Volkswagen Workshop Service and Repair Manuals

Assembly overview - pistons and conrods

1 -	Piston rings

q	Offset gaps by 120°.

q	Use piston ring pliers to remove and install.

q	„TOP“ faces towards piston crown.

q	Checking ring gap → Fig..

q	Checking ring-to-groove clearance → Fig..

2 -

Piston

q	With combustion chamber.

q	Mark installation position and cylinder number.

q	Installation position and allocation of piston to cylinder → Fig..

q	Arrow on piston crown points to belt pulley end.

q	Install using piston ring clamp.

q	If piston skirt is cracked, renew piston.

q	Checking piston projection at TDC → Chapter.

3 -	Piston pin

q	If difficult to remove, heat piston to 60 °C.

q	Remove and install using drift -VW 222-.

4 -

Circlip

5 -

Conrod

q	Mark cylinder allocation -A- with coloured pen.

q	Installation position: Marking -B- faces towards pulley end.

q	With industrially cracked conrod cap.

q	Separate new conrod → Chapter.

6 -	Bearing shell

q	Note installation position → Anchor.

q	Note version: Upper bearing shell (towards piston) is made of a more wear resistant material. Identification: Black line on bearing surface in area of joint.

q	Do not interchange used bearing shells.

q	Insert bearing shells centrally.

q	Check for secure seating.

q	Axial clearance, wear limit: 0.37 mm

q	Check radial clearance with Plastigage; wear limit: 0.08 mm.

q	Do not rotate crankshaft when checking radial clearance.

7 -	Cylinder block

q	Checking cylinder bores → Fig..

q	Piston and cylinder dimensions → Chapter.

8 -	Conrod bearing cap

q	Note installation position.

q	The caps only fit in one position and only on the appropriate conrod due to the breaking procedure (cracking) separating the cap from the conrod.

9 -	Oil spray jet

q	For piston cooling.

10 -

25 Nm

q	Insert without sealant.

11 -	Conrod bolt, 30 Nm + 90° further

q

Renew.

q	Oil threads and contact surface.

q	Use old bolt for measuring radial clearance.

Checking piston ring gap Special tools and workshop equipment required t  Feeler gauges –  Push piston ring squarely from above down to approx. 15 mm from bottom end of cylinder.

Piston ring dimensions in mm	New	Wear limit
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

Checking ring-to-groove clearance Special tools and workshop equipment required t  Feeler gauges –  Clean ring groove before checking.

Piston ring dimensions in mm	New	Wear limit
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

Checking cylinder bores Special tools and workshop equipment required t  Internal dial test indicator 50…100 mm –  Take measurements at 3 positions in both transverse -A- and longitudinal -B- directions, as illustrated. Difference between actual and nominal diameter max. 0.10 mm.   Note Cylinder bores must not be measured when the cylinder block is secured to engine and gearbox support -VAS 6095-, as measurements may be incorrect.

Installation position and allocation of piston to cylinder Arrow on piston crown -arrows- points in direction of cylinder 1. Installation position of conrod bearing shell

Bearing shell -1- with oil hole -arrow- for conrod. Bearing shell -2- without oil hole for conrod bearing cap. –  Position bearing shells in centre of conrod and conrod bearing cap when fitting. Dimension -a- must be identical on both sides.