Hey car enthusiasts! Ever dreamed of diving deep into the world of the iconic Mazda RX-7? Specifically, the FC (second generation) and FD (third generation) models? Well, you're in the right place! We're about to embark on an awesome journey of RX-7 FC and FD chassis repair, exploring everything from rust removal to suspension upgrades. Get ready to get your hands dirty, learn some super cool stuff, and maybe even save some serious cash in the process. Ready to wrench on your own RX-7? Let’s dive in!

Understanding the RX-7 FC and FD Chassis

Alright, before we get our hands dirty, let's get acquainted with the RX-7 FC and FD chassis. The chassis is essentially the car's skeleton, providing the structural foundation upon which everything else is built. It’s what keeps your RX-7 rolling straight and handling like a dream (or at least, should!). The FC, produced from 1986 to 1991, featured a unique design that was a significant evolution from the original RX-7. The FD, built from 1992 to 2002, took things to a whole new level with its sleek lines, improved aerodynamics, and a stiffer chassis. Both models, while sharing the RX-7 spirit, have their own quirks and common problems that you, as an RX-7 owner (or aspiring owner), need to be aware of.

Common Chassis Issues: Rust, Rust, and More Rust

Now, let's be real: Rust is the bane of any classic car's existence, and the RX-7 is no exception. These cars are getting older, and with age often comes the dreaded red plague. Common rust areas on the FC include the rear quarter panels, the floor pans, the frame rails, and the strut towers. On the FD, you'll want to keep an eye on the rear quarter panels (again!), the frame rails, the front chassis legs, and the areas around the sunroof (if equipped). Rust isn't just an aesthetic issue; it can compromise the structural integrity of your car, leading to safety concerns and potential failure during inspections.

Diagnosing Rust: A Deep Dive

So, how do you diagnose rust? The best way is a thorough inspection. Get under your car with a good light, some safety glasses, and a screwdriver or pick. Start by poking around in the usual suspect areas. If the metal flakes away or the screwdriver goes through with minimal effort, you've got a problem. Also, pay attention to any bubbling paint or areas where the paint is flaking or peeling, as these are often early signs of rust. Don't forget to check the inside of the car, too, especially the floorboards and the trunk. If you find rust, don't panic! It’s manageable. But it’s crucial to address it promptly to prevent it from spreading and causing more damage.

Chassis Reinforcement and Upgrades: Making Your RX-7 Stronger

Beyond rust repair, you might consider reinforcing your RX-7's chassis, especially if you plan to track the car or subject it to some spirited driving. Stiffer chassis translates to better handling, improved responsiveness, and overall a more enjoyable driving experience. Here are a few popular reinforcement options.

• Weld-in Subframe Connectors: These connect the front and rear subframes, increasing torsional rigidity and reducing chassis flex. They’re a fantastic upgrade for any RX-7, improving handling and reducing the likelihood of cracking in high-stress areas.
• Roll Cages/Roll Bars: Primarily for safety, roll cages and roll bars also significantly stiffen the chassis. They’re essential if you plan to track your car or participate in any motorsport events. Be sure to choose a cage that meets the regulations of your local racing organization.
• Strut Tower Braces: These connect the tops of the front or rear strut towers, further stiffening the chassis and improving handling. They're relatively easy to install and provide a noticeable improvement in responsiveness.

Essential Tools and Techniques for RX-7 Chassis Repair

Alright, now that we know what we're up against, let's talk tools and techniques. Having the right tools and knowing how to use them is essential for any successful chassis repair job. You don't need a professional workshop to get started, but investing in quality tools will make the job much easier and the results much better. Safety first, though!

Must-Have Tools for the Job

• Welder: A MIG welder is the most common and versatile choice for chassis repair. Practice your welding skills before tackling any serious repairs. Get some scrap metal and practice making solid welds. It's a skill that will pay off big time. You don't have to break the bank for a welder; there are many affordable options available for hobbyists.
• Angle Grinder: An angle grinder is your best friend for cutting, grinding, and removing rust. Invest in a variety of discs, including cutting wheels, grinding wheels, and wire brush attachments.
• Wire Brush: A wire brush is essential for removing rust and cleaning metal surfaces before welding or applying any protective coatings. Consider a hand-held wire brush, a wire brush attachment for your drill, and a wire wheel for your angle grinder.
• Hammer and Dolly Set: For shaping metal, you'll need a good hammer and dolly set. This allows you to repair dents, smooth out welds, and restore the original shape of your RX-7's body panels.
• Protective Gear: Safety glasses, a welding helmet, gloves, and a respirator are non-negotiable. Welding and grinding can be dangerous, so protect yourself from sparks, fumes, and flying debris.

Step-by-Step Chassis Repair Guide

Okay, let's get down to the nitty-gritty. Here's a basic guide to chassis repair. Remember, this is a general overview; specific steps may vary depending on the extent and location of the damage.

1. Assessment and Preparation: Carefully assess the damage. Determine the extent of the rust or damage, and mark the areas that need to be repaired. Clean the area thoroughly with a wire brush or grinder to remove all rust, paint, and contaminants.
2. Cutting Out the Damage: Use your angle grinder or a cutting torch to carefully cut out the damaged metal. Be precise, and try to follow the original contours of the panel.
3. Fabricating or Sourcing Replacement Panels: If you're a skilled fabricator, you can create replacement panels yourself. Otherwise, you can purchase pre-made repair panels from various RX-7 parts suppliers. Make sure the replacement panel fits properly and matches the original contours.
4. Welding the Replacement Panel: Carefully weld the replacement panel into place. Use short, controlled welds to minimize heat distortion. If you’re not experienced, practice welding on scrap metal first.
5. Grinding and Finishing: Grind down the welds to smooth out the surface. Use a hammer and dolly to shape the metal and restore the original contours. Use body filler to smooth out any imperfections, then sand the surface until it’s perfectly smooth.
6. Priming and Painting: Prime the repaired area to protect it from corrosion. Then, apply a coat of paint that matches the original color. Use multiple thin coats for the best results.
7. Rust Prevention: Apply a rust-preventative coating to the inside of the repaired panel to prevent future corrosion.

Suspension Upgrades and Chassis Enhancement

Beyond basic repairs, you can enhance your RX-7's chassis performance with suspension upgrades. There are numerous options, from simple bolt-on modifications to more extensive overhauls. Upgrading your suspension can significantly improve handling, ride quality, and overall driving dynamics. It can also help to reduce body roll and improve the car's responsiveness. Here are some popular suspension upgrades:

Coilovers

Coilovers are a popular upgrade that combines the spring and damper into a single unit. They offer adjustable ride height, damping, and sometimes spring rates. Coilovers can significantly improve handling and allow you to fine-tune your suspension for your driving style and track conditions. They're often a great investment for those who want to get the most out of their RX-7.

Sway Bars

Also known as anti-roll bars, sway bars connect the left and right suspension components, reducing body roll during cornering. Upgrading your sway bars can make a noticeable difference in handling, especially in corners. They are relatively easy to install and offer a great bang for your buck.

Bushings

Replacing the rubber bushings in your suspension with polyurethane or solid bushings can improve handling and responsiveness. Rubber bushings can degrade over time, leading to play in the suspension and reduced performance. Stiffer bushings can improve control and reduce unwanted movement, but they may also result in a firmer ride.

Strut Tower Braces

As mentioned earlier, strut tower braces connect the tops of the front or rear strut towers, further stiffening the chassis and improving handling. They are relatively easy to install and provide a noticeable improvement in responsiveness. These are often a great upgrade for those looking for a simple bolt-on improvement.

Resources and Further Reading

Alright, folks, that's a wrap for this guide! Remember, working on your RX-7 can be a rewarding experience. It gives you a deeper connection to your car and allows you to understand it from the inside out. Now go ahead, get your hands dirty, and enjoy the process!

Here are some resources that you can use to learn more about RX-7 chassis repairs.

• RX-7 Club Forums: These forums are a great place to connect with other RX-7 enthusiasts, ask questions, and share your experiences.
• Online Parts Suppliers: These suppliers sell a wide range of parts and repair panels for RX-7 models.
• Service Manuals: If you don't already have one, a service manual is a must-have for any RX-7 owner. It provides detailed information on all aspects of your car, including chassis repair.

So there you have it, a thorough overview of RX-7 FC and FD chassis repair. Remember to always prioritize safety, and don't be afraid to ask for help from experienced mechanics or other RX-7 enthusiasts if you get stuck. Happy wrenching, and enjoy the ride!