When valve speed increases by high rotation-ization of engine, 'valve bounce' may occur by the factory valve springs. Moreover, since inherent pitch is low, 'Surging' may occur in a high rotation region. In JUN, the valve spring with which the load optimal at the time of a set and a valve lift is acquired was manufactured. Even when the amount of valve lifts increases by using a high cam, since the adhesion margin is secured enough, the JUN valve springs does not have degradation and its durability is also improving.

Close adhesion between coil line will occur when the stock valve spring use together with high lift camshafts in a Nissan VR38DETT engine. Even if the coil line thin prepare as the simple way of solving it, it doesn't show enough load and strength. So, we designed special valve spring to get enough load and strength with thick coil line, and also designed special (offsetting) valve retainer. This valve spring set is a product which is including specail valve spring and special valve retainer (Type2).