REMOVAL & INSTALLATION
The valve springs in these engines can be removed without removing the camshaft, while the cylinder head is in place. Follow the Valves Removal and Installation procedure if the head has already been removed.
- Remove the rocker cover. Set the cylinder on which you will be working to TDC on the compression stroke.
- Remove the rocker shaft assembly.
- Remove one spark plug on whichever cylinder you are working.
- Install an air hose adaptor into the spark plug hole and apply about 71 psi of pressure into the cylinder. This will hole the valves in place, preventing them from dropping into the cylinder when the springs are removed.
- Install a valve spring compressing tool similar to the one illustrated and remove the valve spring and valve steam seal. Use care not to lose the keepers.
Always install new oil seals during reassembly.
- Reassemble the valve and components. Making sure the air pressure in the cylinder is at 71 psi while the springs are being installed.
- Remove air adaptor and install the spark plug.
- Install the rocker shaft and rocker cover with a new gasket.
The camshafts in these engines must be removed in order to remove the valve springs. Follow the Camshaft Removal and Installation procedure, then follow the valve spring removal procedure listed above for the Z-series engines. If you are removing the valve springs with the cylinder head already removed from the engine, follow the procedure under Valves Removal and Installation.
HEIGHT & PRESSURE CHECK
- Place the valve spring on a flat, clean surface next to a square.
- Measure the height of the spring, and rotate it against the edge of the square to measure distortion (out-of-roundness). If spring height varies between springs by more than 1.5mm or if the distortion exceeds 1.5mm, replace the spring(s) in question. Outer valve spring squareness should not exceed 2.2mm; inner spring squareness should not exceed 1.9mm.
A valve spring tester is needed to test spring test pressure, so the valve springs usually must be taken to a machinist or engine specialist for this test. Compare the tested pressure with the pressures listed in the Valve Specifications chart in this section.