Actually, the four-stroke engine (almost) always features sliding bearings. If only it would be possible to insert roller bearings into a four cylinder in-line engine! It is a pity that one cannot provide the ease of the rotation through an Internet site. One would understand immediately how much friction power and thus energy is saved.

The figure shows half a roller bearing cage. They are inserted with accordingly prepared bearing like the half shells of the sliding bearing. The external half shell is inserted into the case with its rollers, without twisting. The large edge is striking. It is calculated to achieve a short distance to the crankshaft, so that the oil does not flow out in large quantities sideways out of the bearing. Also, the other lubricating points should be supplied with oil through inside borings.All together it (still) is not a project for large series, but the engine already managed quite a few test runs.

In the history of the car there have been four-stroke engines with pressure circulation lubrication and roller bearings, e.g., the Porsche 356 and the Citroen 2 CV, here, however, with completely factory-mounted bearing. Because undivided roller bearings can be mounted only if big-end bearings and crank webs can be separated and pressed together again in the same position. 06/07