Project STurdteen: Building the SR20DET Engine

Then the head studs are tightened. SR20’s often have head sealing problems and the high strength studs with the improved head gasket will help.

Next, the correct valve shims are set to make sure the rocker arms sit straight.  This step is often neglected by people when working on SR’s. This makes the rocker arms sit at an angle to the cam lobe which increases wear and can cause the rocker to skid off the valves at high rpm. On the SR, one shim is a guide shim with a groove that holds the rocker arm in place. The other shim is select fit and is used to keep the rocker arm level.  Nissan makes this shim in many thicknesses so you can find the right one.

First, the hydraulic lash adjusters and rocker arms must be installed. The hydraulic lash adjusters are keep submerged in oil so they won’t get air in them.

A dial indicator whose rod is welded to the shell of an old lash adjuster is used to determine how thick of a shim is needed. The height of the top of the guide shim groove is measured and subtracted from the height of the valve tip.  The difference is the thickness of shim needed.

Here is a new select fit shim in place.


  1. For competition engines, I prefer not to use them because they are torque to yield and they stretch and take a set. They can only be reused maybe once and it’s a good idea to change them every time on a serious engine.

  2. for the mains, did you guys use arp’s torque spec or something else? I always thought it was a bit high

  3. Are you modifying the upper oil pan to clear the windage tray or did you find/make a spacer? the jet nuts on my tray touch the upper pan and require me to mod my pan.

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