AERA Engine Rebuilding Techniques & Procedures 4

Question 1

What is the purpose of a pilot bearing or bushing in the crankshaft flywheel end?

Accepted Answer

Support the transmission input shaft nose

Answer

The pilot bearing or bushing supports and centers the transmission or transaxle input shaft nose inside the crankshaft end.

Question 2

When Plastigage is used to check bearing clearance and shows a very wide, flat strip after cap removal, this indicates:

Accepted Answer

Clearance is excessive (too much oil clearance)

Answer

Plastigage flattens more (wider strip) when clearance is greater; a very wide strip indicates excessive oil clearance beyond specification.

Question 3

What does 'zero-deck' or 'decking to zero' mean in engine building?

Accepted Answer

Machining the block so piston crown is exactly flush with the deck at TDC

Answer

Zero-decking means machining the block surface so the piston tops are flush with (or at a specified distance from) the deck surface at TDC, maximizing compression ratio consistency.

Question 4

Which type of valve seat insert material is required in engines designed to run on unleaded fuel without hardened OEM seats?

Accepted Answer

Hardened steel or sintered iron inserts

Answer

Engines originally designed for leaded fuel need hardened steel or sintered iron seat inserts when converted to unleaded operation to prevent valve seat recession.

Question 5

What is the correct sequence for tightening main bearing cap bolts?

Accepted Answer

Start at center and work outward alternately

Answer

Main caps should be tightened starting from the center and alternating outward to distribute clamping load evenly and minimize bore distortion.

(AERA) Automotive Engine Rebuilders Association Certification Practice Test

(AERA) Automotive Engine Rebuilders Association Certification Practice Test

AERA Engine Rebuilding Techniques & Procedures 4