VW Golf manuals

Volkswagen Golf Service & Repair Manual: Checking pistons and cylinder bores

Checking piston
–  Using a micrometre, measure approx. 10 mm from the lower edge, perpendicular to the piston pin axis.
Maximum deviation from nominal dimension: 0.04 mm
 

Checking pistons and cylinder bores

Piston diameter mm
Specification 74.42 1)
1) Dimensions without coating
Piston manufacturer Federal Mogul (thickness of 0.018 mm per side)
Piston manufacturer Mahle (thickness of 0.015 mm per side)
 
     
Measuring piston ring gap
–  Push piston ring at right angles to cylinder wall from above down into cylinder bore to approx. 15 mm from bottom end of cylinder.
–  Push in using a piston without piston rings.
 

Checking pistons and cylinder bores

Piston ring New mm Wear limit mm
Compression ring 0.20 + 0.15 1.0
Oil scraper ring (2 parts) 0.20 + 0.20 3.0
Oil scraper ring (3 parts) 0.50 +/- 0.25 3.0
 
     
Measuring ring-to-groove clearance
–  Clean annular groove of piston before check.
 

Checking pistons and cylinder bores

Piston ring New mm Wear limit mm
1st compression ring (piston ring manufacturer Federal Mogul) 0.050 … 0.090 0.15
1st compression ring (piston ring manufacturer Mahle) 0.035 … 0.085 0.15
2nd compression ring 0.030 … 0.070 0.15
Oil scraper rings (3 parts) Not measurable
Oil scraper rings (2 parts) 0.04 … 0.08
 
     
Measuring cylinder bore
Risk of damage to the surface of the cylinder bore caused by incorrect machining.Do not machine cylinder bore (reboring, honing, grinding) with workshop equipment.
–  Using cylinder gauge -VAS 6078- take measurements at 3 positions diagonally in lateral direction -A- and longitudinal direction -B-.
Maximum deviation from nominal dimension: 0.08 mm
 

Checking pistons and cylinder bores

Cylinder bore diameter mm
Specification 74.5 + 0.015 1) +0.005
 
  Note
Cylinder bores must not be measured when cylinder block is mounted on engine and gearbox support -VAS 6095-, as measurements may be incorrect.
   
Removing and installing oil spray jets
Special tools and workshop equipment required Socket -T10545- Removing –  Remove noi ...

Checking radial clearance of conrods
Special tools and workshop equipment required Plastigage Procedure –  Remove conrod ...

Other materials:

Retrofitting refrigerant circuit from R12 refrigerant to R134a refrigerant
Chlorofluorocarbon (CFC) is no longer used as a refrigerant in the automotive sector. R12Converting refrigerant circuits from refrigerant R12 to refrigerant R134a and repairing the converted circuits. → Repair ...

Checking the electrolyte level of the vehicle battery
Fig. 197 Engine compartment: pushing up the vehicle battery sleeve First read and observe the introductory information and safety warnings The electrolyte level of the vehicle battery should be checked regularly in high-mileage vehicles, in hot countries and in older vehicle batteries. T ...

Wheel bolts, versions
Explanations regarding types of convex seats There are two different versions of convex tapered seats, the spherical seat and the tapered.     The spherical seat is the curved surface of a s ...

© 2016-2022 Copyright www.vwgolf.org