Spring Calculator

Valvespring Load Estimation

Estimates minimum required open load to maintain valvetrain control given valve lift and duration at 0.050" tappet lift. An acceptable frequency is calculated assuming the profile has typical aggressiveness.

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Redline Engine Speed (rpm)

Tappet Duration @ 0.050" (degrees)

Developed with values typical of roller lifter applications

Valve Lift (in)

Typ. for Big Block Marine: 0.500-0.800

Valve Mass (g)

Typ. for Big Block Marine Intake: Steel: 160g-180g; Titanium: 115g-125g

Locks Mass (g)

Typ: Steel 6g-10g

Retainer Mass (g)

Typ: Dual Springs: Steel: 28g-35g Titanium: 18g-24g Beehive/Conical: 10g-14g (Chromoly Steel), 6g-9g (Tool Steel)

Spring Total Mass (g)

Typ: Dual Springs: 140g-165g Conical/Beehive: 60g-70g

Spring Type

CylindricalBeehive / Conical

Select a Rocker Arm

Aluminum Stud MountSteel Stud MountAluminum Shaft MountSteel Shaft MountForged Carbon Shaft Mount

Rocker Ratio

Typ: 1.6 (Less Ratio than Average) 1.7 (Most Common) 1.8 (More Ratio than Average) 1.9 (Few Run this Much Ratio in Marine)

Rocker Pivot Length (in)

1.650 Is most common in BBC

Rocker Pivot Length (mm)

Pushrod Mass (g)

5/16" Diameter: 60g-70g; 3/8" Diameter: 125-135g; 7/16" Diameter: 145g-160g

Lifter Mass (g)

Roller Lifters: Solid: 95g-130g; Hydraulic: 120g-150g

How Aggressive?

Conservative (Higher Spring Load)

Aggressive (Lower Spring Load)

Lofting (Professional Racing Only)

Conservative estimates trend towards avoiding separation / pumpup of lash adjusters (if equipped). Aggressive estimates may allow separation / lash adjuster pumpup (if equipped) under some conditions. Lofting estimates are for professional racing use only, on solid lifter systems, where separation is desired to increase performance at high speeds. Spintron validation is always required.

Effective Valvetrain Mass - Valve Side (g)

Valvetrain mass used in calculations, expressed on the valve side of the rocker.

Effective Valvetrain Mass with Safety Factor (g)

Peak Negative Valve Acceleration (mm/deg^2)

Peak Negative Acceleration w/r/t/ Time

Min Required Open Spring Load (N)

Min Required Open Spring Load (lbf)

Spring load over the nose required to avoid valvetrain separation. Includes typical dynamic safety factor.

Min Valvespring Frequency (Hz)

Frequency of spring that complements cam profiles with aggressiveness typical of entered valve lift and 0.050" duration values.

Outer Spring Mass (g)

Outer Spring Active Mass, Single Rate (g)

Outer Spring Active Mass, Dual Rate (with Damping Coils) (g)

Min Spring Rate (lbf/in)

Min Spring Rate is calculated from min frequency and assumes typical cylindrical spring active mass. Not valid for beehive/conical springs at this time.

Closed Load @ Min Spring Rate (lbf)

Closed load is calculated from Min Required Open Spring Load and Min Rate - for reference only

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If you’d like a professional opinion on your valvesprings, check out our valvetrain engineering services page.

The calculator above is not a substitute for proper engineering analysis – it is for estimation purposes only and is not valid for profiles asymmetrical in the negative acceleration region, or for “cheater cams” having a near dwell at max lift. It also does not consider pressure differential across the valves (turbo / supercharged applications). The calculation assumes that valvetrain separation (lofting) is not desired.