The big end is the lower, larger portion of an engine's connecting rod that wraps around the crankshaft journal. It houses the rod bearings and is secured by a bolted cap. Because it handles the violent rotational forces of the crankshaft, a lubrication failure here usually results in catastrophic engine damage, commonly known as throwing a rod.
Heard on the job
We found copper shavings in the oil pan, so the big end bearings are definitely wiped out.
Do not mix it up with
- Bottom-end: The big end is a specific part of the connecting rod, while the bottom end refers to the entire lower assembly of the engine including the block, crank, and rods.