SEAT Workshop Service and Repair Manuals

Dismantling and assembling piston and conrod

1 -	Piston rings

q	Offset gaps by 120°

q	Remove and install with piston ring pliers

q	Mark “TOP” faces towards piston crown

q	Checking ring gap → Fig.

q	Checking grove to ring clearance → Fig.

q	2 or 3 part oil scraper ring, mixed installation permitted

2 -

Piston

q	Checking → Fig.

q	Mark installation position and cylinder number

q	Arrow on piston crown points towards belt pulley end

q	Install using piston ring clamp

3 -	Piston pin

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

q	Remove and install with aid of -T20019-

4 -

Circlip

5 -

Conrod

q	Renew only as a set

q	Mark cylinder number -A-

q	Installation position: Mark -B- faces towards belt pulley end

6 -	Bearing shell

q	Do not interchange used bearing shells

q	Measuring pre-loading → Fig.

q	Fit bearing shells in centralized position

q	Measure radial clearance with Plastigage: New: 0,006…0,047 mm Wear limit: 0.091 mm Do not rotate crankshaft when checking radial clearance

7 -	Cylinder block

q	Checking cylinder bore → Fig.

q	Piston and cylinder dimensions → Chapter

8 -	Conrod cap

q	The caps only fit in one position on the respective conrod, this is due to the breaking procedure (cracking) separating the cap from the conrod

9 -	Conrod bolt

q	30 Nm + 1/4 turn (90°) further

q

Renew

q	Oil thread and contact surfaces

q	Tighten to a torque of 30 Nm but do not turn further when measuring radial clearance

Checking piston ring gap –  Push ring squarely from above down to approx. 15 mm from bottom edge of cylinder.

Piston ring Dimension in mm	New	Wear limit
1st compression ring	0,35…0,50	1,0
2nd compression ring	0,20…0,40	1,0
Oil scraper ring	0,25…0,75	--- → Note

1)  No wear limit details

Checking piston ring to piston groove clearance Clean groove before check.

Piston ring Dimension in mm	New	Wear limit
1st compression ring	0,04…0,075	0,15
2nd compression ring	0,02…0,05	0,15
Oil scraper ring	not measurable

Checking piston Special tools and workshop equipment required t  Micrometer 75…100 mm –  Measure pistons approx. 10 mm from the lower edge of skirt, at 90° to the piston pin axis. Deviation from nominal dimension max. 0.04 mm. Nominal dimensions → Chapter; Piston and cylinder dimensions

Checking cylinder bore Special tools and workshop equipment required t  Internal dial gauge 50…100 mm –  Measure bore at 3 locations in both directions -A- across the engine and -B- in line with the crankshaft. Deviation from nominal dimension max. 0.08 mm. Nominal dimensions → Chapter; Piston and cylinder dimensions   Note! Measuring the cylinder bores must not be carried out when the engine is mounted on a repair stand with engine bracket -AR-2204A-, as incorrect measurements would then be possible.

Measuring pre-loading on bearing shells Special tools and workshop equipment required t  Vernier gauge The pre-loading on the bearing shells is calculated as follows:

	Bearing shell dimension -a-
-	Diameter of conrod -b-
=	Pre-loading

Minimum dimension: 1.5 mm If the pre-loading is not achieved: –  Renew bearing shell.