AERA Engine Rebuilding Techniques & Procedures 2 — Questions and Answers
Question 1: When using a torque-to-yield (TTY) head bolt, what is the correct procedure?
- Reuse if visually undamaged
- Replace after each use and never reuse (Correct answer)
- Retorque to original spec after cooling
- Reuse if stretch is under 0.002 inches
Correct answer: Replace after each use and never reuse
TTY bolts plastically deform during installation and must be replaced each time to ensure proper clamping force.
Question 2: What is the primary purpose of line boring a cylinder block after main bearing cap installation?
- Increase crankshaft journal diameter
- Restore main bearing bore alignment and roundness (Correct answer)
- Remove excess bearing crush
- Enlarge the oil passages
Correct answer: Restore main bearing bore alignment and roundness
Line boring restores the main bearing bores to their correct size, shape, and alignment relative to each other.
Question 3: During piston ring installation, which ring is installed first?
- Top compression ring
- Second compression ring
- Oil control expander ring (Correct answer)
- Oil control rail
Correct answer: Oil control expander ring
The oil control expander ring is installed first in the bottom ring groove, followed by the oil rails, then the compression rings from bottom to top.
Question 4: What condition is indicated when a cylinder bore shows a pronounced taper that is largest at the top of the bore?
- Thermal expansion damage
- Normal wear from combustion pressure and ring travel (Correct answer)
- Block warpage
- Improper honing angle
Correct answer: Normal wear from combustion pressure and ring travel
Top-of-bore taper is normal wear because combustion pressure forces rings hardest against the cylinder wall at TDC where lubrication is minimal.
Question 5: What is the correct way to check crankshaft end play?
- Dial indicator measuring axial movement with crank pried fore and aft (Correct answer)
- Feeler gauge between crankshaft cheek and main cap
- Micrometer on the thrust journal
- Plastigage on the thrust bearing
Correct answer: Dial indicator measuring axial movement with crank pried fore and aft
A dial indicator mounted to measure axial movement while prying the crankshaft fore and aft gives an accurate end play reading.
Question 6: When measuring connecting rod big-end bore diameter, where should measurements be taken?
- Only at the parting line
- 90 degrees from the parting line
- At two locations 90 degrees apart to check for out-of-round (Correct answer)
- At the rod bolt holes
Correct answer: At two locations 90 degrees apart to check for out-of-round
Measuring at two locations 90 degrees apart reveals any out-of-round condition in the big-end bore.
Question 7: What is the function of valve stem seals during engine operation?
- Prevent coolant from entering the combustion chamber
- Control oil consumption by metering oil onto the valve stem (Correct answer)
- Seal combustion gases from entering the valve guide
- Maintain valve spring pressure
Correct answer: Control oil consumption by metering oil onto the valve stem
Valve stem seals meter a controlled, minimal amount of oil onto the valve stem for lubrication while preventing excessive oil from being drawn into the combustion chamber.
AERA Engine Rebuilding Techniques & Procedures 2
When using a torque-to-yield (TTY) head bolt, what is the correct procedure?