GMC Workshop Service and Repair Manuals

Piston Ring: Specifications

Piston Ring End Gap - Measured in Cylinder Bore
First Compression Ring
Production .........................................................................................................................................................................  0.23 - 0.44 mm (0.009 - 0.017 in)
Service ..............................................................................................................................................................................  0.23 - 0.5 mm (0.009 - 0.0196 in)

Second Compression Ring
Production ...........................................................................................................................................................................  0.44 - 0.7 mm (0.017 - 0.027 in)
Service ..............................................................................................................................................................................  0.44 - 0.76 mm (0.0173 - 0.03 in)

Oil Control Ring 
Production .........................................................................................................................................................................  0.18 - 0.75 mm (0.007 - 0.029 in)
Service ..............................................................................................................................................................................  0.18 - 0.81 mm (0.007 - 0.032 in)

Piston Ring-to-Groove Clearance
First Compression Ring
Production ...............................................................................................................................................................  0.04 - 0.085 mm (0.00157 - 0.00335 in)
Service ....................................................................................................................................................................  0.04 - 0.085 mm (0.00157 - 0.00335 in)

Second Compression Ring
Production .................................................................................................................................................................  0.04 - 0.078 mm (0.00157 - 0.0031 in)
Service ......................................................................................................................................................................  0.04 - 0.078 mm (0.00157 - 0.0031 in)

Oil Control Ring
Production .....................................................................................................................................................................  0.012 - 0.2 mm (0.0005 - 0.0078 in)
Service ..........................................................................................................................................................................  0.012 - 0.2 mm (0.0005 - 0.0078 in)