Benz Contra Engine
It is worthwhile to study this engine. The
function of the engine has not changed fundamentally. Even the thus angulated crankshaft points - assuming a constant ignition - to a two-stroke engine. It is called at that time three-stroke engine. The 'Contra' implies not indicative of a boxer engine, but on in opposite directions working, adjacent pistons. Left the drive for ignition, right the flywheel. A camshaft is not to see, a further indication of the two-stroke engine. Do you want another one? Then look below at performance data and compare them with engines of similar construction period.
Now the differences. The engine has neither oil sump nor pressure circulation lubrication. Each lubrication point has its own glass container. And the cylinder walls, if one is looking exactly. In this example, the lubrication of the connecting rod bearings is probably only possible if there are oblique bores in the crankshaft from the main bearing.