Avariablevalve timingmechanism has been developed. Itsstructure, operatingprincipleandpracticaleffectson theengineandvehicle performances are also presented.
Silverado and Sierra will accomplish its new mileage pinnacle with a 5.3L EcoTec3 V-8 relying on direct injection, cylinder deactivation and variable-valve timing to achieve EPA estimates of 16 mpg in the city and 23 mpg on the highway with two-wheel drive, or 16 in the city and 22 on the highway with four-wheel drive.