PerTronix’s new Digital HP ignition box

RACING VALVE SPRINGSSound Rules Text by Ben Mozart Photosto Courtesy Remember of PerTronix Performance Products Text by Archie Bosman Photos by Moore Good Ink

64 NOVEMBER.2017 EFORE STARTING THIS VALVE AGGRESSIVE spring longevity. SPRING STORY I THOUGHT I HAD AND WHEN THEY Race engine builder Jon A GRASP OF ITS MECHANICS, BUT UNDERMINE THE Kaase warns, “When the THEN AS IT DEVELOPED, IT BECAME COMBINATION valve-to-lifter assembly B Beyond these two leaves the lobe on the INCREASINGLY COMPLICATED, UNTIL I REACHED A POINT WHERE I DOUBTED IF I parameters—the amount opening side and comes HAD ANY INTUITIVE UNDERSTANDING OF of valve lift and engine crashing down on the HOW VALVE SPRINGS AND THEIR ATTENDANT speeds—there is the closing side, this affects VALVE GEAR FUNCTION. aggressiveness of the the entire valve train, Happily, the accumulated reams of profile to particularly valve springs. research data were simplified when Dick consider. Race engine It weakens them and can Boyer entered the picture. Here, courtesy builders frequently refer break them. It also injures of Erson , are several sound rules to to an aggressive lobe as solid roller lifter wheels remember. It’s a brief insight developed for a “square lobe,” which as it bangs them against those interested in high-performance engine conveys a somewhat the camshaft lobes.” technology that explains the severity of exaggerated mental Consequently, overly the environment in which the valve spring picture. “Aggressiveness” aggressive cam profiles operates and some of its relationships with in this context means how have a nullifying effect, most the various functions of the valve train. fast the valve is propelled notably when speeds Erson suggests that the primary factors off the . If it’s too outrun the valve events. considered when selecting valve springs in aggressive, at some point a racing engine are first, the amount of valve in the engine rev cycle it SEAT PRESSURES lift, and second, engine speeds. As engine will loft the lifter off the Springs are available as speed increases, so does inertia, which refers cam lobe, and the valve- singles, doubles or triples, to valve-train resistance to changes in speed train assembly will lose and they are selected by and direction. control. This is debilitating the amount of pressure With regard to the valve when it is fully as it undermines valve- required for the lifter open—at maximum valve lift—most engine builders desire the valve spring to be within 0.050 inch to 0.060 inch of coil bound. This almost coil-bound condition returns the coil It’s all about how hard you are pushing the spring to a uniform, stable shape on every closing cycle. limits. If you use the same spring for the intake and If not, the spring exhibits excessive space the exhaust, which we often do, the exhaust will between the coils and it cannot maintain its composure—it constantly shakes and last longer because it has more degrees of duration wiggles. Therefore, it could be argued that a valve spring operating at moderate lift that than the intake. —Jon Kaase, race engine builder doesn’t close properly is more inclined to ail with premature weakness or breakage than one operating with higher lift that does close properly.

If insufficient clearance exists between pocket wall and spring, machine pocket with spring seat cutter to prevent binding. By contrast, excessive clearance between the pocket wall and spring provokes unwanted, axial movement. Correct the problem by installing a spring cup.

65 DRAGRACERMAG.COM insufficient spring pressure, which will lead to failure. Engine builder Kevin Stoa adds, “You could have the best valve in the world, but if it floats, it can act like a jackhammer and break.” Often, the good name of the valve Most engine builders maker is blemished when the fault lies in arrange the valve spring inadequate spring pressure or the valve train to be within 0.050 inch to 0.060 inch of coil bound, going out of control. As a consequence, the which returns the spring to valve can be hammered, as Stoa indicates, a uniform, stable shape on until it breaks. every closing cycle. WHAT’S VALVE FLOAT? Valve float occurs when the valve train is Designed for professional and sportsman out of control. It’s when the lifters have lost contact with the lobes, when they no longer racers, Erson’s FSP series is aimed at drag racing, oval follow the cam. “If the valve train loses control track and endurance events as well as motorcycles. during a dynamometer pull, it is audible,” says Stoa. Instead of the air flow increasing These competition valve springs are created from or remaining linear, it decreases precipitously. The loss is also apparent in the numbers. super-clean, ultra-strong, specifically blended steel “The airflow might be 800 cfm, but if it alloy wire of the highest quality. encounters valve float, it will instantly drop to, say, 500 cfm or 600 cfm. The fix is not always simple, but initially, we might experiment by increasing valve spring pressure or reducing to follow the cam lobe. and camshafts ratio. Let’s say your rocker is 1.6:1, Naturally, you use the some engine builders adopt we might reduce it to 1.5:1.” lightest spring to control 200-pound seat pressures Jon Kaase tells us, “It’s all about how hard the valve—that is, to keep and beyond. you are pushing the limits. If you use the it closed and not allow it to But on Kaase’s Boss same spring for the intake and the exhaust, chatter—because the higher Nine hot rod engines, which we often do, the exhaust will last the spring pressure, the which use a hydraulic roller longer because it has more degrees of more power is absorbed by camshaft and operate with duration than the intake.” Sometimes Kaase the engine to operate it. If a single valve springs, the uses a similar cam lobe shape on both the single spring can control the seat pressure is around intake and the exhaust. “When you do this, valve, adding more spring 160 pounds. On its P-51 usually the springs act about the same, pressure will not generate race engines, which run except the intake is usually a little bit heavier, more power. On the other a solid roller cam and and so it might have a problem a little bit hand, pressure double springs, the seat earlier because of the additional weight.” will be lost if the valve pressures are 220 to 230 Of course, the spring not only closes chatters. Valve chatter or pounds. On the Mountain the valve but also controls the rocker arm valve bounce means the Motor Pro Stock race and pushrod mass. In addition, if the racer valve continues to bounce engines, seat pressures demands greater engine speeds, greater on the seat when it closes. are generated by triple lift requirements and the more aggressive Chatter is often caused by springs and maintained in camshaft lobes (faster and harsher), the insufficient valve-spring the 450-pound range. Valve heavier the valve spring must be. pressure or by the valve spring open pressures on Erson Cams, widely viewed as a leader in closing too aggressively, these engines operate at competition camshafts, has been providing despite, sometimes, the around 1,200 pounds. proprietary racing valves springs since the lifter following the cam Erson’s Dick Boyer agrees ’90s. Designed for professional and lobe faithfully. that the worst thing you sportsman racers, Erson’s FSP series is Seat pressures used can do is to lose valve train aimed at drag racing, oval track and with flat- camshafts control due to insufficient endurance events as well as motorcycles. are usually in the 120- to spring pressure. The These competition valve 140-pound range. However, horsepower loss caused springs are created from by employing careful by adding a little more super-clean, ultra-strong, Source ERSON CAMS running-in procedures with spring pressure is negligible specifically blended steel alloy 800.641.7920 expensive tool steel flat compared to the effects of wire of the highest quality. Pbm-erson.com

66 NOVEMBER.2017