Crankshaft: Testing and Inspection

TOOL REQUIRED
- J 26900-1 Outside Micrometer
- J 8001 Dial Indicator Set
- J 26900-13 Magnetic Base


MEASURE (CRANK PIN)
1. Crank pin for out-of-round or taper with a Outside Micrometer. If crank pin is damaged, or out of round or taper exceeds limit of 0.01 mm (0.0004 inch), replace the crankshaft or regrind the crank pin to undersize and use undersize bearing.





2. Inspect rod bearing shells for signs of pitting, burns or flaking and observe the contact patter. Bearing shells found to be defective must be replaced. Two kinds of rod bearings are available standard size bearings and 0.25 mm (0.001 inch) undersized bearings. To distinguish them, the 0.25 mm (0.001 inch) undersize bearing has the stamped number US025 on its backside but the standard size has no marking.





RUNOUT
Using a Dial Indicator Set with a Magnetic Base, measure the runout at the center journal. Rotate the crankshaft slowly. If the runout exceeds the limit of 0.06 mm (0.0023 inch). replace the crankshaft.





END PLAY
Measure the end play With a crankshaft set in the cylinder block and with the thrust bearings fitted and connecting. rod caps installs, Use a Dial Indicator Set with a Magnetic Base to read the displacement in axial (thrust) direction of the crankshaft. Standard thrust play is 0.11 to 0.31 mm (0.0044 to 0.0122 inch). The limit on thrust play is 0.38 mm (0.0149 inch).





OUT-OF-ROUND AND TAPER (UNEVEN WEAR) OF JOURNALS
An unevenly worn crankshaft journal shows up as a difference in diameter at a cross section or along its length (or both). The difference, if any, is to be determined from readings using a Outside Micrometer. If any of the journals is badly damaged or if the difference exceeds the limit of 0.01 mm (0.0004 inch), regrind or replace the crankshaft.