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 1.5mm or if distortion exceeds 1.5mm, 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. Spring pressure should be - 1 lb. of all other springs in either position.
VALVE & SPRING INSTALLATION
Be sure that all traces of lapping compound have been cleaned off before the valves are installed.
- Lubricate all of the valve stems with a light coating of engine oil, then install the valves into the proper ports/guides.
- If the umbrella-type valve seals are used, install them at this time. Be sure to use a seal protector to prevent damage to the seals as they are pushed over the valve keeper grooves. If O-ring seals are used, don't install them yet.
- Install the valve springs and the spring retainers (or rotators), and using the valve compressing tool, compress the springs.
- If umbrella-type seals are used, just install the valve keepers (white grease may be used to hold them in place) and release the pressure on the compressing tool. If O-ring type seals are used, carefully work the seals into the second groove of the valve (closest to the head), install the valve keepers and release the pressure on the tool.
If the O-ring seals are installed BEFORE the springs and retainers are compressed, the seal will be destroyed.
- After all of the valves are installed and retained, tap each valve spring retainer with a rubber mallet to seat the keepers in the retainer.