The Newest Combustion Engine Is a Throwback Radial Triple

As the automotive propulsion industry shifts toward electrification, the last-of-breed combustion engines are a stultifyingly similar bunch, focused around the same CAD-optimized 500cc cylinder designs that produce 2.0-liter inline four-cylinders, 3.0-liter six-cylinders, and 4.0-liter V8s.

Fortunately, the engineers at Radial Motion haven’t gotten the memo, all the way down under in South Australia. They’ve provided us with an oddball three-cylinder engine in an aircraft-style radial configuration that has been adapted to automotive use.

This is appropriate because while the first planned application of the Radial Motion engine was for aircraft, the engine’s design relies on standard General Motors LS small block V8 engines for its internal architecture and Volkswagen Beetle dimensions for its flywheel and engine-to-transmission mounting points.

The limited-production Tarmac Touring Edition Meyers Manx, powered by the Radial Motion 3-cylinder radial engine. MEYERS MANX

The Radial Motion engine’s unusual dimensions and its bolt-on compatibility with the Volkswagen transaxle make it the perfect powerplant for a VW-based vehicle with little rear bodywork, so it is no surprise that the company has partnered with Meyers Manx to release versions of the iconic dune buggy that are powered by this unique three-cylinder engine.

Meyers Manx proposes to make a limited run of just six Tarmac Touring Edition versions of the dune buggy, finished in gunmetal metal flake paint. They don’t list a price, so apparently if you have to ask, you can’t afford it. For reference, a basic DIY kit to assemble your own Manx costs about $15,000 and Radial Motion sells the engines for $25,000.

Related:Meyers Manx 2.0 EV Modernizes the Classic Dune Buggy

The question is, ‘How much is it worth to avoid the disheartening sound of the VW Beetle engine that would otherwise power your Manx?’

“The unique sound of a radial engine is a rare experience today, often encountered only at airshows or from passing classic aircraft,” said Phillip Sarofim, Meyers Manx chairman. “By featuring the Radial Motion engine from Bespoke Engineering prominently in this series of Meyers Manx Remastered Buggies, we are preserving this historic engine format and allowing future generations to appreciate the power that once drove the world's great airplanes.”

The engine is a three-cylinder layout with the cylinders spaced at 120 degrees in a radial. Radial Motion employs a common crankpin for all three cylinders' rods rather than the traditional master and articulating rods. This is simpler and more compact and it allows the use of off-the-shelf GM connecting rods.

Another departure from radial engine convention is the use of a dedicated camshaft for each cylinder, rather than running all the cylinders off a central cam.

Related:World’s Most Powerful 3-Cylinder Engine Propels Toyota Gazoo Racing Yaris WRC

Valve actuation is by pushrods and rocker arms, with the hardware borrowed from the GM LS small block engine family. Because the radial’s two bottom cylinders have heads that are below the crankshaft, the company says it chose this configuration rather than overhead camshafts to minimize how low the engine hangs to avoid having it scrape on the ground.

Oil would collect in those inverted heads, so the Radial Motion engine has a dry sump oil system employing a dedicated scavenge pump to evacuate oil from each head in addition to the main pressure pump. There are individual oil squirters lubricating each of the three camshafts.

It is rated at 120 horsepower in base configuration, but the engine can be tuned to deliver as much as 240 naturally aspirated horsepower or 260 horsepower with forced induction. With its modular design, the three-cylinder modules can be stacked to produce 4.0-liter six-, nine-, and twelve-cylinder engines too. The original design employs a minimal water-cooling system, but air-cooled variants are available.

In addition to the Manx dune buggy, Radial Motion has demonstrated the radial engine installed in a VW Beetle, a VW bus, a Porsche 356, and even a motorcycle trike. The company says it will work with customers to develop an installation solution for other vehicles.

Related:The $60,000 Infiniti QX50 Has The World’s Most Advanced Combustion Engine

It is expensive and not well-suited to installation in many vehicles, but it is fun that Radial Motion is providing us with this unorthodox send-off of combustion engine technology. As the company explains on its website, “Radial Motion engines are all about individuality and fun. While mass transport moves to electric and hybrid, there is still room to make a little noise.”