SEAT Workshop Service and Repair Manuals

Dismantling and assembling pistons and conrods

1 -	Piston rings

q	Remove and install with piston ring pliers

q	Offset gaps by 120°

q	Check clearance

q	“TOP” faces towards piston crown

q	Checking ring gap → Fig.

q	Checking ring to groove clearance → Fig.

2 -

Piston

q	Mark installation position and correspondence with the cylinder

q	Installation position and piston/cylinder correspondence → Fig.

q	Check piston position at TDC → Chapter

q	Arrow on piston crown points to pulley end

3 -	Piston pin

q	Remove and install with -U-20008- tool

q	Pin diameter = 26 mm

4 -	Safety washer

5 -

Conrod

q	Only renew as a set

q	Mark correspondence with cylinder number -A-

q	The marks -B- must point to the distribution side

q	Conrod length = 144 mm

6 -	Conrod bearing shell

q	Note the fitting position

q	Do not interchange used bearing shells

q	Make sure the retaining lugs are correctly seated.

q	Axial clearance: Maximum: 0.37 mm

q	Check radial clearance with Plastigage: Maximum: 0.08 mm

q	Do not rotate the crankshaft when checking the radial clearance

7 -	Cylinder block

q	Checking cylinder bores → Fig.

q	Piston and cylinder dimensions → Chapter.

8 -	Conrod bearing cap

q	The marks -B- must point to the distribution side

9 -

Dowel peg

q	They should house firmly in the bearing and not in the cap

10 -	Oil injector

q	For piston cooling

11 -

10 Nm

q	Use suitable sealant for fitting

12 -	30 Nm + 1/4 turn (90°)

q

Renew

q	Oil the threads and contact surface

q	To measure the radial clearance use an old bolt

Ring gap: checking Special tools and workshop equipment required t  Feeler gauge Test sequence –  Insert the ring from the top and push ring squarely from above down to approx. 15 mm from the edge of the cylinder.

		Gap
Piston ring		New	Wear limit
1st compression ring	mm	0.20 … 0.40	1.0
2nd compression ring	mm	0.20 … 0.40	1.0
Oil scraper ring	mm	0.25 … 0.50	1.0

Ring to groove clearance: checking Special tools and workshop equipment required t  Feeler gauge Test sequence Clean groove before checking.

		Clearance
Piston ring		New	Wear limit
1st compression ring	mm	0.06 … 0.09	0.25
2nd compression ring	mm	0.05 … 0.08	0.25
Oil scraper ring	mm	0.03 … 0.06	0.15

Cylinder bores: checking Special tools and workshop equipment required t  Internal dial gauge 50 … 100 mm Test sequence –  Take measurements at 3 positions in both lateral -A- and longitudinal -B-. –  Maximum deviation from nominal dimension 0.08 mm.   Note! Measuring the cylinder bores must not be done when the cylinder block is mounted on a repair stand with adapter bracket -AR-2204A-, as incorrect measurements would then be possible.

Assembly position of pistons and piston/cylinder correspondence Pistons in cylinders 1 and 2: Large cut-out for inlet valve facing towards the flywheel -arrows- Pistons in cylinders 3 and 4: Large cut-out for inlet valve facing towards the pulley -arrows-   Note! t  New pistons have the numbers of the corresponding cylinders stamped on the crown. t  Pistons for cylinders 1 and 2: Numbers 1/2 t  Pistons for cylinders 3 and 4: Numbers 3/4