ASE A1 Engine RepairEngine Block AssemblyMedium
A technician is assembling an engine and notices that the connecting rod bearings show wear patterns indicating 'edge loading' or 'uneven wear' on one side. Which of the following is the MOST likely cause?
- AA bent connecting rod or misaligned connecting rod cap.
- BExcessive crankshaft end play.
- CContamination in the engine oil.
- DInsufficient oil pressure to the connecting rod journal.
Show answer & explanationAnswer & explanation
Correct answer: A. A bent connecting rod or misaligned connecting rod cap.
Edge loading or uneven wear on one side of a connecting rod bearing is a classic symptom of a bent connecting rod or a misaligned connecting rod cap, which causes the bearing to contact the journal unevenly.
Why the other options are wrong
- B. Excessive crankshaft end play primarily affects the thrust bearings, not the connecting rod bearings directly in this manner.
- C. Contamination in the oil would cause pitting, scoring, or embedding of particles across the bearing surface, not specific edge loading.
- D. Insufficient oil pressure would typically cause general wear or scoring across the entire bearing surface, not concentrated edge loading.
Connecting Rod Bearing Edge Loading
Edge loading is a wear pattern on a connecting rod bearing characterized by concentrated wear on one side, often due to part misalignment.
- Indicates a bent connecting rod or misaligned cap.
- Causes uneven pressure distribution on the bearing.
- Leads to premature bearing failure.
Memory trick: Wear on the edge? Check the rod's wedge!