Volkswagen Workshop Service and Repair Manuals

Pistons and connecting rods - dismantle and assemble   WARNING Always replace self-locking nuts and screws subject to angular torque. BBX engine

1 -	Piston rings

q	Displace the opening by 120°.

q	Remove and install with ring pliers.

q	Reference “TOP” pointing towards the piston head.

q	Check opening between ends. → Fig.

q	Check ring clearance in the piston channel. → Fig.

2 -

Piston

q	Check → Fig.

q	Mark correspondence with the cylinder.

q	The arrow on piston head points to the pulley side.

q	Install with the ring tensioning strap.

3 -	Piston pin

q	In case of difficulties in the removal, heat the piston to 60° C.

q	Remove and install by using the Puller and Fitter - VW 222A-.

4 -	Retaining ring

q

Replace.

5 -	Connecting rod

q	With splitting (breaking) → Fig.

q	Only replace by complete set.

q	Mark correspondence with cylinder -B-.

q	Installation position: Markings -A- point towards the pulley side.

6 -	Bearing shell

q	Check the installation position → Fig.

q	Place bearing shells centered.

q	Do not invert bearing shells already used.

q	Ensure it is firmly fastened.

q	Clearance in the groove (new): 0.10...00.35 mm, Wear limit: 0.40 mm.

q	Measure radial clearance with “Plastigage” (new): 0.01...00.05 mm, Wear limit: 0.09 mm. Do not rotate the crankshaft when measuring radial gap.

7 -	Engine block

q	Check cylinder diameter → Fig.

q	Measures of the pistons and cylinders → Chapter.

8 -	Connecting rod cap

q	Pay attention on the installation position.

q	Due to splitting (breaking) of the connecting rods, the cap only seats in one position and with the corresponding connecting rod.

9 -

30 Nm 90°

q	Replace after each removal.

q	Lubricate the thread and the contact surface with oil.

q	To measure the radial clearance, tighten to 30 Nm only, without angular torque.

CFEA engine   WARNING Always replace self-locking nuts and screws subject to angular torque.

1 -	Segment rings

q	Displace the opening by 120°.

q	Remove and install with ring pliers.

q	Reference “TOP” pointing towards the piston head.

q	Check opening between ends → Fig.

q	Check ring clearance in the piston channel → Fig.

2 -

Piston

q	Check → Fig.

q	Mark correspondence with the cylinder.

q	The arrow on piston head points to the pulley side.

q	Install with the ring tensioning strap.

3 -	Piston pin

q	In case of difficulties in the removal, heat the piston to 60°C.

q	Remove and install by using the Puller and Fitter - VW 222A-.

4 -	Piston pin retaining ring

q

Replace.

5 -	Connecting rod

q	With broken cap.

q	Only replace by complete set.

q	Mark correspondence with cylinder -B-.

q	Installation position: marks -A- point towards pulley side.

6 -	Bearing shell

q	Pay attention to the assembly position.

q	Place bearing shells centered.

q	Do not invert bearing shells already used if they are going to be used again.

q	Check firm seating.

q	New axial clearance: 0.05...00.31 mm. Wear limit: 0.37 mm

q	Measure radial clearance with “Plastigage”: new: 0.01...00.05 mm. Wear limit: 0.09 mm. Do not rotate the crankshaft when measuring radial gap.

7 -	Engine block

q	Check cylinder diameter → Fig.

q	Measures of the pistons and cylinders → Chapter.

8 -	Connecting rod cap

q	Pay attention to the assembly position.

q	Due to splitting (breaking) of the connecting rods, the cap only seats in one position and fits only on the connecting rod to which it belongs.

9 -	Oil injector

q	For piston cooling.

10 -	Valve, 27 Nm

q	Opening pressure: 1.3...1.6 bar.

11 -

30 Nm 90°

q	Torx E 10.

q	Replace after each removal.

q	Lubricate the thread and supporting surface.

q	To measure the radial clearance, tighten to 30 Nm, without the angular torque.

Characteristics of broken connecting rod A - Conventional connecting rods (smooth separation surface) B - Broken connecting rods (rough separation surface)

Check opening between ring ends Special tools and workshop equipment required t  Feeler gauge Checking sequence –  Introduce ring, perpendicularly and from top, to the lower opening of the cylinder, at a distance of near 15 mm from the cylinder border.

Piston ring		Opening between ends
		new	Wear limit
Compression rings	mm	0,20...0,40	0,80
Oil scraper ring	mm	0,25...0,50	0,80

Ring clearance on the piston channel - check Special tools and workshop equipment required t  Feeler gauge Checking sequence Clean piston groove before checking.

Piston ring		Groove clearance
		new	Wear limit
Compression rings	mm	0,06...0,09	0,20
Oil scraper ring	mm	0,03...0,06	0,15

Pistons - check Special tools and workshop equipment required t  Micrometer 75..0.100 mm Checking sequence Measure at about 10 mm from the lower corner at a 90° angle in relation to the piston pin axis. Deviance from nominal measure max. 0.04 mm.

Assembly position of shells Bearing shell -1- with hole for oil -arrow- to the connecting rod. Bearing shell -2- without hole for oil to the connecting rod cap. –  Place the bearing shells, centred, on the connecting rod and connecting rod cap. Reading -a- must be the same on both the right and left sides.

Cylinder diameter - check Special tools and workshop equipment required t  Precision internal micrometer 50...100 mm t  Measure three different places, in cross pattern, in transversal -A- and -B- longitudinal directions with a distance of 10.0 mm from upper and lower edges-C-. Tolerances in relation to max. nominal measure 0.08 mm.   Note The bore may not be measured with the engine block fastened on the assembly stand with the Support -VW 540- or Rotary stand for engine and transmission -VAS 6095-, as measuring errors may occur.