🔍 Key Concepts

• Piston cooling methods – look at any drilled passages through the connecting rod and into the piston crown or gallery. • Heat dam location – where is a groove or land cut to reduce heat transfer to the ring belt, and which ring is just below it? • Piston pin mounting – decide whether the wrist pin appears fixed in the rod eye or free to move in the bushing and piston bosses.

💭 Think About

• In the illustration, trace the path of oil shown at the lower end and along the connecting rod. Does it clearly reach the piston crown, or does it only lubricate bearings? • Find the groove or step that could act as a heat dam. Is it located above the top compression ring, or down near the oil scraper rings? • Look closely at the small end of the connecting rod: does the pin appear clamped to the rod or retained so it can float in the bushing and piston bosses?

✅ Before You Answer

• Identify exactly which ring (top compression or lower scraper) is immediately below any heat‑dam groove in the piston. • Confirm whether there is a visible drilled oil passage leading from the connecting rod up into the piston crown or gallery, indicating oil cooling. • Verify if the piston pin is shown with retainers allowing it to float, or with a tight fit to the rod eye suggesting it does not freely rotate in the bushing.