AERA Engine Rebuilding Techniques & Procedures 5

Question 1

When resurfacing a cylinder head, what additional check must be performed on an OHC engine before reassembly?

Accepted Answer

Verify camshaft bearing bore alignment after material removal

Answer

Removing material from an OHC head deck changes the cam-to-head geometry and can misalign camshaft bearing bores, requiring verification of bore alignment.

Question 2

What is 'porting' in the context of cylinder head reconditioning?

Accepted Answer

Enlarging and reshaping intake and exhaust ports to improve airflow

Answer

Porting involves carefully enlarging, reshaping, and smoothing intake and exhaust ports to reduce flow restrictions and increase engine breathing efficiency.

Question 3

Which measurement confirms that a cylinder block's main bearing bore is properly aligned from front to rear?

Accepted Answer

Line bore alignment measured with a precision bar or laser alignment tool

Answer

A precision alignment bar or laser tool checks whether all main bearing bores share a common centerline, confirming proper alignment before bearing installation.

Question 4

What is the effect of installing a piston with its orientation reversed (front to rear) in a non-symmetrical piston design?

Accepted Answer

Offset pin bore and valve pockets will be misaligned, causing piston damage

Answer

Non-symmetrical pistons have offset wrist pin bores and directional valve reliefs; reversing orientation misaligns these features, potentially causing contact with valves or abnormal wear.

Question 5

After a valve job, what measurement ensures that valves are not sitting too deep in the head (excessive valve sink)?

Accepted Answer

Installed valve stem height relative to a datum on the head

Answer

Measuring installed valve stem height from a reference datum on the head reveals excessive sinking of the valve into its seat, which reduces compression and may cause coil bind.

(AERA) Automotive Engine Rebuilders Association Certification Practice Test

(AERA) Automotive Engine Rebuilders Association Certification Practice Test

AERA Engine Rebuilding Techniques & Procedures 5