Back the wheel out, and measure the journal with a micrometer to determine how much material must be
removed to attain the proper size. Set the feed indicator for this amount.
While keeping a careful check on the journal size, slowly feed the wheel in until the correct undersize has
been reached, and set the index on the feed indicator to 0. Let the grinding wheel dwell at this point until
spark-out occurs; this will improve surface finish and help prevent grinder bum damage.
Back the wheel out and traverse over to the other side of the journal. Feed the wheel in until it just touches
the journal, and traverse over into the fillet area.
Feed the wheel in slowly until the feed indicator reaches 0, and spark-out has occurred. Back the wheel
out and check the journal.
When checked with an outside micrometer, the journal shall be the correct undersize, and have no
detectable step at the point of wheel overlap.
Alternate each main bearing journal as to which cut it made first If, on the first bearing journal,
the right side was full width cut, then on the next journal make the full width cut on the left
side. The results in a more even breakdown of the grinding wheel and aids in producing a
good surface finish on the reground journals.
Grind all other main bearing journals in accordance with steps (30) through (35) above.
The crankshaft thrust flange surfaces may be ground to an undersize of 0.010 inch (0.25 mm)
or 0.020 inch (0.51 mm). Oversize thrust bearings are available for use with crankshafts which
have had the thrust surfaces ground to these sizes. Grind each of the thrust surfaces to dean
up grooving, abrasions, nicks, and wear. The front and rear thrust surfaces need not be
ground to the same standard size, but the crankshaft must be stamped to show the thrust
surface size. For uniform loading of the thrust bearing during engine operation, it is
necessary that the thrust surface be ground square with the centerline of the crankshaft
within 0.002 inch (0.05 mm) TIR. Squareness of the thrust surfaces should be checked with a
dial indicator indexed near the outer edge of the thrust surface. If there is no damage (nicks,
grooves, abrasion) to the thrust surface, up to 0.005 inch (0.13 mm) wear may be tolerated and
considered as standard. If there is damage, then up to 0.005 inch (0.13 mm) may be removed
and the thrust surface may be considered standard. If more than 0.005 inch (0.13 mm) wear is
present or if more than 0.005 inch (0.13 mm) must be removed to properly dean up the thrust
surface, then it must be ground to accept oversize bearings of 0.010 inch (0.25 mm) or 0.020
inch (0.51 mm). A maximum of 0.020 inch (0.51 mm) on each thrust surface may be removed
(37) Make a visual inspection of the thrust flange, and determine to what extent grinding must be done to dean up any
wear or damage.
If the thrust flange is within wear limits, and scoring is not over 0.003 inch (0.08 mm) deep,
restore the surfaces by polishing, or a very light grinding.
Determine the standard oversize that is needed on the front or rear thrust surface.
When grinding, do not traverse the grinding wheel Into the thrust surface. This will cause the
side of the grinding wheel to break down, and may cause Injury to personnel, damage to
equipment, or grinder bum.
Feed the wheel almost to the journal and then traverse it over until it just touches the thrust surface to be
ground. Then, back the wheel away from the journal until it dears the thrust surface.
Traverse the wheel over to make the desired cut. Leave approximately 0.001 to 0.002 inch (0.030 to 0.050
mm) for a final cut. For example: if 0.009 inch (0.23 mm) must be removed from the surface, traverse the
wheel over 0.007 inch (0.18 mm) and feed in slowly to make the cut. Back the wheel out and traverse
over 0.002 inch (0.05 mm) to make the final cut. Feed the wheel in slowly when making the final cut, and
allow the wheel to spark-out at the journal.