10/7/2008
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Cylinder Wall De-Glazing VW 2.0L Engines
For correct piston ring sealing during the engine rebuilding process, use the following information:
• De-glaze cylinder walls using an 83 mm, 320 grit flexible ball-hone at 250-350 rpm.
• Lubricate cylinder walls with 10W-30 engine oil or honing oil, as recommended by the de-glazing ball-hone manufacturer.
• De-glaze the cylinders for approximately 20-45 seconds per cylinder.
Cross-hatch lines should intersect at an angle of approximately 45 degrees (see illustration):
• Too steep an angle will allow oil migration into cylinder, resulting in a thin oil film, which can cause ring and cylinder scuffing.
• Too flat an angle can hold excess oil, causing thicker oil films on which the piston ring rides up or “hydroplanes.”
• The cross-hatch angle on the cylinder wall is determined by the vertical speed of the ball-hone:
• Too slow a vertical ball-hone speed will result in too flat a cross-hatch angle; if the vertical speed of the ball hone is too rapid, the cross-hatch angle will be too steep.
• Cylinder cleaning is the single most critical step after de-glazing of the cylinder walls.
• Pistons, rings and cylinder bores will tolerate slight variations in roughness, cross-hatch angles, etc., but engine components will not tolerate honing stone residue.
After de-glazing, clean cylinders thoroughly with warm or hot water and detergent. Rinse with hot water and lightly oil cylinder walls to prevent rust.
Some or all of this information was provided by the Automotive
Parts Remanufacturers Association (APRA). For more information on
technical bulletins available through APRA call 703-968-2772 or visit www.AutoBulletins.com.
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