Wondering if anyone knows what the formula is to calculate a cams overlap?

 

to calculate a cam's overlap you add the intake duration to the exhaust duration, divide that sum by 4, subtracting the LSA figure, finally multiplying the result by 2.

Example #1: (Comp Cams 224/236 cam)

Intake duration.....: 276 (@ .006)

Exhaust duration....: 288 (@ .006)

....................:===

=========total......: 564

Divide by 4.........: 564 / 4 = 141

Subtract LSA........: 141 - 112 = 29

Multiply result by 2: 29 * 2 = 58 degrees of overlap

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Example #2: (a generic Turbo cam)

Intake duration.....: 218 (@ .006)

Exhaust duration....: 212 (@ .006)

....................:===

=========total......: 430

Divide by 4.........: 430 / 4 = 107.5

Subtract LSA........: 107.5 - 114 = -6.5

Multiply result by 2: -6.5 * 2 = -13 degrees of overlap