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



On an SR20VE and SR16VE, two long rocker arm shafts secure all of the rockers arms in place.  This is a part of what makes these heads more suitable for high RPM use. 

Now that my hand is peeled from my face, I’ll elaborate further on what makes the SR20VE head better than that of a traditional SR20DET cylinder head.  The SR20DET has the pesky tendency for its rocker arms to fly off at high RPM.  On the SR20DE and SR20DET engines, the rocker arms are basically free floating only being wedged in between the camshaft, hydraulic lash adjuster and valve tip.  This is why they fly off at high RPMs and cause all sorts of ruckus.  The VVL cylinder head’s rocker arms are solidly mounted to a rocker shaft, making it impossible for them to fly off. 


As a side note, those aftermarket thin metal rocker arm stoppers that are made for SR20DET engines are utterly useless.  I’ve found that they don’t help prevent the rocker arms from flying off and actually cause more damage to the rocker arms when they do decide to fly off.  Instead of just letting the rocker arm fly off, they wedge the rocker arm in place causing them to break.  So now, you’re not only searching your engine for shims but you’re also in need of new rocker arms.

The intake and exhuast valve pockets had ample clearance, .120 and .080″ respectively.

Before Nick Hunter could wrap up the assembly for good, he had to first verify piston to valve clearance. This meant assembling the head completely and installing it on to the block only to disassemble it again. It’s a small price to pay to verify that the valve pockets in our JE pistons had enough valve clearance for us to cope with the advanced and retarded camshaft timing settings.


After checking piston to valve clearance, Nick installed an OEM 20V head gasket.  Unlike the older variants of the SR20, the SR20VE 20V gasket is constructed from multi-layered steel.  The 20V gasket features an embossed fire ring around the bore which is coated in a rubber-like viton to improve micro sealing around the combustion chambers.  A similar material is used around the cooling passages to aid in sealing there as well.    

Before installing the SR20VE 20V cylinder head for the last time, Nick Hunter removed all of the shims. Without this step, the valve shims would have become dislodged in the nether regions of the cylinder head surely resulting in a profanity filled rant.  


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