Fitting Pistons Audi A6 C5

1. Measure cylinder bore diameter in 3 places: at center of bore and.39" (10 mm) from top and bottom of bore. If cylinder bore diameter is not within specification, hone cylinder bore until diameter meets first oversize specification. See «CYLINDER BLOCK»(ref-147486-S02992587142002091600000) table under ENGINE SPECIFICATIONS.
2. Measure piston diameter at 90-degree angle to piston pin, about.39" (10 mm) from bottom of piston skirt. see scheme 99 If piston diameter is not within specification, replace piston. See «PISTONS, PINS & RINGS»(ref-147486-S41851760282002091600000) table under ENGINE SPECIFICATIONS. When measuring piston diameter, maximum allowable difference between actual measurement and standard specification is.0016" (.04 mm).

Scheme 85

Scheme 86

1. Install piston ring with TOP mark (if present) facing upward. Insert ring from bottom of cylinder block to a depth of about.591" (15 mm) to measure ring end gap. see scheme 100
2. Measure ring side clearance. see scheme 101 If ring end gap and side clearance are not within specification, replace ring and/or piston as necessary. See «PISTONS, PINS & RINGS»(ref-147486-S41851760282002091600000) table under ENGINE SPECIFICATIONS. Space ring end gaps 120 degrees apart.

Scheme 87

Scheme 88

1. Mark connecting rod and piston assemblies to identify which cylinder they belong to.
2. If replacing rods, replace entire set.
3. Replace bearing cap bolts and nuts with NEW nuts and bolts after each use.
4. Ensure arrow on piston (top or bottom) faces front end of engine when piston is installed.
5. A serrated connecting rod was placed into production on some engines starting in 1998. To identify the connecting rod type see scheme 102
6. The different design connecting rods use different size bolts. The serrated connecting rod uses M8 and M8.5 bolts. ALWAYS measure the threads as different tightening torques are used. See «TORQUE SPECIFICATIONS»(ref-147486-S30794586192002091600000).
7. Make sure connecting rods are installed in original positions. see scheme 103
8. If piston pin is difficult to remove, heat piston to 140°F (60°C).