The Heart of a Record Breaker III: Completing the VVL Head Swap and Engine Assembly


Remember the steel braided line we routed from the oil pump to the VVL solenoid?  That line delivers oil to the VVL solenoid and at a certain RPM, the solenoid opens a passageway.  In doing so, oil is sent down the length of a long, hollow rocker arm shaft, which spans the cylinder head.  Each rocker arm is mounted to this rocker shaft and oil is delivered to it via the hole inside the bore of the rocker arm.  

Oil pressure then acts on the backside of a VVL activation pin which drives it outwards.  When the pin moves outwards, it pivots a foot which locks in place underneath the high lobe portion of the rocker arm. 
Here you can see the SR20VE VVL rocker arm in both the unlocked (left) and locked (right) position. 

In the locked position, the middle journal of the rocker arm engages the larger cam lobe that is located in between the two small cam lobes.  The large cam lobe profile results in increased valve lift.  Got it? Now back to the build…

After consulting with Clark Steppler of Jim Wolf Technology, he advised that we should figure out a way to lock the exhaust rockers.  The hypothesis was that by locking the exhaust rocker on the big cam lobe we would increase overlap and lift, which would help exhaust flow and ultimately help us spool our herculean Borg Warner EFR 8374 faster.  

In addition to controlling boost, our Turbosmart, E-boost Street also featured an adjustable RPM switch.

If we ran the dual solenoid set up which comes on the early model VVL engines, locking out the exhaust rocker would be as easy as using the RPM switching feature of our Turbosmart E-boost Street boost controller.   Or, we could have this switching incorporated into our Jim Wolf Technology ECU.

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