Pistons, Checking

WARNING: This page is about a different car, the 2015 Volkswagen Beetle, 2014 Volkswagen Beetle, and 2013 Volkswagen Beetle. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Checking Piston Ring Gap

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Push the piston ring squarely from above down to approximately 15 mm from the bottom end of the cylinder.

-- Use a piston without a piston ring for sliding in.

Piston Ring	new mm	Wear limit mm
1. Compression ring	0.20 to 0.40	1.00
2. Compression ring	0.20 to 0.40	1.00
Oil scraping ring	0.25 to 0.50	1.00

Fig 2: Checking Piston Ring Gap

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Clean the piston ring groove before checking.

Piston Ring	new mm	Wear limit mm
1. Compression ring	0.06 to 0.09	0.25
2. Compression ring	0.05 to 0.08	0.25
Oil scraping ring	0.03 to 0.06	0.15

Fig 3: Checking Piston

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Measure approximately 15 mm from the lower edge at a 90° angle to the piston pin axis using a 75 to 100 mm external micrometer.

Maximum deviation from the specified dimension: 0.04 mm.

Nominal dimension. Refer to PISTON AND CYLINDER DIMENSIONS .

NOTE: A piston must be replaced if there are cracks on the piston shaft.

Fig 4: Identifying Installed Position Of Piston And Piston/Cylinder Allocation

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Arrow on the piston crown facing the pulley side -arrows-.

Fig 5: Identifying Installation Position Of Bearing Shells

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Install the bearing shells into the center of the connecting rod and into the connecting rod bearing cap.

Dimension -a- = 2.5 mm.