STK Performance Valve Springs

Dual Valve Spring sets consist of an innerspring and an outer spring per valve.

These springs are rated at 200 pounds pressure compared to a standard production spring of around 80 – 90 pounds pressure.
 
There are various modifications to ensure the correct fitment of these springs the main factor is to ensure that the customer is aware of the following:
  1. A 1mm spacer needs to be placed under the spring to avoid damage to the seating area.
  2. Stainless Steel Billet valves must be used otherwise the force of the valves closing will pull the head off a standard two-piece valve.
  3. Spring Travel & Spring pressures are crucial and will differ depending on the lift, duration and rpm range.
  4. The Spring sets are designed for up to 9000rpm, however we have clients revving close to 10 000rpm with reliability.
  5. STK Cam Buckets or similar should be used, the standard production Camfollowers are not strong enough to handle this spring kit.
Chromoly 4140 Valve Spring Retainers

Chromoly 4140 is a lightweight hardened steel.

This retainer is suitable for VW 7mm stems with 3 cotter grooves.

Use with standard 3-groove cotter.