SEAT Workshop Service and Repair Manuals

Piston and conrod: Assembly overview t  Piston ring ends: check clearance → Fig. t  Check groove clearance → Fig. t  Checking piston → Fig. t  Checking cylinder bore → Fig. t  Installation position of the bearing shells in the conrods → Fig. t  Installation position and piston/cylinder correspondence → Fig.

1 -	Piston rings

q	Displace cutouts 120º

q	Remove and install using piston ring pliers.

q	The mark “TOP” must face towards piston crown

q	Piston ring: Checking end clearance → Fig.

q	Groove clearance: check → Fig.

2 -

Piston

q	With combustion chamber

q	Mark installation position and cylinder number.

q	Installation position and piston/cylinder correspondence → 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	Checking piston position at TDC → Chapter

3 -	Piston pin

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

q	Removing and installing with the awl -VW 222-

4 -	Securing ring

5 -

Conrod

q	Mark the correspondence to the cylinder -A- using a colour marker

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

q	With ruptured bearing caps

6 -	Bearing shell

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	Centrally align bearing shells on insertion

q	Check for secure seating.

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:

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

9 -	Oil injection nozzle

q	for piston cooling

10 -	Hollow bolt with valve, -25 Nm

q	Fit without using sealant

11 -	Conrod bolt, 30 Nm + 90° (1/4 turn)

q

Replace.

q	Oil threads and contact surface.

q	To measure the radial play use a used bolt

Check the contact play of the piston ring 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	New	Wear limit
1. Compression ring	0,20...0,40	1,0
2. Compression ring	0,20...0,40	1,0
Oil scraping ring	0,25...0,50	1,0

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

Piston ring Dimensions in mm	New	Wear limit
1. Compression ring	0,06...0,09	0,25
2. Compression ring	0,05...0,08	0,25
Oil scraping ring	0,03...0,06	0,15

Checking pistons –  Measure about 10 mm from the lower edge, at 90 º to the axis of the piston pin. l  Maximum deviation from the nominal dimension: max. 0.04 mm

Cylinder bore: Check Special tools and workshop equipment required t  Internal dial gauge 50 -100 mm –  Measure at three different points, crossways, across the engine -A- and in line with crankshaft -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 -VW 540-, as doing so may result in erroneous measurements.

Installation position of the bearing shells in the conrods –  Fit the bearing shells centrally in the conrod or in the conrod bearing cap. l  Dimension a = 2.5 mm

Installation position and piston/cylinder correspondence Pistons in cylinders 1 and 2: Large allotment for inlet valve towards flywheel side -arrows- Pistons in cylinders 3 and 4: Large allotment for inlet valve towards pulley side -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: Numbering 1/2 t  Pistons for cylinders 3 and 4: Numbering 3/4