Checking Valve Spring Installed Height

Important: 

• If the valves have been refaced and/or the valve seats ground, or insufficient valve spring force is believed to be the cause of poor engine performance, it may be necessary to check the valve spring installed heights prior to final assembly.
• Ensure the valve, keys, and spring cap are correctly seated with one another and the valve stem.

1. Install the valve rotator (3), the valve (4), the valve spring cap (1) and the valve stem keys (5) into the cylinder head.
2. Using a snap gauge (2) or inside micrometer, measure the distance from the top of the valve rotator to the bottom of the valve spring cap.
   • If the measured installed height is less than 41.61 mm (1.64 in) no shims are required.
   • If the measured installed height is between 41.61-42.37 mm (1.64-1.67 in), install a maximum of one 0.76 mm (0.030 in) thick valve spring shim.
3. Install a valve spring seat shim if the valve spring installed height measurement is above the specification. Install the valve spring seat shim on top of the valve spring seat surface of the spring seat/seal unit.
4. Recheck the valve spring installed height, replace the cylinder head if the valve spring installed height cannot be obtained.