Skoda Workshop Service and Repair Manuals

Piston and conrod - Summary of components

1 -	Piston rings

q	Offset joint 120°

q	use piston ring pliers for removing and installing

q	Marking „TOP“ faces up

q	Inspect gap clearance → Fig.

q	Inspect end clearance → Fig.

2 -

Piston

q	with combustion chamber

q	mark installation position and matching cylinder

q	Installation position and assignment of piston and cylinder → Fig.

q	arrow on piston crown faces towards the belt pulley side

q	use piston ring tensioning strap for installing

q	if cracks present on piston stem - replace piston

q	inspect piston projection at TDC → Chapter

q	Ø Piston: 79.47 mm

3 -	Piston pin

q	if stiff, heat piston to 60°C

q	with drift -VW 222A- removing and installing

4 -

Circlip

5 -

Conrod

q	replace as a set only

q	mark matching cylinder -arrows A-

q	Fitting position: Markings -arrows B- point towards the belt pulley side

6 -	Bearing shell

q	Check fitting position

q	Pay attention to version:

top bearing shell (towards the piston) must be in long wearing material

Distinguishing feature:

black marking on the contact surface near the separation point

q	do not mix up used bearing shells

q	insert bearing shells in the middle

q	check for firm seating

q	Axial clearance:

Wear limit: 0.37 mm

7 -	Cylinder block

q	inspect cylinder bore → Fig.

q	Ø Cylinder: 79.51 mm

8 -	Conrod bearing cap

q	Check fitting position

9 -	Oil injection nozzle

q	for piston cooling

10 -	Pressure relief valve, 25 Nm

q	replace without sealant

q	removing and installing → Fig.

11 -	Conrod bolt, 30 Nm + torque a further + 90° (1/4 turn)

q

replace

q	Oil thread and contact surface

Inspecting piston ring gap clearance Special tools and workshop equipment required t  Feeler gauge –  Insert ring at right angles from above down into lower cylinder opening, about 15 mm away from edge of cylinder.

Piston ring dimensions in mm	new	Wear limit
1. Compression ring	0,25...0,40	1,0
2. Compression ring	0,20...0,40	1,0
Oil scraper ring	0,25...0,50	1,0

Inspect piston ring end clearance Special tools and workshop equipment required t  Feeler gauge Clean before inspecting the annular groove of the piston.

Piston ring dimensions in mm	new	Wear limit
1. Compression ring	0,06...0,09	0,25
2. Compression ring	0,05...0,08	0,25
Oil scraper ring	0,03...0,06	0,15

Inspecting cylinder bore Special tools and workshop equipment required t  Internal precision measuring instrument 50...100 Piston dimension → Chapter (Pos. 2). Cylinder dimension → Chapter (Pos. 7). Test sequence –  Measure at 3 points crosswise in a transverse direction -A- and lengthwise -B-. Variations compared to nominal dimension max. 0.10 mm   Note Do not measure the cylinder bore if the cylinder block is fixed to the assembly stand with the engine mount -MP 1-202-, as this may result in incorrect measurements.

Piston fitting position and assignment of the piston/cylinder Special tools and workshop equipment required t  e.g. electric stylus Work procedure –  Mark installation position and assignment on inside of piston (not on piston crown), with e.g. an electric stylus. Piston in cylinder -1- and -2-: Large piston relief for inlet valve to flywheel side -arrows- Piston in cylinder -3-: Large piston relief for inlet valve to belt pulley side -arrow-   Note t  For new pistons the cylinder assignment is colour-coded on the piston crown. t  Piston in cylinder 1 and 2: Marking 1/2 t  Piston in cylinder 3: Marking 3

Oil spray nozzle and pressure valve 1 -  Screw with pressure valve 2 -  Oil spray nozzle (for cooling piston) l  Fitting position: Align the guide edge of the oil spray nozzle to the edge of the cylinder block being worked on.   Note t  The oil injection nozzles must not be bent. t  Replace the oil injection nozzles if they are bent.