H engine

The name was also applied to engines of the same basic layout, but rotated through 90 degrees—most famously the Napier Sabre series.

The British Racing Motors (BRM) H-16 Formula One engine won the 1966 US Grand Prix in a Lotus 43 driven by Jim Clark.

As a racing-car engine it was hampered by a high center of gravity, and it was heavy and complex, with gear-driven twin overhead cams for each of four cylinder heads, two gear-coupled crankshafts, and mechanical fuel injection.

German firm Konig, who specialised in racing outboard motors,[6] built a few 1000cc H-8s in the 1970s, which were basically two of their VC500 flat fours mounted one above the other, with the direction of rotation reversed on one of them.

Each half of the engine was a water cooled 2-stroke with rotating disc valve driven by a toothed belt via two 45/90 degree pulleys, plus two siamesed expansion chamber exhausts, fed by two single choke carbs.