Top Dead Center

“Top Dead Center” (TDC) refers to the position of a piston in an internal combustion engine at its highest point of travel within the cylinder. This position marks the end of both the compression stroke and the exhaust stroke in a four-stroke engine cycle. At TDC, the piston is at its furthest point towards the cylinder head, and it’s typically when the spark plug ignites the compressed air-fuel mixture in the combustion chamber to initiate the power stroke. TDC is a crucial reference point for engine timing and tuning adjustments.

See

• After top dead center
• Before top dead center