A Better Design (Continued)
The resultant design is a valve spring that is conical shaped (or Beehive shape as Comp's trademark reflects.) This design makes sense from a variety of standpoints. First, valvesprings unlike other types of spring uses, compress from the top down. The bottom coils, in fact, often don't compress at all. Therefore if the increase in pressure is created by the top most coils, while the bottom remain at a relatively lower rate, you end up with a spring that serves its valve control purpose, but also "dampens" the shock from the closing valve. This variable rate design also helps eliminate valvetrain harmonics - resonance frequencies that damage metals and lead to loss of control.

The benefits of conical springs doesn't end there. It turns out the design lends itself to a reduction in spring weight through three factors. First, the smaller coils up top means less material AND a smaller diameter retainer - weight saved. Second, the smaller coils and variation in coil spacing, yields spring rates that otherwise must be achieved through increased wire size - weight saved again. Finally, the harmonic dampening properties of a progressive rate spring and tapered wire allow eliminating the need for an inner second spring and damper - even more weight saved.

Give me the bottom line.
These seemingly small weight savings mean a lot in terms of power. Every gram of reduction in the moving valvetrain components frees up some 35 rpm. (Obviously the gram needs to be removed across all eight pairs of valves.) When you consider that a twenty-gram savings is on the low end of what can be achieved by just changing the spring set, you quickly see that an engine can spin another 700 rpm beyond its current redline. Some are quick to dismiss this as a mere extension at the end of an engines power curve. This is erroneous thinking. The majority of dyno sheets that show power flattening out or diving after peak power is made are not showing that the "cam is done", or "the heads are choking", but rather that the engine is likely experiencing the limitation of its valve springs. See the side bar on page 1 of AFR's real-world proof with their small block heads.

What's more is that these sorts of advantages are not just for deep-pocketed racers. Costs are quite reasonable for lighter valvesprings, retainers and locks. We took a look at a representative spring set for a small-block Ford with an agressive roller cam and the benefits and costs of putting the valvetrain on a diet.

Case Study: Comp Cams "986" Valve Spring
The Comp Cams 986 dual valve spring is a very popular standard-coil spring amongst the small block Ford crowd. Comp recommends it for pretty much all of their 5.0L and 351W hydraulic roller cams. However Comp also offers a Beehive version, PN: 26986. We take a look at the benefits of this spring.

The 986 spring assembly and standard steel retainers and locks weigh a total of 153.11 grams. Spring (PN 986): 116.25g Retainer (PN 740): 31.19g Locks (PN: 611): 5.67g Total Weight: 153.11g Total Cost: $168		In contrast, using the Comp Cams Beehive spring, PN: 26986 and the resulting smaller steel retainer, shaves nearly 40% off a single valve assembly. Spring (PN 26986): 76.54g Retainer (PN 795): 11.34g Locks (PN: 611): 5.67g Total: 93.55g Total Cost: $296
The Beehive 26986 spring (left) had a 1.412" OD at the seat while the 986 standard spring (dual) has an OD of 1.430". The freestanding heights are identical, yet the Beehive offers over 0.100" of bind clearance (1.040" versus 1.150") due to the ovate wire shape and single spring. This means you can run greater lift (.650" max) with lighter weight to boot.		The truth is in the valve spring tester. The 986 spring has a rate of 296 lbs.inch, and yeilds 132psi of pressure at an installed height of 1.750" (e.g. valve closed.) At 1.250" (simulating .500" lift) the pressure is 280psi. In comparison the Beehive 26986 is a 280 lbs./inch spring and yeilds 123psi. at 1.750" and 284psi at 1.175". While this seems to be less pressure, keep in mind that a heavier spring must use more pressure to control the mass of the spring. By reducing the weight of the spring assembly 39%, the 26986 assembly actually is able to apply more pressure to controlling the valve.
A secondary benefit to conical valve springs is the clearance gained between retainer and rocker arm. This is quite often an interference point with high-lift cams and/or increased ratio rocker arms.		There are more weight savings to be had by going to titanium retainers and locks. The 1.500" steel retainer and 11/32" 10° locks (right) weigh 36.85 grams combined. The titanium set weighs just 22.68 grams.

Five Tips for Finding Horsepower in your Valvetrain
	Use the lightest spring and retainer you can, and don't exceed recommended open pressure. Griffin says all hydraulic flat-tappet cams, and most hydraulic rollers, can use Beehive springs. For solid cams a conventional spring is usually best. Comp's online catalog has cross references where Beehive springs can be used in place of standard ones.
	Install springs 0.040-0.050" from coil bind. Amateur engine builders have a tendency to install valve springs based on their general catalog specifications. This often results in a spring that is too tall, which reduces valve control. Griffin recommends measuring actual valve lift and setting the installed height at this value plus 0.040-0.050" to avoid coil bind. Set up each spring individually, or at least setup the intake and exhaust spring sets separately.
	Buy the stiffest, largest diameter, pushrods you can run. All pushrods bend, but the question is how much. Bending reduces dynamic lift and duration. Therefore always run a high-quality hardened pushrod. Griffin also prefers steel rocker arms over aluminum for this reason.
	Buy your heads bare. Guys like Griffin, who really understand this stuff, would never settle for a pre-assembled set of heads. They buy their heads bare and then work up the valve train themselves. Buying bare heads also ensures you'll get steps 1-3 done your way, and not settle for a one-size fits all assembly
	Check your spring pressures every racing season (or every year for street cars) to make sure the pressures are within 5% of the catalog specifications. Springs that have been stressed will show marked pressure drops. Replace the entire set if neccesary.