Performance engine preparation. Valve events. What are they?. How are they measured?. Which cam lobe leads the other?. Performance engine preparation. Valve events. IVC (Intake valve closing). Determines effective compression ratio. Piston direction @ IVC ?.
What are they?
How are they measured?
Which cam lobe leads the other?
IVC (Intake valve closing)
EVO (Exhaust valve opening)
IVO (Intake valve opening)
EVC (Exhaust valve closing)
Duration – Valve open period
Lift – Cam lift or valve lift
Overlap – End of exhaust stroke, both valves are open
Base circle – Time valve is closed
Ramp – To take up valve train slack before opening
To reduce shock on valve closing
Flanks – Determine opening & closing rates
Limited by lifter diameter
Nose – Transition from opening to closing
Lobe centerline – Centerline of the lobe in relation
to crank angle
Lobe centers – Angle between intake & exhaust lobes
Lobe taper – For lifter rotation
Symmetrical cam lobes – Same opening & closing
contour of lobes
Asymmetrical cam lobes – Different contours ground on
opening & closing flanks
Dual pattern grinds – Intake & exhaust lobes ground to
different duration and/or lift