What is the wear limit of an engine cylinder liner?
2 Answers
The wear limit of an engine cylinder liner is 0.50mm. Generally, if the wear exceeds 0.50mm, the cylinder liner needs to be replaced. Introduction to Cylinder Liners: A cylinder liner, short for cylinder sleeve, is embedded in the cylinder bore of the engine block and, together with the piston and cylinder head, forms the combustion chamber. Boring Standards: According to traditional engine repair specifications, piston rings come in standard sizes as well as oversized versions of 0.25mm, 0.50mm, 0.75mm, and 1.00mm, which serve as references for cylinder boring. In reality, cylinder liners wear unevenly, exhibiting eccentric ovality, scoring, and other conditions, making it impossible to bore the cylinder precisely to the wear value. Therefore, the actual measured wear value is typically increased by 0.25mm as the final boring standard (in some cases, even by 0.50mm, though considerations such as the hardness and strength of the cylinder liner surface prevent excessive enlargement).
We engine repair professionals all know that cylinder liner wear limits depend on actual measurement data. Using an inside micrometer, take six cross-measurements at the top, middle, and bottom positions of the cylinder block, then compare with factory cylinder bore specifications. For example, with a 1.6L Japanese car's factory spec around 76.5mm, if measurements exceed 0.15mm roundness or 0.25mm taper, it needs repair. Once when replacing piston rings on a 200,000km Corolla, we found the middle of the cylinder had worn 0.3mm more than the ends - the piston wobbled enough to fit a business card inside, requiring cylinder reboring. Regular oil changes during maintenance can delay wear, but when carbon buildup is severe, the oil ring can't scrape cleanly, accelerating cylinder wall damage.
