# Pistons, remove and install. S14

Remove cylinder head. |
Remove the eighteen 10mm lower oil pan bolts. |
Remove the 17mm nut securing gear to oil pump, slide gear off shaft and remove. |
Unscrew the two 13mm bolts retaining the oil pump to the cylinder block. |
Remove oil pump and any shims located between pump and block.
Remove reinforcement plate located at the rear of the oil pan. If necessary, loosen sway bar mounts to facilitate removal of reinforcement plate. |
Remove the twenty one 10mm bolts and remove upper oil pan. |
Remove cap from connecting rod and push piston out through top of engine. |
Remove the circlip retaining piston pin, slide out pin. Wrist pins are matched to pistons, and should be kept together. |
Connecting rods are also paired, pairing numbers are stamped onto both the rod and cap on the exhaust side. These numbers must match and all face the same direction. |

### Installation:

Use only pistons of the same make and weight class in the same engine.
Measure piston diameter 6mm from lower skirt edge. Measure cylinder bore at bottom, center and top. Installed clearance should be between 0.03mm (0.0012") and 0.06mm (0.0024"). Maximum permissible total wear play is 0.15mm (0.006")
Install piston on connecting rod and install wrist pin circlip with gap facing down.
Install a ring compressor on piston and install piston with arrow facing timing chain.

E30 M3 Repair Manual V2.7. Copyright ©1999-2001 Koala Motorsport & Brett Anderson