Specifications

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• RAMP: The textbook definition of ramp is the section of the cam from the base circle to
where the valve physically begins to open, or finishes closing. It is also commonly referred
to as a clearance ramp; or in other words the part of the cam lobe where the camshaft will
close up the initial tappet clearance (lash) and the tappet/follower will make initial contact
(on the opening side) or end its contact with the camshaft (on the closing side)
• FLANK: is defined as the end of the ramp section to the point where the valve reaches
maximum velocity.
• NOSE: is defined as the section between the maximum velocity on the opening side and
maximum velocity on the closed side, or rather the section of the cam where the valve
spring forces are keeping the valve train from separating from the cam surface.
• LOBE CENTER: is described as the maximum valve lift or nose center.
• TDC: Top Dead Center : This term is used when the piston is located on higher position
(Top)
• BDC: Bottom Dead Center : This term is used to define piston in Bottom position
• ATDC: After Top Dead Center => define piston position After TDC
• BTDC: Before Top Dead Center => define piston position Before TDC