The machining process of enlarging the internal diameter of an engine block cylinder using a boring bar and hone. This is done to repair scored cylinder walls, restore perfect roundness, or increase the overall displacement of the engine for more power. It requires fitting new, oversized pistons and rings.
Heard on the job
We had to overbore the block by 30 thousandths to clean up the rust pitting in cylinder three.
Also heard as
- bore out