THE author points out that certain specialized bearing materials, such as the cadmium alloys, together with mixtures of copper and lead, will do more work than tin-base babbitt, but they insist on doing it in their own way. His paper consists essentially of a technical explanation of the peculiarities and characteristics of the higher-capacity bearings made from these specialized materials.
Data are presented to show that increased bearing mileage is obtained by the use of thinner linings. On the other hand, it is emphasized that engines in which thin babbitt bearings are used must be well protected by efficient air cleaners and oil filters since these bearings are particularly susceptible to the abrasive action of foreign particles in the lubricating oil.
In a discussion of replacement bearings, the unfavorable effects of the following conditions are emphasized: worn and out-of-round crankpins and journals; bowed crankshaft retained in line by force; warped crankcase; out-of-round connecting-rod bores and main bearing saddle bores; dirt within the engine; bearing caps misplaced sidewise; and improper clearance.
In a section on lubrication, Mr. Willi shows that the addition of a centrally located internal annular oil groove will improve the load capacity of bearings with a high L/D ratio.
Considerable space is devoted to a discussion of copper-lead bearings which, the author believes, will come into increasing use. This section is concluded by 15 rules for the installation of copper-lead bearings.