Crank and camshafts
In today's car engines hydro-dynamic bearings are almost ubiquitous. However it was not always so. In the 1920's and 30's rolling element bearings were the preferred technology to support crankshafts and for conrod bearings. Today rolling element bearings are usually only found in two stroke engines.
For the ultimate in friction reduction, especially at high rotational speeds, rolling element bearings do offer a direct advantage over hydro-dynamic bearings. Based on the design constraints these bearings can have solid or split rings and cages. This technology can also be applied to balancing shafts for further friction gains.