SEAT Workshop Service and Repair Manuals

Piston and conrod: Assembly overview   Note If large quantities of metal shavings or particles are found in the engine oil when repairing the engine, the oil passages must be cleaned carefully, and the oil cooler replaced in order to prevent further damage occurring later. → Fig. „„Checking piston ring gap““. → Fig. „„Checking ring-to-groove clearance““. → Fig. „„Checking pistons““. → Fig. „„Check bore““. → Fig. „„Assembly position of the bearing shell““. → Fig. „„Oil jets and pressure release valve““.

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

q

replace

q	Oil threads and contact surface.

q	Use old bolts when measuring radial clearance

q	When measuring radial clearance, tighten to 30 Nm but do not turn further

2 -	Conrod bearing cap

q	Mark cylinder number -B-

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

3 -	Bearing shells

q	upper bearing shell with oil drilling for piston pin lubrication

q	Installation position → Fig.

q	Do not interchange used bearing shells (mark).

q	Axial play, new: 0,10  ... 0.35 mm; wear out limit: 0.40 mm

q	Checking radial clearance with Plastigage: new: 0,01 ... 0.05 mm; wear out limit: 0.12 mm when measuring the radial play, do not rotate the crankshaft

4 -

Conrod

q	Can only be used as one unit

q	Mark cylinder number -B-

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

q	With oil drilling for piston pin lubrication

5 -

Circlip

6 -	Piston pin

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

q	Remove and install with the installation tool -VW 222A-, see equivalent → Anchor

7 -

Piston

q	check → Fig.

q	Mark installation position and cylinder number.

q	Arrow on piston crown points to pulley end

q	Install using piston ring clamp

q	Piston and cylinder dimensions → Chapter

q	Checking cylinder bore → Fig.

8 -	Piston rings

q	Displace the gaps at 120° from each other

q	Use piston ring pliers to remove and install

q	„TOP“ must face towards piston crown

q	Checking the play between the piston rings → Fig.

q	Checking ring-to-groove clearance → Fig.

Checking piston ring gap –  Insert ring at right angle to cylinder wall from above and push down into lower cylinder opening approx. 15 mm from bottom of cylinder. Use a piston without rings to push ring into bore.

Piston ring (in mm)	new	Wear limit
1. compression ring	0,20 … 0,40	0,8
2. compression ring	0,20 … 0,40	0,8
Oil scraping ring	0,25 … 0,50	0,8

Checking ring-to-groove clearance –  Before checking, clean the groove of the rings.

Piston ring (in mm)	new	Wear limit
1. compression ring	0,06 … 0,09	0,20
2. compression ring	0,05 … 0,08	0,20
Oil scraping ring	0,03 … 0,06	0,15

Checking pistons –  Measure approx. 10 mm from the bottom edge, perpendicular to the piston pin axis. l  Deviations in relation to max. specified measurement 0.04 mm.

Check bore –  Measure with an internal fine measurement device 50 … 100 mm at 3 different points transversely -A- and in the longitudinal direction-B- . l  Deviations in relation to max. specified measurement 0.08 mm.

Assembly position of the bearing shell –  Fit the bearing shells centrally in the conrod or in the conrod bearing cap. l  Dimension -a- = 3.0 mm

Oil jets and pressure release valve 1 -  Oil spray jet (for cooling of pistons) 2 -  Bolt with pressure relief valve -27 Nm l  Opening pressure: 1.3 - 1.6 bar.