Pistons And Connecting Rod Assembly Overview

Fig 1: Identifying Piston And Connecting Rod, Component Overview

Courtesy of AUDI OF AMERICA, LLC

1. Bolt
   • Replace
   • Lubricate threads and contact surface
   • 30 Nm plus an additional 90° (¹ /₄ ) turn.
   • Use old bolts for radial play measurement, tighten to 30 Nm but do not tighten further
2. Connecting Rod Bearing Cap
   • Affiliation to the cylinder mark -B-
   • Installation position: Markings -A- must align
3. Bearing Shells
   • Mark used bearing shells
   • Bearing shell retaining tabs must be firmly seated in the notches
   • Installation position: Retaining tabs of both bearing shells lie on the same side of the connecting rod
   • Measuring axial play, refer to CONNECTING ROD, MEASURING AXIAL CLEARANCE 
   • Radial clearance, measuring, refer to CONNECTING ROD, MEASURING RADIAL CLEARANCE 
   • Replacement parts are color coded "yellow" for lower and "red" for upper
4. Connecting Rod
   • With oil hole for piston pin lubrication
   • Only replace as set
   • Affiliation to the cylinder mark -B-
   • Installation position: -A- markings face toward lower side of piston crown (to center of cylinder block)
5. Circlip
6. Piston Pin
   • If tight, heat piston to 60 °C / 140 °F
   • Removing and installing using a drift VW 222 A
7. Piston
   • Checking, refer to Fig 4
   • Mark installed location to connecting rod and affiliation to cylinder
   • Shallow side of piston head faces cylinder block center
   • Piston and cylinder dimensions, refer to PISTON AND CYLINDER DIMENSIONS 
   • Install using fitting tool T10147, refer to Fig 6
8. Piston Rings
   • Compression rings
   • Offset gaps by 120°
   • Use piston ring pliers for removal and installation
   • Mark "TOP" must face toward piston head
   • Checking ring gap, refer to Fig 2
   • Check piston ring groove clearance, refer to Fig 3
9. Piston Ring
   • Oil scraping ring
   • 3-part
   • Install upper steel ring so gap is offset by 120° to neighboring compression ring
   • Offset all oil scraping ring component gaps to each other

Fig 2: Checking Piston Ring Gap

Courtesy of AUDI OF AMERICA, LLC

-- Slide piston ring from above into lower cylinder opening as follows, using piston without piston ring.

• Right angle to cylinder wall.
• Until approximately 15 mm from bottom edge of cylinder.

-- Measure with feeler gauge.

Fig 3: Checking Piston Ring Gap

Courtesy of AUDI OF AMERICA, LLC

-- Clean piston ring groove.

-- Measure with feeler gauge.

Fig 4: Checking Piston

Courtesy of AUDI OF AMERICA, LLC

-- Measure with external micrometer 75 to 100 mm as follows:

• Approximately 6 mm from bottom edge.
• Offset 90° to piston pin axle.

Deviation from nominal dimension:

• Maximum 0.04 mm.

Nominal dimension, refer to PISTON AND CYLINDER DIMENSIONS .

Fig 5: Checking Cylinder Bore

Courtesy of AUDI OF AMERICA, LLC

-- Measure with internal dial gauge 50 to 100 mm as follows:

• Diagonally at 3 positions transversely -A- and longitudinally -B-.

Deviation from nominal dimension:

• Maximum 0.08 mm.

Nominal dimension, refer to PISTON AND CYLINDER DIMENSIONS .

Fig 6: Identifying Piston With Funnel T10147, Installation

Courtesy of AUDI OF AMERICA, LLC

-- Push piston by hand into oiled piston installation tool.

• Flat side of piston crown must face toward funnel pin -arrow-.

-- Hold funnel (with piston inserted) on upper edge and press piston in with both thumbs.

-- Push piston in until it protrudes approximately 15 mm from lower edge of funnel.

-- Place pistons in appropriate cylinder bore.

• Funnel pin -arrow- must point toward center of cylinder block.

-- Press funnel tightly against cylinder block and push piston in.