Jalopnik’s Dream Engine Swap: A Mazda Rotary in a Porsche 912E

Ideas Beyond the Factory

Car enthusiasts often dream up builds and debate how well the combinations might work, regardless of whether they have the time, money, space or skills to complete them. Sharing those ideas can inspire someone else to begin a project or rethink an existing plan.

Manufacturers do not always pair their strongest engines with the chassis enthusiasts would choose. Home mechanics and backyard engineers can make different combinations possible, including engines from other manufacturers or motorcycle engines. The writer invites readers to share their ideas in the comments, with some responses to be recapped the following week.

A Troubled Triumph Project

The writer’s first fun car was a 1976 Triumph TR-7 fitted with a Buick 231 V6. The installation was poor, the car had serious rust, and the engine was more worn than the writer had been told.

After buying it, the writer removed and rebuilt the engine during a winter of college nights and weekends. The car was eventually scrapped, but the engine remains on a stand. The experience helped shape the writer’s enthusiasm for cars and engine swaps.

A Rotary for the Porsche

The writer’s longest-owned car, a Porsche 912E, has had ignition problems for about three years. Its original 2-liter flat four makes about 88 horsepower; after a 2019 rebuild, it is in the 110-hp range. The writer would like more power and higher revs, but considers a later 911 flat-six too conventional.

Instead, the writer is considering a Mazda 13B rotary. A carbureted Formula Mazda 13B produces about 180 hp, while a modern Renesis makes just over 200. The writer hopes for at least 150 horsepower in the Porsche.

A rotary would be an unusual but established choice for a Porsche chassis, the writer says. It could be lighter and more powerful, rev beyond 4,500 rpm and make a satisfying sound. The writer may start collecting parts over the winter.