No One Wanted to Fix This Mazda RX-8—So I Did

The Mazda RX-8 has a reputation. Ask any mechanic, and they’ll probably roll their eyes at the mere mention of it. It’s a car that’s both loved and feared, thanks to its infamous rotary engine—an engineering marvel that operates nothing like your standard piston-driven motor. And yet, when an RX-8 showed up at my shop, abandoned by over 300 potential buyers, I did what any reasonable person would do.

I took it on.

The Problem No One Wanted to Touch

This RX-8 didn’t run. That much was clear. But why? That’s the million-dollar question. Before diving in headfirst, I needed to assess the damage without tearing everything apart—so out came the borescope, a tiny camera that lets you peek inside the engine through the spark plug hole.

Rotary engines are a different beast. No pistons, no valves—just two Dorito-shaped rotors spinning inside their housings. It’s an elegant, compact design that allows for high revs and smooth power delivery, but it’s also incredibly fragile if not properly maintained.

The borescope revealed the first red flag: filth and gunk everywhere. It wasn’t looking good. The real problem, however, lay within a small reservoir under the hood—two-stroke oil, the lifeblood of a rotary engine. Without it, the engine can’t stay lubricated as it spins at 9,000 RPM. And guess what?

The owner never topped it up.

To be fair, it was his first car. And let’s be honest—rotary engines aren’t exactly common knowledge. But driving without lubrication? That’s a death sentence for an engine like this. Still, despite the challenges, I couldn’t help but admire his passion for the car. That’s why I decided to take on the project and, hopefully, bring this RX-8 back to life.

Tearing It Down

Once the decision was made, it was time to get to work. Pulling the engine is no small feat, and organization is key. Every nut, bolt, and component had to be cataloged to avoid a reassembly nightmare later.

With the intake manifold, alternator, and water pump off, it was time for the moment of truth. Rotary engines are essentially sandwiched together with 18 long tension bolts. Once those were out, I cracked the engine open and laid eyes on what lay inside.

Two extremely filthy rotors stared back at me. They were covered in thick layers of carbon buildup, which meant hours of careful cleaning ahead. But before I got too carried away, I needed to inspect the rotor housings—because they hold the key to whether or not this engine could be saved.

The Make-or-Break Moment

Inside the engine, the critical component is the Apex seal. This small strip of metal sits inside the rotor and scrapes against the housing as it spins, maintaining compression. If the rotor housing has any deep scratches or gouges, it’s game over.

The first housing looked promising—clean, free of deep damage, and salvageable.

The second housing? Not so much. Deep scratches, enough to be felt by hand, marked its surface. This wasn’t good. The damaged surface would eat away at the new Apex seals, causing compression issues and, ultimately, engine failure.

With no other choice, I called the owner to break the news. He had a decision to make.

A New Hope (and a Used Housing)

Three days later, the owner came through. He wanted to do it right and sourced a used rotor housing in much better condition. It wasn’t perfect, but it was leagues ahead of the old one. With that problem solved, it was time to tackle the next major hurdle—cleaning and reassembling the engine.

Every component had to be spotless, especially the rotors. These things were the worst I’d ever seen, caked in years of carbon buildup. Armed with a soft wire wheel and a hand drill, I painstakingly removed every bit of grime, ensuring that the moving parts would operate smoothly.

Once everything was clean, it was time for one of the most nerve-wracking parts of rebuilding a rotary engine—packing the rotor.

Precision is Everything

Packing the rotor involves carefully installing tiny side seals that must fit within 0.1mm tolerances—about the thickness of a human hair. If I cut even a fraction too much, the entire rebuild would be ruined.

Twelve seals. Each one needed to be measured, cut, and tested meticulously. It was a painstaking process, but after hours of work, everything was finally coming together. A bit of Vaseline was applied to keep the seals in place, and it was time to put the engine back together.

With every torque spec double-checked, every connector secured, and every vacuum line accounted for, it was time for the big moment.

The First Start (And a Major Letdown)

Key in the ignition, everything set.

Click. Nothing.

The battery was dead. Swapping in a fresh one didn’t help either. Eventually, I realized I’d left one ignition coil unplugged—rookie mistake. But even after correcting that, the RX-8 still wouldn’t start.

Days passed. I went to South Korea, came back, and the car still sat lifeless. After replacing the spark plugs and trying a booster pack, I had a revelation—the starter motor.

It sounded weak, like it couldn’t spin the engine fast enough. If the starter wasn’t cranking at the right speed, the rotary simply wouldn’t fire up. So, I swapped in a stronger, newer starter and braced myself for yet another attempt.

Success! Neutral. Ignition. Vroom.

The RX-8 roared to life. Smoke filled the shop, a signature of the Vaseline burning off, but it ran. Smooth, healthy, and alive once more. I couldn’t believe it.

After a thorough check for leaks and fluid levels, I took it out for its first drive. It pulled strong, idled nicely, and showed no signs of the disaster it once was.

A Happy Ending

The owner was ecstatic when I told him the good news. He’d have his beloved RX-8 back, and this time, he’d know exactly how to take care of it. As for me? This project was a wild ride, but I walked away with a newfound appreciation for these misunderstood machines.

So, what’s the takeaway? Never give up on a car you love.

If you enjoyed this journey, make sure to check out my YouTube channel for more automotive adventures.

YouTube: Herr Moritz

Until next time, keep wrenching.