In operation this means the relevant rocker arm will not be activated causing the engine to effectively work in 12-valve mode. This promotes a swirl action during the intake cycle. VTEC is used to activate the inactive valve, making the engine work in 16-valve mode in more demanding and higher rpm conditions.
LS/VTEC's are notorious for vacuum, oil, and coolant leaks,if the assembly and machine shop prepping of the head and block aren't done correctly. This re-emphasises the importance of selecting an experienced engine builder/machine shop that has put many together successfully before (proven track record of building them and they last for more Actual danger: Engaging VTEC below 2000rpm or above 6500 can damage the engine. Below 2000rpm (except on economy VTEC engines) the oil pump cannot supply enough oil pressure and it will damage the moving parts. Above 6500 or so the unlocked rocker arm can damage the valve spring retainers. Hraid750 • 5 yr. ago. Manufacturers usually guess how the engine will be used, and will then tune the valve timing to that speed. For instance, a sedan would probably run the most efficiently at medium engine speeds, while a sports car might run more efficiently at a higher RPM. VVT allows the best of both worlds by adjusting the cam to match the engine revolutions. Undoubtedly, VTEC and i-VTEC engines of the early 2000s hold a special place in our hearts. Those were some of the best Honda engines to build, specifically the B16, K20, D16Y8, K24, and D16Z6 engines. Not only do these motors showcase excellent reliability, but they also offer impressive performance at an affordable price. . 107 319 288 20 354 135 182 187 133