Cam phasers are specially designed, computer-controlled cam gears that automatically optimize camshaft timing based on the current engine RPM and are currently used in all 2008+ Chrysler 5.7-6.4L VVT (Variable Valve Timing), 2005+ Ford Modular 3V, 2011+ Ford 5.0L DOHC Modular 4V V8 Ti-VCT (Variable Cam Timing) and 2007+ GM Gen IV VVT engines. Engine oil is pressure-fed to the phasers through passageways in the cylinder heads and cams. The engine computers control solenoids that adjust this oil flow into and out of the phasers’ control chambers, creating the ability to retard the cams.
While this technology provides fuel efficiency and the ability to always be in the best position for maximum power, regardless of engine RPM, it does present some limitations when it comes to performance cams. With such a wide range of valve timing movement, there is very little piston to valve clearance, which limits you to small cam profiles with little overlap.
The COMP Cams Cam Phaser Limiter Kits for the Chrysler Hemi, Ford Modular 3V and GM Gen IV VVT engines restrict the range of cam timing movement (14° for Chrysler, 20° for Ford and 22° for GM), thus providing the necessary valve clearance for serious performance cams with tighter lobe separations - all while utilizing the benefits of VVT technology. The Cam Phaser Limiters for the 2011+ Ford 5.0L 4V Ti-VCT engine limit the cam phasing to 25 crank degrees (12.5 cam degrees) while the cam phaser locks for that same engine allow fully adjustable locking over the OEM phaser range (50°).
The resulting upper-RPM gains from using COMP Cams Cam Phaser Limiters or Locks are some of the largest we’ve ever seen from a camshaft swap without sacrificing any bottom end or mid-range performance.