Checking pistons and cylinder bores

⇒ 4.4.1 Checking piston

⇒ 4.4.2 Cylinder bore

⇒ 4.4.3 Piston and cylinder dimensions

4.4.1 Checking piston

Measuring piston ring gap

• Push piston ring at right angles to cylinder wall from above down into cylinder bore to approx. 15 mm from bottom end of cylinder.
• Push in using a piston without piston rings.

Measuring ring-to-groove clearance

• Clean annular groove of piston before check.

Checking piston

• Measure approx. 15 mm from lower edge, offset 90° from piston pin axis with a 75 to 100 mm external micrometer.

• Maximum deviation from nominal dimension: 0.04 mm.

Nominal dimension ⇒ 4.4.2 Cylinder bore

Installation position and allocation of piston to cylinder

• Arrow on piston crown points towards belt pulley end -arrows-.

• Centre bearing shells on conrod and on conrod bearing cap.

• Dimension -a- = 2.5 mm

• Measure approx. 15 mm from lower edge, offset 90° from piston pin axis with a 75 to 100 mm external micrometer.

• Maximum deviation from nominal dimension: 0.04 mm.

Nominal dimension ⇒ 4.4.3 Piston and cylinder dimensions

• Arrow on piston crown points towards belt pulley end -arrows-.

Installation position of bearing shells in conrods

• Centre bearing shells on conrod and on conrod bearing cap.

• Dimension -a- = 2.5 mm

4.4.2 Cylinder bore

Measuring

• Using cylinder gauge - VAS 6078- take measurements at 3 positions diagonally in lateral direction -A- and longitudinal direction -B-.

• Maximum deviation from nominal dimension: 0.10 mm.

Nominal dimension ⇒ 4.4.3 Piston and cylinder dimensions

4.4.3 Piston and cylinder dimensions