🔍 Key Concepts

• Role of lubrication in reducing metal-to-metal contact between liners and piston rings • Normal visual appearance of properly lubricated cylinder surfaces versus scuffing, overheating, or varnish/deposit buildup • How free-moving rings versus tight/stuck rings relate to correct lubrication and ring/groove cleanliness

💭 Think About

• Think about what metal surfaces should look like if they are protected by the right amount of oil but not flooded or burned—would they be shiny and polished, or have a more even, matte wear pattern? • Consider what happens to piston rings if lubrication is poor (too little) or if excess oil causes deposits (too much). How would that affect ring freedom in the grooves? • Which choice best describes a condition where the engine has been working normally for a while with correct lubrication—not brand‑new parts and not a badly neglected cylinder?

✅ Before You Answer

• Make sure the ring condition (free vs. tight) matches what you would expect with good lubrication and clean grooves. • Check whether excessive oil deposits would be a sign of correct lubrication or over‑lubrication/poor combustion. • Decide whether a bright, polished surface usually indicates correct lubrication, or possible metal-to-metal contact and polishing from wear.