SEAT Workshop Service and Repair Manuals

Piston and conrod removing and installing

Before carrying out any assembly work, it is necessary to lubricate points of support and sliding surfaces

1 -

Piston

q	Checking → Fig.

q	Mark installation position and piston/cylinder correspondence

q	Arrow on piston crown points to crankshaft pulley end

q	Install using piston ring sleeve

q	Piston and cylinder dimensions → Chapter

2 -	Piston pin

q	If difficult to move, heat piston to 60°C

q	Remove and install with tool -T20019-

3 -	Safety washer

q

Renew

4 -

Conrod

q	Only renew as a set

q	Mark cylinder number -A-

q	Markings -B- should face towards pulley end

q	Guided axially via piston

5 -	Bearing shell

q	Do not interchange used bearing shells

q	Place bearing shells in correct position

q	Check radial clearance with Plastigage

q	New: 0,020 … 0,061 mm

q	Wear limit: 0.091mm

q	Do not rotate the crankshaft when checking the radial clearance

6 -	Cylinder block

q	Cylinder bores: checking → Fig.

q	Piston and cylinder dimensions → Chapter

7 -	Conrod bearing caps

q	Note the fitting position

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

8 -	30 Nm + 1/4 turn (90°)

q

Renew

q	Oil the threads and contact surface

q	To measure radial clearance tighten to 30 Nm but not further

9 -	Oil scraper rings

q	Carefully remove and install 3-part oil scraper rings by hand

q	“TOP” faces towards piston crown

q	Ring gap: checking → Fig.

q	Ring to groove clearance: checking → Fig.

10 -	Compression rings

q	Offset gaps by 120 °

q	Remove and install with piston ring pliers

q	“TOP” faces towards piston crown

q	Ring gap: checking → Fig.

q	Ring to groove clearance: checking → Fig.

Piston 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.

Piston ring	Wear limit
1. Compression ring	1.0 mm
2. Compression ring	1.0 mm
Oil scraper ring	1.0 mm

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

Piston ring	Wear limit
1. Compression ring	0.25 mm
2. Compression ring	0.15 mm
Oil scraper ring	0.15 mm

Pistons checking Special tools and workshop equipment required t  Micrometer 60 … 90 mm Test sequence Measure to approx. 10 mm from lower edge, at right angles to piston pin axis Deviation from nominal dimension: max. 0.07 mm Piston and cylinder dimensions → Chapter

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 transverse -A- and longitudinal -B- directions. –  Maximum deviation from nominal dimension 0.08 mm. Piston and cylinder dimensions → Chapter.   Note Checking the cylinder bores must not be done when the cylinder block is fixed to engine bracket -AR-2204A-, as incorrect measurements would then be possible.