Small Engine Camshafts

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Small Engine Camshafts
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Background

• Made of steel or cast iron
• Essential to keep motor running
• Super effective in improving performance

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Parts of the Camshaft
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What does it do?

• A camshaft lifts the valves to allow air and fuel
  into the cylinder and exhaust out
• It uses egg shape lobes pushing on lifters to do
  this process

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Gear Ratio

• The camshaft spins half the speed of the
  crankshaft
• The camshaft gear is twice the size of the
  crankshaft gear
• This is a 21 ratio

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Timing Marks

• Timing marks are aligned with the keyway
• They assure the valves are opening when
  appropriate

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Auto Compression Release

• Relieves compression by lifting exhaust valve
  slightly to make it easier to crank over a larger
  small engine

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Valve Springs

• Valves springs keep the valve face and seat
  sealed
• The spring is held in place by a retainer

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• V8
• Small engine

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How to Remove Camshaft

• Remove head, crankcase cover, flywheel and valve
  spring cover.

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• Compress springs and remove retainer

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• Slide out valves and keep exhaust and intake
  components separate.

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• Slide out camshaft and place exhaust and intake
  lifters in their assigned bags

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• When installing camshaft, make sure timing makes
  line up

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Camshaft Performance

• Larger lobes allow more air and fuel into the
  cylinder
• More air and fuel more power
• Lobes can be enlarged by lift or duration

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Horsepower Comparison

• Bolt on 1998 Camaro
• Z28
• Horsepower- 325
• Torque- 342
• Thats a 15 improvement

• Bolt on/ Cammed 1998 Camaro Z28
• Horsepower- 374.7
• Torque- 361
• (Cam Specs-
• 229/229 .585 .585 1144 cam)

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Review

• How many lobes does a camshaft have?
• How much bigger is the camshaft gear compared to
  the crankshaft gear?
• What is the purpose of timing marks?
• What does the auto compression release do?
• How many times does the piston move up and down
  to complete one rotation of the camshaft?

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Resources

• www.howstuffworks.com
• http//www.ul.ie/kirwanp/linkstoanimations.htm
• http//images.google.com/imghp?tabvi
• www.keveney.com