DAYCO TIMING BELT KIT TO SUIT MAZDA E2500 SK SY WL DIESEL 2.5L I4Dayco Timing Belt Kit; Accurate Timing and System Reliability A timing belt kit is designed to service the complete timing drive system rather than replacing the belt alone. Components such as tensioners, idler pulleys and seals experience wear over time, and if left unchanged, can compromise the performance and service life of a newly fitted belt. Dayco timing belt kits are engineered to restore correct operating conditions across the entire timing