Thread: Whats this??

The small part marked in blue,,
by the look of the chain it is some form of pulley tensioner,
or,
can it vary the valve timings from there?



and yes,, its of a D3 V8,,
(yes Santa,, Ive been good)

Variable Cam Phasing: The AJ-V8 employs variable cam phasing (VCP) to reap the midrange benefits of advanced cam timing and the high-speed advantage of retarded valve closing, delivering no less than 80 percent of peak torque between 1400 and 6400 rpm. The timing shift involves only the opening and closing points of the intake valves; it does not change the length of the open period (duration) or the height to which the valve is opened (lift).
The benefit to the driver comes in crisp throttle response, with abundant torque at low speeds and outstanding power as the engine speed climbs toward the top of the tachometer.

The mechanical movement of the intake camshafts is performed by a hydraulic actuator controlled by the engine management system.

At very low engine loads, as well as very low and high engine speeds, the intake camshafts are in the retarded position. In this mode, the valve overlap period (when both the intake and exhaust valves are open) is a minimal five degrees of crankshaft rotation, which provides a smooth, stable idle.

The intake camshafts move to the advanced position when the engine operates at low-to-midrange speeds or at higher loads. In this position, overlap increases, allowing some of the exhaust to flow into the cylinder with the fresh mixture, benefiting emissions control. The exhaust-laden mixture burns cooler, reducing nitrogen oxides, and reburning the exhaust lowers hydrocarbons.

For reliability, the camshafts are driven by zero-maintenance, single-row chains.

This is from a US website
regards Philip A