LO 7-10 Outline techniques for connecting rod inspection and service
1. Connecting Rod Inspection and Service
1.1. Crack Detection
LO 7-10: Outline techniques for connecting rod inspection and service. |
Crack Detection
Connecting rods may be checked for cracks by using dye penetrant or magnetic particle detection. Stresses encountered during operation can lead to stress risers opening and a catastrophic engine failure. Machine shops can also check connecting rod bores for roundness and wear. Worn bushings in the small end can be replaced.
| Technicians Tip | ||
| The small clearance volume in diesel engines makes the engine vulnerable to hydrostatic locks. This occurs when liquids such as oil, coolant, or fuel enter the cylinder during servicing or through leaking head gaskets or water ingestion through the intake or porous cylinder walls. A bent connecting rod or locked engine will be the result of hydrostatic locks. In severe situations, cranking the engine can result in broken cylinder walls and bent valves. If a hydrostatic lock is suspected, barring the engine over in the opposite direction of rotation will usually allow the engine to rotate 360 degrees. During normal rotation, the engine will stop during the compression stroke of the cylinder that contains the liquid. Liquids can be vacuumed through injector nozzle openings in the cylinder head. Slightly holding an exhaust valve open while barring the engine over will also clear a lock. |
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