What Causes an Engine to Experience Piston-to-Valve Contact?

[LaJack]

Piston-to-valve contact occurs when excessive connecting rod clearance results in an elongated connecting rod. During engine operation, this causes the piston to strike the cylinder head, known as piston-to-valve contact. Additional Information: 1. When there's an issue with the connection between the piston and connecting rod, such as excessive clearance, it can cause the piston to deviate from its normal travel path and directly impact the cylinder head. 2. Timing chain or belt detachment, or crankshaft pin fracture, may also lead to piston-to-valve contact (commonly referred to as 'timing jump'). This happens when the timing belt has been in service too long, exceeded its lifespan, or when the timing belt tensioner has failed. The resulting looseness between the timing belt and sprocket creates clearance that can cause piston-to-valve contact.