made from untreated, raw, mild steel, it begins rusting very quickly, especially after it's been touched as the oil in human skin accelerates the process. After we had our cage installed and welded, we sanded and treated the cage and floors with rust inhibitor to prep them for paint.  Once painted, the cage looks...  Once painted, the cage looks great, way better than the rest of our car at this point. Follow along in future issues as we finish the interior of our project, wire and plumb the car, install a bulletproof drivetrain, replace the glass with polycarbonate windows, and head to the track for some testing. It's a lot of work, but project B3 will be at the track before you know it!
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