Skoda Workshop Service and Repair Manuals

Disassembling and assembling piston and conrod

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/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	inspect piston projection at TDC → Chapter

q	Piston dimenston: Ø 79.47 mm

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	pay attention to Part No.

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	Check fitting position

q	Pay attention to version: top bearing shell (towards the piston) must be in long wearing material

q	Distinguishing feature: black marking on the contact surface near the separation point

q	do not mix up used bearing shells (mark)

q	insert bearing shells in the centre

q	check for firm seating

q	Axial clearance: Wear limit 0.37 mm

7 -	Cylinder block

q	inspect cylinder bore → Fig.

q	Cylinder bore: Ø 79.51 mm

8 -	Conrod 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	before installing, oil thread and contact surfaces

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
1st compression ring	0,20...0,40	1,0
2nd 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
1st compression ring	0,06...0,09	0,25
2nd 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 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 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 Piston in cylinder 1 and 2: Large recess for inlet valve to flywheel side -arrows-. Piston in cylinder 3 and 4: Large recess for inlet valve to belt pulley side -arrows-.   Note t  For new pistons the cylinder assignment is colour-coded on the piston crown. t  Pistons in cylinders 1 and 2: Identification 1/2 t  Pistons in cylinders 3 and 4: Identification 3/4