Engine & Engine Overhaul

ENGINE MECHANICAL

Valve Springs

Fig. 1: Using a compressor to remove the valve spring-except 2.5L and 3.3L engines

The following procedure may be performed with the cylinder head on the cylinder block by using a chuck and a compressed air source to fill the cylinder with air. This will hold the valve closed and prevent it from dropping into the cylinder.

1. Remove the valve system and related components.
2. Remove the cylinder head.
3. Using a valve spring compressor, compress the valve spring and remove the valve spring key retainer.
4. Remove each valve spring assembly.

5. Lubricate the valve stems, and install the valves in the cylinder head as numbered.
6. Lubricate and position the seals (if used) and the valve springs.
7. Install the spring retainers, compress the springs, and insert the keys.
8. Tap the head of the valve lightly with a wooden hammer to seat the keys.
9. Install the cylinder head.
10. Install the valve system and related components.
11. Adjust the rocker arm clearance as required.

Fig. 2: Check the valve spring for squareness on a flat surface; a carpenter's square can be used

Place the spring on a flat surface next to a square. Measure the height of the spring, and rotate it against the edge of the square to measure distortion. If spring height varies (by comparison) by more than ¹/₁₆ in. (1.6mm) or if distortion exceeds ¹/₁₆ in. (1.6mm) replace the spring. In addition to evaluating the spring as above, test the spring pressure at the installed and compressed (installed height minus valve lift) height using a valve spring tester.

Measure the distance between the spring pad and the lower edge of the spring retainer, and compare to specifications. If the installed height is incorrect, add shim washers between the spring pad and the spring. Be sure only to use shims designed for this purpose

END OF SECTION