Variable valve timing and lift, however, can alter timing and lift to the optimal settings for the engine speed and powerChecked 2026-08-12
Variable valve timing (VVT)
A system that changes when — and sometimes how far — the valves open, instead of one fixed setting.
Also called: VVT · VTEC · VVT-i · VANOS · variable valve lift
What it means
Definition
Older engines opened their valves at one fixed timing, chosen as a compromise across the rev range. The DOE describes what changed: variable valve timing and lift can alter timing and lift to the optimal settings for the engine speed and power. Manufacturers brand their versions differently — Honda's release describes VTEC as Variable Valve Timing and Lift Electronic Control, introduced in the late 1980s.
Why a buyer cares
What it changes
It is near-universal on modern engines, so seeing it in a spec sheet says nothing unusual. What is worth reading is a stored code naming a VVT or camshaft position actuator, which points at the timing control rather than the engine as a whole.
In practice
Where you meet it
On badges and spec sheets under a brand name, and in trouble codes naming a VVT or camshaft actuator or solenoid.
Two things that look alike
Not the same as
Cylinder deactivation switches cylinders off; variable valve timing changes when valves open on cylinders that are running.
Read next
Related terms
Where this comes from
Sources
Variable Valve Timing and Lift Electronic Control, or VTEC®, debuted in the late 1980s as a way to extract maximum horsepower and torque from smaller displacement engines without using turbocharging.Checked 2026-08-12
A research agent proposed a Honda sentence calling VTEC the first commercially successful such system; that sentence is not on the page and was replaced.