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The paper describes the development of cast iron crankshafts in austempered ductile iron (ADI). A ‘clean sheet’ approach was made covering basic alloy development, fillet rolling and fatigue properties, in order to come up with an alloy with the optimum properties for the application. The effects of variation in the alloying levels, as might be expected in mass production batches, were also studied. Full size crankshafts were manufactured and fatigue information was generated. Finally, ADI crankshafts were fitted into engines where noise and vibration measurements were undertaken followed by engine durability testing. This latter, most important, phase of the project was less successful and some engine failures occurred. These failures are also discussed. The work has highlighted some very worthwhile information on ADI as an engine crankshaft material and the paper indicates areas where of additional work is still required.

The paper describes the earlier research on cam and cam-follower materials carried out by MIRA using a specially developed, test machine. A table summarising the results of this earlier work is given. The use of the same test machine to assess the performance of lubricants when used in conjunction with standard components is also mentioned. The main part of the paper describes more recent work involving certain new processes and two ceramic materials as applied to cams or cam-followers. The results indicated that some of these processes or materials, particularly silicon nitride ceramic, can perform well in the cam and cam-follower situation. The results, particularly those for the very hard materials, were found to be influenced by surface finish, whilst the type of lubricant was found to affect the performance of chilled cast iron cams running against the ceramic materials.