SEAT Workshop Service and Repair Manuals

Piston and conrod - Components overview

Before carrying out assembly work, oil should be applied to the support and slide surfaces.

t	Piston and cylinder measurements → Chapter

1 -	Safety ring

2 -	Piston spring pin

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

q	Removing and installing with the tappet -T20019-

3 -

Piston

q	Testing → Fig.

q	Mark installation position and respective cylinder

q	The arrow on the piston head should point towards the pulley

q	Install using piston ring installation sleeve

4 -	Compression rings

q	Displace cutouts 120º

q	Remove and install compression rings using piston ring pliers

q	The labelling “TOP” must face towards piston crown

q	Ring ends: check clearance → Fig.

q	Checking piston ring side clearance checking → Fig.

5 -	Oil scraper rings

q	Carefully remove and install by hand the oil scraper rings made up of 3 parts

q	The labelling “TOP” must face towards piston crown

q	Ring ends: check clearance → Fig.

q	Checking piston ring side clearance checking → Fig.

6 -

Conrod

q	Renew as set only.

q	Mark cylinder assignment -A-

q	Installation position: The marks -B- should point in the direction of the pulley

q	Piston axial guided

7 -	Conrod bearing caps

q	Rods divided by fracturing “cracking” can only be fitted in one position and only with the corresponding conrod

8 -	Conrod bolt, tighten to 20 Nm +1/4 turn (90 °) further

q

Renew

q	Oil threads and contact surface.

q	To measure radial play, tighten to 20 Nm, without retightening

9 -	Engine block

q	Interior cylinder diameter: checking → Fig.

q	Piston and cylinder measurements → Chapter

10 -	Half bearing

q	Do not interchange used bearing shells

q	Centrally align bearing shells on insertion

q	Check the radial play using a Plastigage:

New: 0.020..0.00.061 mm

Wear limit: 0.091 mm

When measuring the radial play, do not rotate the crankshaft

Piston ring ends: check gap Special tools and workshop equipment required t  Gauge –  Insert ring at right angles from above into lower cylinder opening from of approx. 15 mm from the lower edge of the cylinder. For insertion, there must be no segments on the piston.

Piston ring Dimensions in mm	New	Wear limit
1. compression rings	0,20...0,50	1,0
2. compression rings	0,40...0,70	1,0
Oil scraper ring	0,25...0,50	--- → Note

1)  It is not possible to give an indication of the wear limit

Checking piston ring side clearance checking Special tools and workshop equipment required t  Gauge First clean piston ring housing groove.

Piston ring Dimensions in mm	New	Wear limit
1. compression rings	0,04...0,08	0,15
2. compression rings	0,02...0,06	0,15
Oil scraper ring	not measurable

Piston: checking Special tools and workshop equipment required t  Outer micrometer 75...100 mm –  Measure to approx. 10 mm from the lower edge, perpendicular to the shaft of the spring pin. Tolerance with respect to max. nominal measurement 0.04 mm. Nominal measurement → Chapter

Interior cylinder diameter: checking Special tools and workshop equipment required t  Internal dial gauge 50...100 mm –  Measure bores at three points in both directions: across the engine -A- and in line with crankshaft -B-. Tolerance with respect to max. nominal measurement 0.08 mm. Nominal measurement → Chapter.   Note Measuring the cylinder bores must not be done when the cylinder block is fixed to thecounterhold -T20172-, as incorrect measurements would then be possible.