1D-Cylinder Liner

Cylinder liner installation process detailed

First, dry cylinder liner installation: millimeter-level accuracy challenges

Core steps:

Cylinder block pretreatment:

Clean cylinder bore (roughness Ra≤1.6μm);

Measure the bore bore diameter (using a CMM, tolerance ±0.005mm).

Cylinder liner pressing:

Interference control: 0.03-0.06mm (cast iron liner) or 0.02-0.04mm (aluminum alloy liner);

Pressing speed: ≤0.5mm/s (using hydraulic press, the pressure needs to reach 50-100 tons).

Sealing test:

Helium leak detection (leakage rate ≤1×10⁻⁶ mbar · L/s);

Water pressure test (maintain no leakage at 0.5MPa pressure for 30 minutes).

Common problems:

Insufficient interference: resulting in cylinder liner loosening (knocking sound + power drop);

Push in tilt: out-of-ellipticity of cylinder liner (need to re-bore cylinder).

Second, wet cylinder liner installation: sealed life and death line

Key process:

Sealing ring installation:

Choose fluorine rubber O-ring (temperature resistance -40 ℃ to 200℃);

Apply a heat-resistant sealant (e.g. Loctite 518).

Cylinder liner bulge adjustment:

Protrusion: 0.05-0.15mm (using dial indicator measurement);

Adjustment method: Grind cylinder liner flange or replace gasket.

Cooling system flushing:

Use a special cleaning agent (e.g. BG 208) to remove scale;

Water quality test (conductivity ≤50μS/cm).

Typical case:

Volkswagen EA888 engine: The wet-type cylinder liner protrusions exceed 0.02mm, resulting in cylinder liner washout (maintenance cost exceeds 10,000 yuan).

Third, cylinder boring technology: the ultimate means of wear repair

Operation process:

Wear assessment:

Measuring cylinder diameter (using internal micrometer, ovality > 0.05mm to bore cylinder);

Check the scratch depth of cylinder wall (> 0.2mm cylinder liner needs to be replaced).

Boring process:

Rough boring: leave 0.2-0.3mm margin;

Precision boring: tolerance ±0.002mm;

Honing: Surface roughness Ra 0.8-1.6μm, mesh Angle 45°-60°.

Piston matching:

Piston and cylinder liner clearance: 0.03-0.06mm (gasoline engine) or 0.05-0.08mm (diesel engine).

Note:

Stress release should be carried out after cylinder boring (heating to 550℃ for 2 hours);

Do not use ordinary Oil running-in (high-phosphorus running-in oil, such as Rislone Engine Break-In Oil).

Four, owners to avoid the pit guide

Maintenance options:

The cost of dry cylinder boring is about 2000-5000 yuan, and the cost of wet cylinder replacement is 1500-3000 yuan;

The secondary cylinder liner price is only 60% of the original factory, but the life may be shortened by 30%.

DIY Risks:

Dry liner pressing requires professional equipment (such as German Hofmann pressing machine);

The wet cylinder liner seal ring is improperly installed, and the leakage probability is as high as 40%.

Summary: Cylinder liner installation is a precision engineering, it is recommended to choose 4S shop or professional cylinder boring factory (such as the United States Sunnen authorized service provider), to avoid secondary failures caused by process defects.