Manley 26180 Valve Spring & Retainer Kit For Subaru WRX/STI

Aftermarket cams increase the efficiency of your head by using higher lift and duration. Any time you increase the lift and duration of a cam, you are putting more stress on the valve springs and retainers. Factory valve springs were not made to handle the abuse of higher lift and duration, especially not at the rpm we take our engines to when racing, or even driving enthusiastically. If you are installing upgraded cams, do yourself a favor and install valve springs and retainers while you're in there.

Your stock valve springs can fail in 3 different ways. 

• BIND -

• They can "bind" and get stuck, losing their ability to open and close the valve. This is an easily diagnosable failure. Depending on how it binds, it could cause failure to other engine parts.

• BREAK -

• They can "break" into pieces dropping the valve into the combustion chamber and consequently ruining your bottom end.

• FLOAT -
  
  
• "Valve Float" is a hard to diagnose condition where the valve spring rate is not high enough to fully extend the spring and close the valve after a complete rotation of the cam before the cam comes back around again. So what ends up happening is that when the cam is spinning fast (high rpm) the valve never closes, and combustion leaks out of the engine, and the engine loses power.