VALVE SPRINGS

Far from just making sure valves close after they’ve been opened, valve springs play a crucial role in controlling the valvetrain as a whole. They ensure the valve is kept in contact with the camshaft (via followers, lifters, rockers, pushrods) to ensure the cam controls the motion of the valves.

It’s vital you use suitable valve springs for your chosen camshafts. If the springs are too soft, they won’t be able to keep control of the valve, resulting in valve float (as outlined in the ‘flank’ boxout). Also, if any of the installed height, seat pressures or distance between coils is incorrect, the engine will almost certainly underperform. In unfortunate cases, it may even destroy itself!

Valve springs with too much pressure for the application are just as bad — over-springing can cause the valves to shut too aggressively, causing damage to the valve seat and cylinder head.