CAMSHAFT, ROCKER ARMS, PUSHRODS (VALVE TRAIN)

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CAMSHAFT, ROCKER ARMS, PUSHRODS (VALVE TRAIN)

• MICKEY HO
• 4M D

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CAMSHAFT

• Lobes (Key component)
• Controls opening and closing of intake and
  exhaust valve
• Timed with motions of piston in cylinder
• Arrangements
• Single overhead cam
• Double overhead cam
• Pushrod

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Timing for Intake and Exhaust
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SOHC and DOHC

• SOHC one cam per head
• Cam controls both intake and exhaust
• DOHC two cam per head
• Intake and exhaust each has a cam
• Four or more valves per cylinder

Advantage Disadvantage
Higher engine speed Breakage in timing belt/chain
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PUSHROD

• Camshaft inside engine block
• Uses pushrods to control valves
• Less prone to breakage
• Limit engine speed

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REFERENCE

• http//auto.howstuffworks.com/camshaft.htm
• http//en.wikipedia.org/wiki/Four_stroke_engine
• http//www.allpar.com/eek/cams.html
• http//www.4cycle.com/karting/html/cam_theory.html