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 piston → Fig.. t  Installation position and piston/cylinder correspondence → Fig. t  Checking cylinder bore → Fig. t  Oil jets and pressure release valve → Fig. t  Separating new conrod → 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 -VW 222A-

4 -	Retainer washer

5 -

Conrod

q	Mark cylinder allocation -A- with coloured pen.

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

q	Bearing cap with fracturing centring

q	Conrod: separate → Fig.

q	Measuring radial clearance → Chapter

6 -	Bearing cap

q	Installation position → Fig.

q	Mark used bearing shells for re-installation but not on bearing surface

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

7 -	cylinder block

q	Checking cylinder bore → Fig.

q	Piston and cylinder dimensions → Chapter

8 -	Conrod bearing cap

q	Note fitting position:

q	Due to the cracking method used to separate the bearing cap from the conrod in manufacture, the caps only fit in one position and only on the appropriate conrod.

9 -	Oil spray jet

q	For piston cooling

10 -	Hollow bolt with valve, -25 Nm

q

4 units

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  Feeler gauge   Note Two different types of bolts are mounted, check which tool has to be used. –  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
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  Feeler gauge –  First clean piston ring housing groove.

Piston ring Dimensions in mm	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

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.

Installation position and piston/cylinder correspondence The arrow on the piston crown points to the cylinder 1 -arrows-.

Check bore 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.

Oil jets and pressure release valve 1 -  Bolt with pressure relief valve - 25 Nm 2 -  Oil spray jet for cooling piston

Separating new conrod On new conrods it is possible that the breaking point is not fully separated. If it is not possible to take off the conrod bearing cap by hand, proceed as follows: –  Mark the conrod correspondence to the cylinder –  Gently clamp conrod, as shown in illustration, in a vice with soft aluminium jaws.   Note t  Secure the conrod slowly so that it does not break. t  The conrod is attached below the cutting line. –  Unscrew 5 turns the two shock absorber bolts -arrows-.

–  Using a plastic hammer, carefully knock conrod bearing cap loose in direction of -arrow-.

Fitted position in the half bearings Bearing shell -1- with oil hole -arrow- for conrod. Bearing shell -2- without oil hole for conrod bearing cap. –  Centre the conrod bearings and the conrod bearing caps. Dimension -a- must be identical on both sides.