Exam 12: Pistons, Rings, and Connecting Rods

All of the below are coatings used to reduce friction on pistons, EXCEPT _____.

Technician A says the oil rings account for 60% of total drag on the cylinder wall. Technician B says the compression rings account for 40% of total drag on the cylinder wall. Who is right?

Technician A says a wrist pin is also known as a piston pin. Technician B says a piston pin is chrome-plated, high grade carbon steel. Who is correct?

Technician A says that the full skirt piston used on long stroke engines is called a "slipper" skirt. Technician B says that a piston skirt that is cut away on its sides to clear the crankshaft counterweights is called a "trunk" skirt. Who is right?

What tool is used to check piston ring end gap clearance?

Technician A says reverse twist rings do better controlling blowby. Technician B says standard torsional twist rings do better controlling oil. Who is correct?

What is the most common method of retaining the piston pin?

A full skirt piston used on longer stroke engines is known as a(n) ____ piston.

Which type of cylinder arrangement sometimes uses offset connecting rods?

Name four common piston head shapes.

Technician A says powder forged rods are not cut; they are fractured (broken). Technician B says some rods have a spit hole to lubricate the cylinder walls at lower rpms. Who is right?

Why is there a hole or slot in the oil ring groove?

What is the name of the piston pin retaining method where the piston pin has a bushing in the connecting rod and lock rings at the ends of the piston bore?

What is the name of a piston that has a full skirt all the way around its bottom?

Does a 0.030" oversized piston weigh the same as the original standard piston?

Where is the largest diameter of the piston found?

Technician A says that all piston pins are offset from the centerline of the piston. Technician B says that most piston pins are pressed-fit in the connecting rod. Who is right?

Technician A says that conventional piston rings wear the bore more than low-tension rings. Technician B says low-tension rings must have less cylinder bore taper than conventional rings. Who is right?

How much can the cylinder bore be out of round when using moly or chrome piston rings?

Piston rings are made from all these materials, EXCEPT _____.