SEAT Workshop Service and Repair Manuals

Piston and connecting rod: disassembly and assembly

Before installation work, oil the support and slide surfaces.

1 -	Piston ring

q	Stagger the cuts in 120°

q	Remove and install with piston ring pliers

q	The mark “TOP” must point towards the piston head

q	Measure the play between the edges of the rings → Fig.

q	Measure the coupling play between the rings and the slots of the piston → Fig.

2 -

Piston

q	With combustion chamber

q	Mark the installation position and the correspondence to the respective cylinder

q	Installation position and piston/cylinder correspondence → Fig.

q	The arrow on the piston head must point towards the pulley

q	Install with ring fitting sleeve

q	If the piston rod is cracked, replace the piston

q	Test the position of the piston at TDC → Chapter

3 -	Piston rod

q	If movement is difficult, heat the piston to 60 °C

q	Remove and install with -T20019-

4 -	Lock washer

5 -	Connecting rod

q	Replace only the unit

q	Mark the correspondence to the cylinder -A-

q	Installation position: the marks -B- must point towards the pulley

6 -	Half-bearing

q	Check the installation position

q	Bear in mind the version: Upper half-bearing (towards the piston) of wear-resistant material Mark: Black strip on the slide surface, in the area of separation

q	Do not swap the used half-bearings

q	Fit and centre the half-bearings

q	Outer edge half-bearing to outer edge connecting rod/connecting rod cap 2.5 mm, measured on one side

q	Check for firm seating

q	Axial play Wear limit: 0.37 mm

q	Measure the radial play with Plastigage: Wear limit: 0.08 mm When measuring the radial play do not turn the crankshaft

7 -	Engine block

q	Measure the bore of the cylinders → Fig.

q	Dimensions of pistons and cylinders → Chapter

8 -	Connecting rod caps

q	Check the installation position

9 -	Oil injector

q	For cooling the pistons

q	Check the installation position: Turn the oil injector counter-clockwise until it touches the engine block and tighten it in this position

10 -

25 Nm

q	Fit without sealant

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

q

Replace

q	Lubricate the thread and the support surface

q	Tighten uniformly to a torque of 5 Nm

q	Use the old bolt to measure the radial play

Edges of the piston rings: testing play –  Fit the ring from above so that it is at a right angle to the lower opening of the cylinder, with a separation of approx. 15 mm from the edge of the cylinder.

Piston ring Dimensions in mm	New	Wear limit
1st compression ring	0.25...0.40	1.0
2nd compression ring	0.20...0.40	1.0
Oil scrapper ring	0.25...0.50	1.0

Test the coupling play between the rings and the slots of the piston First clean the piston housing slots.

Piston ring Dimensions in mm	New	Wear limit
1st compression ring	0.06...0.09	0.25
2nd compression ring	0.05...0.08	0.25
Oil scrapper ring	0.03...0.06	0.15

Measure the bore of the cylinders Special tools and workshop equipment required t  Interior callipers 50...100 mm –  Measure across three different points crosswise -A- and lengthwise -B-. Difference over the nominal dimension 0.10 mm max.   Note! Do not measure of the bore of the cylinders when the engine block is fixed to the installation trestle with engine support -Ar-2204 A-: doing so could result in erroneous measurements.

Installation position of pistons and piston/cylinder correspondence Pistons in cylinders 1 and 2: Large hole for intake valve towards the flywheel side -arrows-. Pistons in cylinders 3: Large hole for intake valve towards the pulley side -arrows-.   Note! t  The new pistons have the numbering of the corresponding cylinders in colour on the piston head. t  Pistons for cylinders 1 and 2: Numbering 1/2 t  Pistons for cylinder 3: Numbering 3