Re: Double Valve Springs?

[Robert <rtchafin@xxxxxxxxxxxxx>]

Did you know there are also applications for triple valve springs?  
The reason for multiple valve springs, and especially for the double valve
springs that have been the subject of much speculation on the Digest, is
primarily to avoid the valve spring resonance that can occur at high RPM.
Valve springs are like any mechanical system:  they have a resonant
frequency that is a function of their mass (makes the frequency lower) and
their spring rate, or stiffness (makes the frequency higher). The bad thing
about resonance is that, when it occurs, the springs can no longer be
counted on the exert any force on the valves, and valve float occurs. This
is a BAD thing. 
Some builders counter this tendency by going to stiffer and stiffer valve
springs,  which increase stresses on the valve stems, tending to pull the
head off the valve; stiffer springs also increase the seating pressure,
which is good up to a point, but beyond that point tends to distort the
seats and the valve face itself.
The double valve springs take another approach: they reduce the mass of the
individual spring, thus increasing its' resonant speed,  while regaining
sufficient spring force by using a second (or third) spring.
I hope this explanation has been clear and sufficient.  
Robert

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