Piston and rod - remove and install — VW

VW
Polo
2003
Engine
4 - Cyl. injection engine (4-valve, rolling rockers)
Edition
06.2002
Piston and rod - remove and install
Note
Before performing assembly jobs it is necessary to lubricate support and sliding surfaces.
Piston
Check
Fig.
Mark assembly position and correspondence to respective cylinder
Piston head
arrow
must indicate pulley direction
Install with segment ring compressor
Piston pin
If applied for heavy duties, heat pistons at 60 °C
with 10-206: remove and install
Piston pin retaining ring
Rod
Replace only set
Mark correspondence to cylinder
A
Assembly position: Marks
B
must point toward steering wheel
Axial gap piston/rod 0.20 to 0.40mm Wear limit 0.50 mm
Cap
Observe assembly position
Do not change used caps
Place caps centered
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
Engine block
Check cylinders diameter
Fig.
Pistons and cylinders specifications
Chapter
.
Rod covers
Observe assembly position
Rod covers may only be placed in one position and with corresponding rod
Rod bolt, 20 Nm + 90 °
Replace
Lubricate thread and support surface
To measure radial gap, tighten at 20 Nm, without angle torque
Oil scraper rings
Remove and install carefully, manually, oil scraper rings formed by 3 parts
Indication
“TOP”
must point toward piston head
Check interpoint openings of segment rings
Fig.
Check ring gap of ring on piston duct
Fig.
Compression segment rings
Openings moved in 120 °
Remove and install segment rings using ring pliers
Indication
“TOP”
must point toward piston head
Check interpoint gaps of segment rings
Fig.
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
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
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.