Attach a dial indicator to the crankshaft. The dial indicator can be mounted by any method that holds the extension
bar of the indicator rigid so it does not sag. If the bar sags or the indicator slips, the readings obtained will not be
accurate.
Position the indicator in the 6 o’clock position and zero the gauge.
Slowly rotate the crankshaft. Record the readings obtained at the 9 o’clock, 12 o’clock, and 3 o’clock positions
as [a], [b], and [c] in the concentricity work sheet. Recheck zero at the 6 o’clock position.
The values for [a], [b], and [c] could be positive or negative. Refer to the accompanying figure to determine the
correct sign when recording these values.
Rotate the crankshaft until the dial indicator is at the 12 o’clock position and zero the gauge.
Caution: do not force the crankshaft beyond the point where the bearing clearance has been removed. Do not
pry against the flywheel housing. These actions could cause false bearing clearance readings.
Using a pry bar, raise the rear of the crankshaft to its upper limit. Record the value as [d] in the concentricity work
sheet. This is the vertical bearing clearance adjustment and will always be positive.
Using the concentricity work sheet, determine the values for the ‘total vertical’ and ‘total horizontal’ values.
The ‘total horizontal’ is equal to the 9 o’clock reading, [a], minus the 3 o’clock reading, [c].
The ‘total vertical’ is equal to the 12 o’clock reading, [b], plus the bearing clearance, [d].
Using the work sheet and the numbers from the example, the ‘total horizontal’ value = 0.006” and the ‘total verti
cal’ value = 0.005”.
Mark the ‘total horizontal’ value o n the horizontal side of the chart and the ‘total vertical’ on the vertical side of the
chart.
Using a straight edge, find the intersection point of the ‘total horizontal’ and ‘total vertical’ values. The intersection point must fall within the shaded area for the flywheel housing concentricity to be with specification.
Using the ‘total horizontal’ and ‘total vertical’ values from the previous example, the intersection point falls within
the shaded area. Therefore, the flywheel housing concentricity is within specification.
If the intersection point falls outside the shaded area, the ring dowels must be removed and the housing repositioned.
NOTE: The ring dowels are not required to maintain concentricity of the housing; the clamping force of the capscrews holds the housing in pace.
After the ring dowels are discarded, install the flywheel housing on the engine.
To position the housing, tighten the capscrews enough to hold the flywheel housing in place, but loose enough to
enable small movement when struck lightly with a mallet.
Recheck the concentricity. When concentricity is within specification, torque the capscrews to the specified value.
