Earlier I was reading about the Rootes TS3 (two-stroke 3 cylinder) engine, used in Commer trucks.
The engine has three cylinders situated above and across the plane of the crankshaft. Each cylinder contains two pistons with the crown facing inwards. On each side the pistons are linked to the crankshaft via a short connecting rod, a substantial rocker arm and a secondary connecting rod. Unlike a petrol engine, a two stroke diesel cannot use crankcase pressure to boost the air supply, because it would tend to combust any oil that was entrapped in the air. A Roots blower is situated on the front of the engine and supplies the combustion air. The total displacement is only 3.25 litres, but the engine develops 90 B.H.P. Contemporary four stroke engines produced this kind of power from 8 litres.
http://www.sa.hillman.org.au/TS3.htm
Best of all is the sound it makes - raspy and gruff, but in a good way: - http://www.youtube.com/watch?v=e0sLp7wvq60
What are some other unconventional engines that made it into cars/trucks/boats? The Wankel is an obvious one, but they're relatively common and still in production.


