Having proved our compact radial engine on the dyno, the next step was to put it in a vehicle. We wanted its first run to be memorable and thanks to ex-RAAF and Cathay Pacific Captain Jim Twiss and his beautiful 1940 Boeing 75 PT-17 we certainly won’t forget it in a hurry!

The Radial Motion engine is a direct bolt-in swap for Volkswagen flat-four applications. In this video we install the compact radial engine into a VW-based trike. It is just as simple to fit into the Beetle, Kombi and other VW vehicles, as well as Porsche 356 and Porsche 912/914. Other vehicle platforms are also supported – contact us for details.

The Radial Motion engine has three gear driven camshafts. By using pushrods, we were able to offset the rockers and valves to one side to allow more ground clearance on the lower left head. The lower right head is rotated 180° to allow the same ground clearance on that side.

This arrangement has other benefits too, including simplicity of assembly and service, reliability and availability of off the shelf parts.

Watch as one of the heads for the Radial Motion compact radial engine emerges from the mould.

The Radial Motion engine has a common crank journal and easily available conrods, rather than the traditional system of master crank/slave rods used in aviation in the early years. This means that the Radial Motion engine occupies the same footprint as equivalent flat four engines and that ground clearance is not an issue for road or off-road use.

Triple carb test.
First test of our carburettor setup worked a treat! We literally unboxed the carbs, fitted them and started the engine – it sounds great and seems very responsive, which is a great starting point.
Next step – get it tuned on the dyno.

See aspects of the design, manufacture, build and dyno testing of the second generation Radial Motion compact radial engine.

This is the first round of dyno testing using fuel injection with a plenum chamber. Carbs and ITBs to follow ...

The 120° layout of the Radial Motion compact radial engine is superbly balanced without the need for balance shafts.

Check out the coin balancing on the oil filter at idle.

Smooth.