Valve Timing Overlap Calculator

Calculate valve overlap period and its effect on scavenging, EGR, and idle quality for cam profile analysis.

Input Parameters

Results

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Valve Overlap
° crank
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Intake Duration
°
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Exhaust Duration
°
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Lobe Separation Angle
°
Note: Overlap of 15-30° is typical for street cams. Race cams may use 60-80°+ overlap. Higher overlap improves scavenging at high RPM but hurts idle quality and low-end torque. SAE J604 cam terminology.

Reference

Overlap = IVO (BTDC) + EVC (ATDC) Intake Duration = IVO + 180 + IVC Exhaust Duration = EVO + 180 + EVC LSA = (Intake CL + Exhaust CL) / 2 Intake CL = ((180 + IVC) − IVO) / 2 + IVO