Removal and Installation

Preparation
- Remove engine, refer to Removal/Installation. [1][2]Procedures
- Remove cylinder head. [1][2]Procedures
- Remove oil pan. Service and Repair

Matching Pistons To Cylinders (Part 1 Of 2):

Matching Pistons To Cylinders (Part 2 Of 2):

CAUTION: Cylinder identification and piston identifications must agree (see arrows).

NOTE:
- The group classification has been converted from numerals to letters and reduced to three stages.
- The pistons with numerals may be installed in a crankcase with a letter grouping, but not vice versa, refer to Matching Pistons to Cylinders. Application and ID
- When performing repairs, all the cylinder bores should be honed to the dimensions of the existing pistons plus piston play, refer to Size Honing and Silicone Lapping. Service and Repair
- The piston pins are matched to the pistons and must not be mixed up.
- The group number of the pistons (e.g. + 1) must agree with the group number of the cylinder bores (standard production).
- This ensures that the specified piston play is maintained.
- When performing repairs, all the cylinder bores should be honed to the dimensions of the exist. pistons plus piston play (see table).

Removal
1. Unbolt conrod bearing caps and lift out conrod together with pistons.

NOTE: Conrod and conrod bearing caps are marked together.

CAUTION: Do not damage cylinder contact surfaces with conrod.

2. Inspect conrod bolts. Application and ID





3. Use screwdriver to remove piston pin retainer and press out piston pin.
4. Service conrod and align, if necessary, refer to Repairing/Aligning Connecting Rod. Service and Repair

Installation

5. If pistons are worn, inspect gap end axial clearance of piston rings. Specifications
- Check that piston rings move freely.
- Pay attention to installation position.: "Top" faces up.
- Distribute ring gaps evenly around circumference.
6. Oil piston pin and conrod bushes.





7. Install piston so that the arrow faces in direction of travel and the locking slots in the conrod (arrows) as well as the drawing of the conrod are facing to the outside of the engine.

NOTE: The conrods are asymmetrical, the wide thrust collars point toward the crankshaft webs.





8. Press in piston pin by hand.





9. Insert piston pin retainer into the groove.
10. Oil cleaned cylinder bores, conrod bearing journals, conrod bearing shells and pistons.





11. Fit on tensioning strap for piston rings and insert piston into the cylinder bore with arrow facing direction of travel.

CAUTION: Do not damage cylinder contact surfaces with conrod.





12. Fit conrod bearing cap onto the conrod with the identification (arrow) facing each other.
- Moisten conrod nuts and thread and contact surface of conrod bolts with engine oil and tighten.
- Tightening torque, refer to Tightening Connecting Rod Bolts. Service and Repair

CAUTION:
- Pay attention to installation position of conrod bearings.
- Install conrod bearing shell with oil drilling in the conrod otherwise lubrication of the piston pin is not assured.

13. Rotate crankshaft and check whether it rotates freely.