The dial gauge would be set at zero when crank is in ,say,port side near bottom position and gauge reading would be taken at port horizontal, top centre, starboard horizontal and starboard side near bottom position. Say x p t s and y as per figure, but before taking each reading the turning gear should be reversed to unload the gear teeth, otherwise misleading reading may be obtained
Any engines still with spherical main bearing will have greater allowances for crankshaft misalignment than those without. Spherical bearing have been used when increased