Connecting Rods by e2f57F39


									Connecting Rods
 Cast iron
 Forged steel – most common
 Aluminum – not for street use
 Titanium
 Plastic
 Powdered metal (PM)
Powdered Metal Rods
   Powdered metal rods are relatively strong, stable,
    and economical to produce.
   Powdered metal rods are made, in their final
    shape, from powdered metal which is pressed and
    heated until it fuses into a solid form.
   Powdered metal rods use a cracked cap design,
    which require special repair procedures.
Connecting Rod Design
   The connecting rod moves in both a rotating (big
    end) and reciprocating (small end) motion
   The connecting rod is designed to be as light as
    possible, but still have the required strength
   Under normal cylinder pressures a connecting rod
    has to transmit as much as 10,000 pounds of force
    from the piston to the crankshaft
Connecting Rod Small End
   Non-floating (pressed pin)
      Piston pin is held to the connecting rod by an
       interference fit
      Pin must be pressed out, and rod must be heated to
       install new piston and pin
   Floating
      Piston pin and small end of the rod have an oil
      Connecting rod must be drilled for pin oiling

      Retaining clips in piston keep the pin from falling out
Connecting Rod Inspection
   Big end
      Size

      Taper

      Out-of-round

      Surface finish

   Small end
      Size

      Surface finish

   Straightness
Connecting Rod Length
   Connecting rod length
    is measured from the
    centerline of the big
    end to the centerline
    of the small end
Rod Angularity
 Rod ratio = Rod CL to CL length
 Less rod angularity (higher number) creates
  less cylinder side loading
 Less rod angularity benefits high rpm
  operation the most
 Long rods or short stroke = Less angularity
Connecting Rod Preparation
 Remove casting flash and burs
 Polish along the length of the rod not across
 Magnaflux
 Check length
 Replace rod bolts

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