AERA AERA Engine Measurement & Machining Tolerances

Question 1

What instrument is most commonly used to measure cylinder bore diameter to verify it is within AERA tolerance specifications?

Accepted Answer

Bore gauge (cylinder dial bore gauge)

Answer

Feeler gauge

Answer

Outside micrometer

Answer

Vernier caliper

Question 2

According to AERA guidelines, what term describes the maximum allowable variation in a crankshaft's main journal diameter along its length?

Accepted Answer

Taper

Answer

Runout

Answer

Ovality

Answer

End play

Question 3

When measuring crankshaft journal out-of-round (ovality), the measurement is taken at how many positions around the journal?

Accepted Answer

At least two positions 90° apart

Answer

At least four positions 45° apart

Answer

One position only

Answer

Three positions 60° apart

Question 4

Which type of micrometer is specifically designed to measure the inside diameter of a camshaft bearing bore?

Accepted Answer

Inside micrometer (tubular)

Answer

Telescoping gauge used with an outside micrometer

Answer

Depth micrometer

Answer

Thread micrometer

Question 5

AERA recommends measuring cylinder bore diameter at a minimum of how many depths to check for taper?

Accepted Answer

At least two depths — near the top and near the bottom of ring travel

Answer

One depth at mid-stroke only

Answer

Three depths including below ring travel

Answer

Four depths at equal intervals

Question 6

What is the purpose of checking crankshaft main bearing journal runout with a dial indicator and V-blocks?

Accepted Answer

To detect crankshaft straightness (bend)

Answer

To measure journal surface finish

Answer

To verify oil hole alignment

Answer

To check end play clearance