Product Code:SAE J542 Title:Starting Motor Mountings Issuing Committee:Electrical Systems Group Scope:The purpose of this SAE Recommended Practice is to provide standardized dimensions for mounting starting motors. It is recommended that a full register diameter having a minimum depth of 2.54 mm (0.100 in) be provided in the flywheel housing to insure proper control of gear center distance and clearance between pitch diameters. The clearance between the starting motor pilot diameter and the register diameter in the flywheel housing should be 0.03 mm (0.001 in) minimum to 0.25 mm (0.010 in) maximum.