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The 8 functions of the 8cylinder engine

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In a camshaft perspective its 8 functions. Most folks thought it was 4cycles.


Welp, im gonna explain the 8 so read on!


Exhaust open


Exhaust stroke


Intake stroke

Intake shut

Compression stroke

Expansion stroke


In the list above...one of the cylinders of a V8 is doing one of those functions. Altering the timing of one of the functions greatly changes the engines caracter. Hp, torque, power band location change.


Exhaust open is first camshaft mechanical Function.


Blowdown is spent combustion bleedoff meaning exhaust pressure still on the piston as the piston reaches the bottom.


Exhaust stroke is piston pushing the rest of exhaust out.


Overlap is where intake valve opens while exhaust being pushed out.


Intake stroke is piston pulling air in (or is the piston being driven to pull air in...hmmmm)


Intake shut is critical to begin compression.


Compression stroke, squeezing the mix


Expansion stroke is pushing the piston.


One can do the math of the camshafts technical points a derive how much the cam spends in limbo. Meaning piston not in expansion relative to the other 7 functions. Cause if you think about it, one piston in expansion has to make the other functions happen.

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