Imagine you are lucky enough to own a 1982 Mazda RX-7 sports car. One of the last great rotary machines Mazda ever produced. Now imagine the engine is dead, but rather than getting a complete engine to replace it, you decide to rebuild it using scrap parts.
Well, that’s exactly what YouTuber Baked Beans Garage recently decided to do. The YouTuber had a broken Mazda RX-7, but the original rotary engine had zero compression and wasn’t fit for purpose. Yet that didn’t stop him from trying to get the car back on the road.
Rather than get his hands on a rebuilt 12A engine, he decided the best thing to do was to go through scrap parts and make an engine out of those. “For many years now I have had several engines worth of subpar and damaged parts laying around,” he said. “So now I’m just going to throw together some of the best ones and see how long it lasts.”
That isn’t the sort of challenge that everyone will find appealing. It is, of course, much easier to just buy an engine that has been rebuilt, or one that only requires minor work. But that isn’t how this YouTuber operates.
Building a Rotary Engine Is Not an Easy Task
Some have said building a rotary engine is like building a “Dorito machine sandwich.” This is because it involves stacking flat cast-iron plates with aluminum housings that encapsulate the triangular rotors, which do look a bit like a Dorito. So even without using scrap parts, this isn’t the easiest task in the world.
Using scrap parts was clearly never going to be easy. For example, an aluminum rotor housing he pulled from his scrap pile had a hole punched straight through a water jacket. Yet he decided to blast it with abrasive, fill the hole with high-heat epoxy putty, and hope it would let the engine retain its coolant. That is the budget level for this wild build.
Other problems included installing the apex seals that seal the ‘Dorito’ against the housing walls. The irons had suffered aggressive porting, meaning the seals could fall into the intake port and destroy the engine. So Baked Beans used super glue to stick them to the side of the housing. The YouTuber joked that it was a legitimate technique, and admitted it was likely to come loose as soon as the tension bolts were torqued on. With a scrapyard engine rebuilt, it was a nerve-racking moment when the YouTuber went to fire it up for the first time.
Did the Mazda RX-7 Actually Work?
“I predict flooded four times, clean and bake the spark plugs five times,” said the YouTuber before he tried to start the car for the first time. Yet it went far better than he ever could have imagined. He had to fiddle with the carburetors and get it screaming at 1,900rpm while at idle. But the Mazda did actually start. And it held well at idle, even if it was quite aggressive; the fact was that it was running.
His bodged epoxy repair even held despite the pressure. “I must say I’m amazed by how well it runs with this cheap, ill-fitted carb straight out of the box and the mystery timing,” said Baked Beans Garage.
While it was very much done on a budget and with the cheapest parts possible, you have to admit the YouTuber did a tremendous job. And it has revived a car that otherwise probably would have just sat in his garage, still getting dusty. Proof you don’t need to spend a fortune to get a Mazda RX-7 running again.