SEAT Workshop Service and Repair Manuals

Piston and connecting rod disassemble and assemble

Engine code letters AEX

Engine code letters AER → Anchor

1 -	Piston rings

q	Push in 120°

q	Disassemble and assemble with pliers for piston rings

q	Manually disassemble and assemble with great care the lubrication rings made up of three parts

q	Mark “TOP” at the bottom of the piston

q	Check the impact play → Fig.

q	Check the height play → Fig.

2 -

Piston

q	Check → Fig.

q	Mark the assembly position and the belonging to the cylinder

q	The arrow at the bottom of the piston indicates the side of the pulley

q	Assemble with the tensing strap for the piston ring

3 -	Piston pin

q	Heat the piston to 60 °C in case of hard movement

q	Disassemble and assemble with -U-40077-

4 -	Safety ring

5 -	Connecting rod

q	Only replace by batches

q	Mark the belonging to the cylinder -A-

q	Assembly position: The -B- marks indicate the pulley

q	Axial guide for the piston

6 -	Bearing casing

q	Insert the bearing casing and centre it

q	Do not confuse the bearing casings that were in use

q	Measure the initial tension → Fig.

q	Measure the radial play with plastigage: New: 0.020...0.061 mm Wear limit: 0.091 mm Do not turn the crankshaft when the radial play is measured

7 -	Cylinder block

q	Check the cylinder hole → Fig.

q	Piston an cylinder dimensions → Chapter

8 -	Connecting rod cover

q	Remember the assembly position

q	If the connecting rods are fractured (cracked), the cover only fits in one position and only on the corresponding connecting rod

9 -	Connecting rod bolt M8: 30 Nm + turn 1/4 (90°) rotation more M7: 20 Nm + turn 1/4 (90°) rotation more

q

Replace

q	Lubricate the thread and the surface

q	To measure the radial play, tighten with 20 or 30 Nm, but without continuing to turn

Engine code letters AER

1 -	Safety ring

2 -	Piston pin

q	Heat the piston to 60 °C in case of hard movement

q	Disassemble and assemble with -U-40077-

3 -

Piston

q	Check → Fig.

q	Mark the assembly position and the belonging to the cylinder

q	The arrow at the bottom of the piston indicates the side of the pulley

q	Assemble with the tensing strap for the piston ring

4 -	Piston rings

q	Push in 120°

q	Disassemble and assemble the compression rings with the piston ring pliers

q	Manually disassemble and assemble with great care the lubrication rings made up of three parts

t	Mark “TOP” at the bottom of the piston

t	Check the impact play → Fig.

t	Check the height play → Fig.

5 -	Connecting rod

q	Only replace by batches

q	Mark the belonging to the cylinder -A-

q	Assembly position: The -B- marks indicate the pulley

q	Axial guide for the piston

6 -	Connecting rod cover

q	If the connecting rods are fractured (cracked), the cover only fits in one position and only on the corresponding connecting rod

7 -	Connecting rod bolt, 20 Nm + turn 1/4 (90°) rotation more

q

Replace

q	Lubricate the thread and the surface

q	To measure the radial play, tighten with 20 Nm , but without continuing to turn

8 -	Cylinder block

q	Check the cylinder hole → Fig.

q	Piston an cylinder dimensions → Chapter

9 -	Bearing casing

q	Do not confuse the bearing casings that were in use

q	Measure the initial tension → Fig.

q	Insert the bearing casing and centre it

q	Measure the radial play with plastigage: New: 0.020...0.061 mm Wear limit: 0.091 mm Do not turn the crankshaft when the radial play is measured

Check the impact play of the piston ring –  From above, insert the ring with a straight angle into the lower opening of the cylinder that is situated about 15 mm from the edge of the cylinder.

Piston ring	Wear limit
Compression rings	1.0 mm
Lubrication ring consisting of one part consisting of three parts	1.0 mm -- → Note

1)  It is not impossible to indicate the wear limit.

Check the height play of the piston ring Clean the ring channel before checking.

Piston ring	Wear limit
Compression rings	0.15 mm
Lubrication ring consisting of one part	0.15 mm
Consisting of three parts	not measurable

Check the piston Special tools and workshop equipment required t  Micrometer for exteriors 75...100 mm –  Measure at approx. 10 mm from the lower edge, about 90° displaced with regard to the shaft of the piston pin. Variation to the minimum measurement max. 0.04 mm

Check the cylinder hole Special tools and workshop equipment required t  Interior measurement and precision device 50...100 mm –  Measure at three points crossing the transversal direction -A- and longitudinal -B-. Variations to the minimum measurement max. 0.08 mm   Note! The cylinder hole should not be measured if the cylinder block and the engine support -VW 540- are fastened onto the assembly trestle, as erroneous measurements could result.

Measure the initial tension of the bearing casings Special tools and workshop equipment required t  Measurement pin The initial tension of the bearing casing is calculated as follows: Measurement -a- from the bearing casing - Connecting rod diameter-b- = Initial tension Minimum measurement: 1.5 mm If the initial tension is not reached: –  Replace the bearing casing.