EPI reveals more powerful, lighter, cheaper engine to replace O-200

EPI engine

American engine specialists EPI Inc has released details of a new clean sheet design engine it is developing for an unnamed client – believed to be Vashon Aircraft.

The engine is described as a modern, air-cooled four-cylinder aircraft engine that produces 126hp, weighs 186 lb (84kg) and is a direct replacement for a Continental O-200 engine, costing less than half the price.

EPI has released a video of the engine’s first start with John Torode, founder of Vashon Aircraft and Dynon Avionics, clearly seen (wearing brown jumper).

Torode promotes the Vashon Ranger light sport aircraft as an ‘all-American’ product and is known to be keen to have a more modern power unit than the existing 100hp O-200.


The new engine has been designed and built by EPI Inc for a ‘client company’ that owns all materials and production and intellectual property rights. FLYER has contacted Vashon Aircraft for a comment.

Vashon Ranger

Is this the aircraft that the new EPI engine is destined for? The Vashon Ranger. Photo: Vashon Aircraft

EPI says, “The engine is a 200 cubic inch, horizontally-opposed 4-cylinder engine which is a bolt-in replacement for the O-200 (although a different motor mount will be required to clear the accessories on the back of the engine).

“It (as of current dynamometer testing) produces 126hp at 2700rpm, corrected to accepted sea-level, standard conditions (59°F ambient temperature and 29.92 in-hg ambient pressure).

“The prototype engines weigh 191 pounds but there is a weight-loss programme underway which looks as if it will reduce the weight by an additional 5 pounds with no effect on reliability or power output.”

EPI cylinder

A feature of the new EPI engine is monolithic machined cylinders. Photo and video: EPI Inc

Features of the new engine include:

  • Monolithic aluminum cylinders
  • Eight cylinder hold-down studs
  • Electronic ignition coil packs
  • High strength-and-stiffness crankcase cast from a premium heat-treated alloy
  • Optimised multi-gallery lubrication system with full-flow spin-on filter, oil cooler ports, and integrated oil thermostat
  • Custom-designed high-strength, high-stiffness crankshaft that has an integrated 4-inch propeller extension, allowing better cowling aerodynamics
  • High-strength H-beam connecting rods
  • Pistons forged from a high-strength aluminum alloy (developed by Rolls-Royce for aircraft engines)
  • Electronically-controlled fuel injection and ignition, with optimised maps.





  • LT says:

    I saw the same video and thought there were a couple of familiar faces in the video (at least two Vashon guys in the background, one being Mr. Torode). Thanks for confirming my hunch. Did they ever reply? Any follow up news?

    This would be a home run for Vashon if it comes to fruition – great upgrade to their R7 or another upgraded model, but also for legacy small aircraft owners looking to upgrade. I’d love to see a bolt-on O-200 replacement engine with a bit more power to it – depending on the price, it might be better than doing an overhaul. I’m curious if its a modern engine, would it be fuel injected and have some kind of FADEC or computerized engine control?

    Regardless, I hope the project is on track and wish them best of luck and market forces.

  • Gary Van Meter says:

    From the way I read it you’d have to modify the engine mount to clear the accessories. And it could not be used in a certified aircraft as this engine won’t be certified. But it would sure give Rotax some good competition with more horsepower, much lower cost, and a simpler installation. I sure hope they build it and can keep the cost low. If so, they have a winner!! I talked to the design engineer, who thought with different cylinders it could handle turbocharging and make about 200 hp. But I doubt we’ll see that happen.

    • Jay says:

      I’ve been a longtime reader of the tech articles on EPI’s website. They are informative, and dispell many myths floating around the internet. The reference library is the real source of information, of course. And we’ll documented and referenced.

      That being said, a clean sheet engine design is an overwhelming task that requires substantial investments in time, money, engineering, and most importantly, durability testing.

      The idea that one engineer can clean sheet an aero engine that will fly off the drawing board and beat what is arguably the most refined and developed lightweight air cooled aero engine in history, is a far stretch for anyones imagination.

      Though it’s loosely based on the small Continental line, and borrows many proven concepts, and utilizes modern materials and production machines, it’s all new and therefore every aspect must be tested and tried.

      It takes a significant amount of money to build several one-off engines, and run them to TBO and way beyon for durability testing. At 8gph it would take 16,000 gallons of avgas to reach 2,000TBO, and you can’t sell an engine to the public unless you’ve done that to several new, and overhauled motors. That’s on a Dyno, with technitions and engineers on standby reviewing the data and implementing solutions. It’s a multi-million dollar, half-decade process to do it right; designing even a simple aero engine. It’s no small undertaking, though I’m happy to see people attempt it.

      So don’t hold your breath for a consumer-ready product for many years to come.

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