1. Worn or damaged piston rings: Piston rings seal the combustion chamber and help control oil consumption. Worn or damaged piston rings can cause a knocking noise as the piston moves up and down the cylinder.
2. Piston slap: Piston slap occurs when the piston has excessive clearance within the cylinder. This can cause a knocking noise as the piston rocks back and forth within the cylinder.
3. Connecting rod bearing wear: Connecting rod bearings are located between the connecting rod and the crankshaft. Worn or damaged connecting rod bearings can cause a knocking noise as the connecting rod moves up and down on the crankshaft.
4. Main bearing wear: Main bearings are located between the crankshaft and the engine block. Worn or damaged main bearings can cause a knocking noise as the crankshaft rotates within the engine block.
5. Valvetrain issues: Problems with the valvetrain, such as worn rocker arms or lifter, can also cause a knocking noise in a big block Chevy engine.
6. Spark knock: If you hear a knocking sound coming from the engine under load, but it goes away when the load is removed, it could be spark knock or pre-ignition.
To determine the exact cause of the knocking noise, it is recommended to have the engine diagnosed by a qualified mechanic.
