We may receive a commission on purchases made from links. While browsing auto repair and maintenance tools at your local parts store, you've likely come across compression testers like the Orion Motor ...

With every passing day the Mule provides opportunities beyond our original expectations. Since the 467ci engine belongs to HPP editor Tom DeMauro, it is at our beck and call. This affords HPP the ...

A normal Wankel has a triangle rotor spinning in a peanut-shaped housing. Liquid Piston flips that; now the peanut rotor spins inside a triangle housing. That small change makes a big difference. The ...

The internal combustion engine, for all its mechanical sophistication, still runs on a 19th-century mechanical idea: pistons rising and falling, a crankshaft spinning, a steam-age architecture ...

The rotary engine was an unconventional design that delivered great power for its size. Here's what's good and bad about it.