SEAT Workshop Service and Repair Manuals

Piston, connecting rod, and casing: removing and installing

1 -	Safety cotter pin

2 -	Piston pin

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

q	Remove and install with -T20019-

3 -

Piston

q	Mark the fitting position and correspondence with respective casing/cylinder

q	The arrow on the piston head indicates the engine's turning direction (towards the camshaft side)

q	Install with casing to fit rings

q	Only install pistons of the same weight category (+ or - on the piston head)

q	Only available as a replacement part together with the casing

4 -	Piston rings

q	Stagger the cuts by 120°

q	Remove and install the compression rings using ring pliers

q	Carefully remove and install by hand the 3 piece oil scraper rings

q	The inscription “TOP” should must indicate the piston head

q	Check the play between the ends of the rings → Fig.

q	Check the coupling play between the rings and the grooves in the piston → Fig.

5 -	Connecting rod

q	Replacement part only available as a complete set (four rods)

q	Mark correspondence to cylinder → Item

q	Fitting position: The marks -B- must point towards the distribution

q	Axial guidance by piston

6 -	Connecting rod caps

q	In the case of fractured or “cracked” connecting rods, the cap can only be fitted in one position and only on its corresponding connecting rod

7 -	Connecting rod bolt, 20 Nm + 1/4 of turn (90°)

q

Renew

q	Lubricate the threads and the contact surface

q	In order to measure radial play, tighten to 20 Nm, without retightening

8 -	Engine block

q	The surfaces where the casings will go must be clean and even

q	Remove dirt and grime from the surfaces only by cleaning; do not use sandpaper, scraper or the like

9 -	Half bearings

q	Fit the centred half bearings

q	Do not interchange the used half bearings

q	Measure pre-tension → Fig.

q	Measure radial play with Plastigage: New: 0.020...0.061 mm Wear limit: 0.091 mm When measuring radial play do not turn crankshaft

10 -

Washer

q

Renew

q	To correct the casing's pre-tension

11 -

Casing

q	Observe the weight category (+ or - on the piston head)

q	Only available as a replacement part together with the the piston

q	Measure the pre-tension → Fig.

Check the play between the ends of the piston rings Special tools and workshop equipment required t  Gauge –  Fit the ring from above in such a way that it forms a right angle with the top casing/cylinder opening, and at a distance of approximately 15 mm from the edge of the casing/cylinder.

Piston ring Dimensions in mm	New	Wear limit
1st compression ring	0.20...0.50	1.0
2nd compression ring	0.20...0.50	1.0
Scraper ring	0.40...1.40	-- → Note

1)  It is not possible to provide an indication regarding the wear limit.

Check the coupling play between the rings and the grooves in the piston Special tools and workshop equipment required t  Gauge First clean the piston ring grooves

Piston ring Dimensions in mm	New	Wear limit
1st compression ring	0.04...0.08	0.15
2nd compression ring	0.04...0.08	0.15
Scraper ring	not measured

Measure the pre-tension of the the half bearings Special tools and workshop equipment required t  Gauge The half bearing's pre-tension is calculated in the following way: Dimension -a- of half bearing diameter of the connecting rod -b- = pre-tension Minimum diemension: 1.5 mm If pre-tension is not reached: –  Renew the half bearing.

Measure the casing's pre-tension Special tools and workshop equipment required t  Setting bar for dial gauge -T20026- support –  Place a wood or plastic wedge over the casing to be checked and eliminate any projections using a plastic hammer. –  Fit the support setting bar -T20026- so that the point of the comparison gauge works on the upper edge of the casing -arrow A- (make a note of the measurement taken), then work on the upper edge of the engine block -arrow B-. –  The difference between the two values obtained (pre-tension) must be between 0.07...0.12 mm.   Note! t  During measurement, the casing must be correctly placed (not askew) over the engine block's resting surface. t  Compensating washers measuring 0.10 mm, 0.12 mm, and 0.14 mm are available for this purpose. t  The difference between each casing may be a maximum of 0.4 mm.