Exam 11: Crankshaft, Bearings, and Engine Balancing

How is dynamic imbalance corrected?

Metal is being ground from the surface of a crankshaft. Technician A says that 0.010" of metal is removed from the surface of a 0.010" crankshaft. Technician B says that 0.015" of metal is removed from the surface of a 0.030" crankshaft. Who is right?

Name three types of scales used in engine balancing.

Technician A says that spread is when the bearing insert extends above the parting surface. Technician B says that crush is what keeps the bearing from spinning in the bearing bore. Who is right?

Which crankshaft is stronger, cast or forged?

Technician A says that stretched connecting rods often need resizing when the bearing clearance at the bearing parting line becomes excessive. Technician B says that normal connecting bearing wear is on the cap end. Who is right?

Technician A says a typical V8 can be balanced in about 30 minutes. Technician B says in-line engines do not use bob weights. Who is correct?

The hardness specification is usually given on the _____ "C" scale.

When a rod journal is tapered, what should be checked as a possible cause?

Technician A says that bearing clearance can be reduced by as much as 40% with aluminum bearings. Technician B says excessive crush will allow a bearing to move back and forth in the bore. Who is correct?

Thrust bearings are being discussed. Technician A says the thrust bearing surface facing the front of the engine shows the most wear. Technician B says the most common cause of thrust bearing failure is too little clearance. Who is correct?

An engine has a burned thrust main bearing. Technician A says that this can be caused by a driver who "rides" the clutch. Technician B says that this can be caused by insufficient clutch pedal-free travel. Who is right?

What are the names of two types of hardening?

What part of the crankshaft can be rolled with a hydraulic roller to increase crankshaft strength?

What is the name of the rounded area at the edge of each bearing journal?

Technician A says that cast crankshafts have larger counterweights than forged crankshafts. Technician B says that forged crankshafts are usually externally balanced with weights on the damper and torque converter. Who is right?

At the factory, what part does the reciprocating weight of the pistons and rods play?

Technician A says that many four cylinder engines do not use a damper. Technician B says that a loose or damaged damper can break the crankshaft. Who is right?

What are engines called that are balanced with part of the counterweight on the flywheel or damper?

How much thicker than standard would a 0.020" undersized bearing insert be?