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Piston And Connecting Rod

WARNING: This page is about a different car, the 2022 Subaru WRX. However, it is still accessible from the selected car via links, so may be relevant.
G14610914Courtesy of SUBARU OF AMERICA, INC.
  1. Install the connecting rod bearing to the connecting rod and connecting rod cap.
  2. Install a new circlip on one side of the piston using a flat tip screwdriver.
    NOTE:
    • Be careful not damage the piston, by wrapping the tip of flat tip screwdriver with tape. 
    • Install the circlip so that its end part (a) does not match the circlip groove cutout portion (b). 
      G13198990Courtesy of SUBARU OF AMERICA, INC.
    • Make sure the circlip is firmly inserted into the circlip groove.
  3. Set the piston to the connecting rod.
    NOTE:

    Align the front mark of piston and the connecting rod direction correctly as shown in the figure. 

    G14610916Courtesy of SUBARU OF AMERICA, INC.
  4. Apply engine oil to the piston pin, and attach the piston pin.
  5. Install a new circlip on the piston using a flat tip screwdriver.
    NOTE:
    • Be careful not damage the piston and piston pin, by wrapping the tip of flat tip screwdriver with tape. 
    • Install the circlip so that its end part (a) does not match the circlip groove cutout portion (b). 
      G13198992Courtesy of SUBARU OF AMERICA, INC.
    • Make sure the circlip is firmly inserted into the circlip groove.
  6. Install the oil rings to the piston in the order of expander, lower rail and upper rail by hand.
    NOTE:

    Oil ring consists of the upper rail, expander and lower rail. 

    G14610918Courtesy of SUBARU OF AMERICA, INC.
    1. Set the ring gap of the expander to the position (A).
      G14610919Courtesy of SUBARU OF AMERICA, INC.
    2. Set the ring gap of the lower rail at position (B), located 60° counterclockwise from the position (A) in the figure.
      G14610920Courtesy of SUBARU OF AMERICA, INC.
    3. Set the ring gap of the upper rail at position (C), located 120° counterclockwise from the position (B) in the figure, and align the upper rail spin stopper (E) to the side hole (D) on the piston.
      G14610921Courtesy of SUBARU OF AMERICA, INC.
  7. Install the compression rings to the piston in the order of second ring and top ring, using piston ring expander.
    1. Set the ring gap of the second ring to the position (A) in the figure.
      NOTE:

      The ring mark (2AT) on the second ring should face the piston crown. 

      G13198997Courtesy of SUBARU OF AMERICA, INC.
    2. Set the ring gap of top ring at (B) in the figure on the 180° opposite direction of (A).
      NOTE:

      The ring mark (1AU) of the top ring should face the piston crown. 

      G13198998Courtesy of SUBARU OF AMERICA, INC.
  8. Check again that the piston rings are installed correctly.
    NOTE:

    Also check that the piston ring gap (except oil ring lower rail) is not positioned within the range of piston skirt extended line. 

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