Volkswagen Workshop Service and Repair Manuals

Piston and rod - remove and install   Note Before performing assembly jobs it is necessary to lubricate support and sliding surfaces.

1 -

Piston

q	Check → Fig.

q	Mark assembly position and correspondence to respective cylinder

q	Piston head -arrow- must indicate pulley direction

q	Install with segment ring compressor

2 -	Piston pin

q	If applied for heavy duties, heat pistons at 60 °C

q	with 10-206: remove and install

3 -	Piston pin retaining ring

4 -

Rod

q	Replace only set

q	Mark correspondence to cylinder -A-

q	Assembly position: Marks -B- must point toward steering wheel

q	Axial gap piston/rod 0.20 to 0.40mm Wear limit 0.50 mm

5 -

Cap

q	Observe assembly position

q	Do not change used caps

q	Place caps centered

q	Measure radial gap with Plastigage: New: 0.010...0.057 mm Wear limit: 0.091 mm When measuring radial gap, do not turn crank shaft

6 -	Engine block

q	Check cylinders diameter → Fig.

q	Pistons and cylinders specifications → Chapter.

7 -	Rod covers

q	Observe assembly position

q	Rod covers may only be placed in one position and with corresponding rod

8 -	Rod bolt, 20 Nm + 90 °

q

Replace

q	Lubricate thread and support surface

q	To measure radial gap, tighten at 20 Nm, without angle torque

9 -	Oil scraper rings

q	Remove and install carefully, manually, oil scraper rings formed by 3 parts

q	Indication “TOP” must point toward piston head

q	Check interpoint openings of segment rings → Fig.

q	Check ring gap of ring on piston duct → Fig.

10 -	Compression segment rings

q	Openings moved in 120 °

q	Remove and install segment rings using ring pliers

q	Indication “TOP” must point toward piston head

q	Check interpoint gaps of segment rings → Fig.

q	Check ring gap of ring on piston duct → Fig.

Piston ring gap openings - check –  Place segment ring from above, so that it is in right angle on cylinder bottom opening, at distance of approx. 15 mm of cylinder edge.

Segment ring	New part Limit wear
1. Compression segment ring	0.15 to 0.30 1.0 mm
2. Compression segment ring	0.30 to 0.50 1.0 mm
Oil scraper ring	0.15 to 0.30 1.0 mm

Ring gap on piston duct - check. Previously clean housing duct of segment rings.

Segment ring	New part Limit wear
1. Compression segment ring	0.040 to 0.075 0.150mm
2. Compression segment ring	0.020 to 0.075 0.150mm
Oil scraper ring	0.010 to 0.176 0.186mm

Pistons - check Piston and rod - remove and install Special tools and workshop equipment required t  Micrometer 60...90 mm –  Measure at approx. 10 mm from lower edge, perpendicularly to piston pin axis. Difference in relation to nominal specification max. 0.04 mm. Nominal specification → Chapter; Pistons and cylinders specifications

Cylinder diameters - check Special tools and workshop equipment required t  Gauge 50...100 mm –  Measure in three points, in cross, in transversal and -A- longitudinal -B- directions. Tolerances in relation to nominal measure max. 0.08 mm. Nominal specification → Chapter; Piston and cylinder specifications   Note Cylinder internal diameter must not be measured when engine block is fixed to assembly anvil with Engine and gearbox support -VW 540-, as that may result is incorrect measures.