SEAT Workshop Service and Repair Manuals

Piston and conrod: Assembly overview t  Checking the play between the piston rings → Fig. t  Checking ring-to-groove clearance → Fig. t  Checking cylinder bore → Fig. t  Installation position and piston/cylinder correspondence → Fig. t  Fitted position of the half bearings → Fig.

1 -	Piston rings

q	Offset gaps by 120°

q	Use piston ring pliers to remove and install

q	The mark „TOP“ must face towards piston crown

q	Checking ring gap → Fig.

q	Checking ring-to-groove clearance → Fig.

2 -

Piston

q	Mark installation position and cylinder number.

q	Installation position and allocation of piston to cylinder → Fig..

q	Arrow on piston crown points to pulley end

q	Install using piston ring clamp

q	If the piston is scratched, replace it

q	Position of the piston in TDC: verification → Chapter

3 -	Piston pin

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

q	Removing and installing with the awl -T20019-

4 -	Securing clip

5 -

Conrod

q	Mark cylinder allocation -A- with coloured pen.

q	Fitting position: The marks -B- should point towards the pulley

6 -	Bearing cap

q	Installation position → Fig.

q	Note design: Upper half bearing shell (to piston) made from high resistance material. Identification: Black line on the sliding surface in the cutting area

q	Do not interchange used bearing shells.

q	Axial play, wear limit: 0.37 mm

q	Check the radial play using a Plastigage: Wear limit: 0.08 mm when measuring the radial play, do not rotate the crankshaft

7 -	cylinder block

q	Checking cylinder bore → Fig.

q	Piston and cylinder dimensions → Chapter

8 -	Conrod bearing cap

q	Note fitting position:

9 -	Oil spray jet

q	For piston cooling

10 -	Hollow bolt with valve, -25 Nm

q

4x

q	Fit without using sealant

11 -	30 Nm + 90° (1/4 turn) further

q

Replace

q	Oil threads and contact surface.

q	Use old bolts when measuring radial clearance

Measurement of the play between the piston rings Special tools and workshop equipment required t  Calibre –  Insert ring at right angles from above into lower cylinder opening approx. 15 mm from edge of cylinder.

Piston ring Dimensions in mm	When new	Wear limit
1. compression ring	0,20 ... 0,40	1,0
2nd compression ring	0,20 ... 0,40	1,0
Oil scraping ring	0,25 ... 0,50	1,0

Checking ring-to-groove clearance Special tools and workshop equipment required t  Calibre –  First clean piston ring housing groove.

Piston ring Dimensions in mm	When new	Wear limit
1. compression ring	0,06 ... 0,09	0,25
2nd compression ring	0,05 ... 0,08	0,25
Oil scraping ring	0,03 ... 0,06	0,15

Check bore Special tools and workshop equipment required t  Internal dial gauge 50...100 mm –  Take measurements at 3 positions in both lateral direction -A- and longitudinal direction -B-. Deviations to the nominal value: Max. 0.10 mm   Note The measurement of the interior diameter of the cylinders cannot be done while the engine is attached to the engine assembly bench with the engine and gearbox support -T20172/3-, as doing so may result in erroneous measurements.

Installation position and piston/cylinder correspondence Pistons in cylinders 1 and 2: Large opening for the admission valve on the side of the engine flywheel -arrows-. Pistons in cylinders 3 and 4: Large opening for the admission valve on the side of the pulley -arrows-.   Note t  The new pistons carry the corresponding number for the cylinder marked in colour on the piston head. t  Pistons for cylinders 1 and 2: Numeration 1/2. t  Pistons for cylinders 3 and 4: Numeration 3/4.

Fitted position in the half bearings –  Fit the half bearings centred on the conrod and the conrod cover. Upper half bearing shell (to piston) made from high resistance material. Identification: Black line on the sliding surface in the cutting area. The measurement -a- must be the same to the left and right. Max. deviation: 0.2 mm