Skoda Workshop Service and Repair Manuals

Summary of components - engines with identification characters AVU, BFQ

For carrying out removal and installation operation, attach the engine with the engine holder -MP1-202- and the sleeves -T30010- to the assembly stand -MP9-101-.

1 -

Circlip

2 -	Piston pin

q	if stiff, heat piston to 60°C

q	use drift -VW 222 A- for removing and installing

3 -

Piston

q	check → Fig.

q	mark installation position relative to conrod and mark matching cylinder with felt pen

q	arrow on the piston crown faces towards the belt pulley side

q	use piston ring tensioning strap for installing

q	Ø Piston 80.965 mm - without graphite coating 0.02 mm

4 -	Piston ring (compression ring)

q	Offset joint 120°

q	use piston ring pliers for removing and installing compression rings

q	marking „TOP“ must face towards piston crown

q	Inspect gap clearance → Fig.

q	Inspect end clearance → Fig.

5 -	Piston ring (oil scraper ring)

q	carefully remove and install by hand

q	marking „TOP“ must face towards piston crown

q	Inspect gap clearance → Fig.

q	Inspect end clearance → Fig.

6 -

Conrod

q	replace as a set only

q	separate new conrod → Chapter

q	mark assignment to cylinder -B-

q	Fitting position:

Markings -A- must be positioned one above the other and point to the belt pulley side

q	with oil drilling for lubricating piston pin

7 -	Conrod bearing cap

q	as a result of the conrods separated in the cracking process, the cover fits only in one position and only to the relevant conrod

q	mark assignment to cylinder -B-

q	Fitting position:

Markings -A- must be positioned one above the other and point to the belt pulley side

8 -	30 Nm + torque a further 90° (1/4 turn)

q

replace

q	Oil thread and contact surface

9 -	Pressure relief valve, 27 Nm

q

opens at:

0.13…0.16 MPa (1.3…1.6 bar)

q	replace without sealant

10 -	Oil injection nozzle

q	for piston cooling

11 -	Cylinder block

q	inspect cylinder bore → Fig.

q	Ø Cylinder 81.01 mm

12 -	Bearing shell

q	check fitting position → Fig.

q	do not mix up used bearing shells

q	insert bearing shells in the centre

q	Axial play when new: 0,05…0,31 mm

Wear limit: 0,37 mm

q	with oil drilling -arrow- for lubricating piston pin

Inspecting piston ring gap clearance Special tools and workshop equipment required t  Feeler gauges –  Insert ring at right angles from above down into lower cylinder opening, about 15 mm away from edge of cylinder. To insert use piston without rings.

Piston ring	Gap clearance
	new (mm)	Wear limit (mm)
Compression rings	0,75…1,00	1,3…1,4
Oil scraper ring	0,25…0,50	0,80

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

Piston ring	End clearance
	new (mm)	Wear limit (mm)
Compression rings	0,06…0,09	0,20
Oil scraper ring	0,03…0,06	0,15

Inspecting pistons Special tools and workshop equipment required t  External micrometer 75...100 mm –  Measure about 10 mm from the lower edge, offset at right angles to the piston pin shaft. Deviations from specified dimension: max. 0.04 mm

Bearing shell installation position Bearing shell -1- with oil drilling -arrow- for conrod. Bearing shell -2- without oil drilling for conrod bearing cap. –  Insert bearing shells in the conrod and in the conrod bearing cap centred. Dimension -a- must be the same on right and left, max. variation: 0.2 mm.

Inspecting cylinder bore Special tools and workshop equipment required t  Internal precision measuring instrument 50...100 mm Test sequence –  Measure at three points crosswise in a transverse direction -A- and lengthwise -B-. Deviations from specified 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 -MP1-202-, as this may result in incorrect measurements.