SEAT Workshop Service and Repair Manuals

Piston and conrod - assembly overview

1 -	Piston rings

q	Offset gaps by 120 °

q	Use piston ring pliers to remove and install

q	The mark „TOP“ faces towards piston crown

q	Checking ring gap → Fig.

q	Checking ring-to-groove clearance → Fig.

2 -

Piston

q	With combustion chamber

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	Checking piston position at TDC → Chapter

3 -	Piston pin

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

q	Remove and install with punch -VW 222- → Anchor

4 -

Circlip

5 -

Conrod

q	Mark cylinder allocation -A- with coloured pen.

q	Installation position: Marking -B- faces towards pulley end.

q	With industrially cracked conrod cap.

6 -	Bearing cap

q	Note fitting position:

q	Note design: Upper half-bearing (to piston) made from more resistant material. Difference: black line on the contact surface, in the separation area

q	Do not interchange used bearing shells.

q	Insert bearing shells centrally.

q	Check for secure seating

q	Axial play, wear limit: 0.37 mm

q	Check the radial clearance with plastigage; max. wear: 0.08 mm. Do not turn crankshaft when measuring radial clearance.

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 spray jet

q	For piston cooling

10 -	Bolt for oil spray jet

q

25 Nm

q	Fit without using sealant

11 -	Conrod bolt

q	30 Nm + 90° (1/4 turn)

q

Replace

q	Oil threads and contact surface.

q	Use old bolts when measuring radial clearance

Checking piston ring gap Special tools and workshop equipment required t  Feeler gauge –  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
2. 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 –  Clean the ring groove before the test.

Piston ring Dimensions in mm	When 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

Check bore Special tools and workshop equipment required t  Interior precision gauge (50 to 100 mm) –  Take measurements at 3 positions in both lateral direction -A- and longitudinal direction -B-. Difference between actual and nominal diameter: not more than 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.

Piston installation position and piston/cylinder assignment The arrow points to the cylinder 1 -arrows-.