Pistons And Connecting Rod Overview

Fig 1: Identifying Assembly Overview: Pistons And Connecting Rod

Courtesy of VOLKSWAGEN UNITED STATES, INC.

1. Connecting Rod Bolt 
   • M8 bolt: 30 Nm + an additional 90° (1/4) turn.
   • M9 bolt: 45 Nm + an additional 90° (1/4) turn.
   • Always replace.
   • Lubricate the threads and contact surface.
   • Use an old bolt to measure the radial play.
   • Do not tighten the additional 90° (1/4) turn further when measuring the radial play.
2. Connecting Rod Bearing Cap 
   • Note the installed position.
   • Due to the separation procedure (cracking) for the connecting rod, the cap only fits in one position and only on the correct connecting rod.
   • Mark the affiliation to the cylinder -A-.
   • Installed position: Marks -B- point to the belt pulley side.
3. Bearing Shells 
   • Installed location, refer to Figure.
   • Do not interchange used bearing shells (mark them).
   • Axial play:

     New: 0.10 to 0.35 mm

     Wear limit: 0.40 mm.

   • Measure the radial clearance using Plastigage R :

     New: 0.02 to 0.06 mm

     Wear limit: 0.09 mm

   • Do not rotate the crankshaft when checking the radial clearance.
4. Pressure Relief Valve 
   • 27 Nm
   • Opening pressure 1.6 to 1.9 bar.
5. Oil Spray Jet 
   • For piston cooling.
6. Circlip 
7. Piston Pin 
   • If the piston is difficult to move, heat it to 60 °C (140 °F).
   • Remove and install using the pilot drift -VW 222 A-.
8. Piston 
   • Checking, refer to PISTON, CHECKING .
   • Mark the installed position and cylinder allocation.
   • The arrow on the piston face points toward the belt pulley side.
   • Install using a piston ring compressor.
   • Piston and cylinder dimensions. Refer to PISTON AND CYLINDER DIMENSIONS .
   • Cylinder bore checking. Refer to CYLINDER BORE, CHECKING .
9. Compression Rings 
   • Offset gaps by 120°.
   • Use piston ring pliers for removing and installing.
   • "TOP" mark must face up toward piston crown.
   • Checking ring gap. Refer to Fig 2.
   • Checking piston ring groove clearance. Refer to Fig 3.
10. Oil Scraping Ring 
    • 2 piece
    • Install the upper steel ring so the gap is offset by 120° to the neighboring compression ring.
    • Offset all oil scraping ring component gaps to each other.
    • Checking ring gap. Refer to Fig 2.
    • The side clearance cannot be measured.
11. Connecting Rod 
    • Only replace as a set.
    • Mark the affiliation to the cylinder -A-.
    • Installed position: Marks -B- point to the belt pulley side.

Fig 2: Identifying Piston Ring Gap

Courtesy of VOLKSWAGEN UNITED STATES, INC.

-- Push the ring squarely from above, down to approximately 15 mm from the bottom end of the cylinder. To do this, use a piston without rings.

Fig 3: Identifying Piston Ring Gap

Courtesy of VOLKSWAGEN UNITED STATES, INC.

-- Clean the ring grooves of the piston before checking.