1.Technician A says that the pistons should come out the top of the block.
Technician B says to drive on the edge of the piston skirt with a punch to remove the pistons. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
- The crankshaft has been removed for inspection. Technician A says the area around the fillet is a common location for stress cracks. Technician B says a crack near the number 1 piston
connecting-rod journal may indicate a faulty vibration damper. Who is correct?
A. A only
B. B only
C. Both A and B
D. Neither A nor B
The Correct Answer and Explanation is :
1. Who is correct regarding piston removal?
Answer: D. Neither A nor B
Explanation:
- Technician A’s statement that “the pistons should come out the top of the block” is generally true in terms of typical engine assembly and disassembly, but it overlooks important steps like removing other engine components (such as the cylinder head and connecting rods) before piston removal. The pistons typically need to be removed in a methodical way, which involves taking apart components that connect them to the crankshaft.
- Technician B’s suggestion to “drive on the edge of the piston skirt with a punch” is incorrect and may damage the piston. The proper method for removing pistons involves using a piston removal tool or gently pressing them out with the appropriate equipment, not striking them with a punch. Using a punch can cause the piston skirt to crack, bend, or become damaged.
Therefore, both statements overlook critical steps or suggest inappropriate actions for piston removal.
2. Who is correct regarding crankshaft inspection?
Answer: C. Both A and B
Explanation:
- Technician A’s statement that “the area around the fillet is a common location for stress cracks” is correct. The fillet refers to the smooth curve that connects the crankshaft journal to the crankshaft’s counterweights or web. This area experiences high stress during engine operation, making it a common site for cracks, especially under high loads or fatigue.
- Technician B’s statement that “a crack near the number 1 piston connecting-rod journal may indicate a faulty vibration damper” is also correct. The vibration damper helps to reduce harmonic vibrations in the crankshaft, and if it is faulty or not functioning properly, it can result in excessive vibration that stresses the crankshaft. This can lead to cracks, particularly near the area where the connecting rod attaches.
Both statements are accurate within the context of crankshaft inspection.