What are the two functions of the oil control ring?

• A. Distributes oil on the cylinder wall; wipes excess oil from the cylinder wall
• B. Seals the combustion chamber
• C. Guides piston
• D. Supports connecting rod

Answer: (A)

The oil control ring’s job is to manage lubrication between the piston and the cylinder wall. It does two things: first, it distributes oil evenly along the wall to keep the piston skirt and cylinder well-lubricated; second, it wipes or scrapes excess oil off the wall and returns it to the crankcase. This balance prevents too much oil from entering the combustion chamber, which would burn and raise oil consumption. The seal of the combustion chamber is the job of the compression rings above, and the oil control ring does not guide the piston or support the connecting rod.