Skoda Workshop Service and Repair Manuals

Disassembling and assembling pistons and conrods

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 play in the slot → Fig.

2 -

Piston

q	with combustion chamber

q	mark installation position and matching cylinder

q	installation position and matching cylinder → Fig.

q	arrow on piston crown faces towards the belt pulley

q	use piston ring tensioning strap for installing

q	replace if cracks present

q	Check piston projection at top dead centre → Chapter

q	Piston dimension: Ø 80.96mm

3 -	Piston pin

q	if stiff, heat piston to approx. 60°C

4 -

Circlip

5 -

Conrod

q	with a split cover

q	There must be no dirt or burrs on fracture surfaces

q	separate new conrod → Chapter

q	Pay attention to the part number

q	always replace as a set only

q	pay attention to correct installation position

q	mark matching cylinder -A-

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

6 -	Bearing shell

q	Observe version: top bearing shell (towards the piston) must be made from a long lasting material

q	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 centre → Fig.

q	check for firm seating

q	Axial clearance: Wear limit 0.37 mm

7 -	Cylinder block

q	inspect cylinder bore → Fig.

q	Cylinder dimension: Ø 81.01 mm

8 -	Conrod bearing cap

q	cracked cover fits only in one position at the relevant conrod

q	There must be no dirt or burrs on fracture surfaces

q	pay attention to correct installation position

q	mark matching cylinder -A-

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

9 -	Oil injection nozzle

q	for piston cooling

10 -

25 Nm

q	replace without sealant

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

q

replace

q	Oil thread and contact surface

Fitting position of the bearing shells in the conrods –  The bearing shell in the centre of the conrod or the conrod bearing cap. l  The dimension -a- must be the same on the left and right.

Inspecting piston ring gap clearance –  Push in ring at right angles to the cylinder wall from the top through to the bottom cylinder opening, about 15 mm from the lower cylinder edge.

Piston ring	New mm	Wear limit mm
1. Compression ring	0,20...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 Clean ring grooves before inspecting.

Piston ring	New mm	Wear limit mm
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 fine measuring instrument 50...100 mm –  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 bores if the cylinder block is fixed to the assembly stand with the engine and gearbox mount -MP1-202-, as this may result in incorrect measurements.

Fitting position of piston and assignment of piston to cylinder Piston in cylinder 1 and 2: Large recess for inlet valve points to flywheel side -arrows-. Piston in cylinder 3 and 4: Large recess for inlet valve points to belt pulley side -arrows-.   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 and 4: Marking 3/4