When Honda first introduced VTEC engines, they had the word 'VTEC' molded onto the valve cover for all VTEC variations. Because of this, it becomes very easy to determine if a particular engine is VTEC or not. However, with the latest generation of Civics, Honda has started to have VTEC engines with plain valve covers, often with only the word 'HONDA' molded on top. Owners of models with these engines sometimes get into unwarranted stress wondering if their engine is actually VTEC or not !
One of the most dependable way to identify if an engine is VTEC or not is to take off the valve cover and to take a look at the camshaft-rocker arms mechanism. Using this method, one can identify the exact VTEC implementation being used; SOHC-VTEC, VTEC-E, 3-stage VTEC, and etc.
However, it is also possible to identify a VTEC engine just by looking at the engine bay only. The method is to locate the VTEC hydraulic actuator switch that will be located besides the valve cover.
The VTEC hydraulic switch is a light-grey coloured cylinder attached to the head assembly. On DOHC VTEC engines, the VTEC actuator will be located near to the distributor. The picture on the left shows the VTEC switch on a B16B engine. The B16B engine is chosen specially because of its red valve cover which gives a very clear picture of the switch's location.
On SOHC VTEC engines though, the switch's location can be different. Typically it will be on the intake side of the engine, located above the intake manifold runners.
Below on the right is the D15B SOHC 3-stage VTEC engine used on JDM EK3 Civic VTi and Civic Ferio Vi. It is also used on the Civic VTi sedan in the Singapore market. This engine comes with a plain metal valve cover with no VTEC wordings or even cover paint !
When my mechanic first saw the engine, he quickly expressed doubts that it's VTEC. However, having many years of experience servicing JDM Hondas, after a quick look around the engine bay, the dual VTEC actuators caught his eye. Now he expresses surprise at a VTEC engine actually having two actuators ! (In the 3-stage VTEC implementation, one is used for stage-1 to stage-2 while the other for stage-2 to stage-3)