AERA AERA Materials, Coatings & Surface Finishing

Question 1

What is the primary purpose of applying a thermal barrier coating to piston crowns in high-performance engine rebuilds per AERA guidelines?

Accepted Answer

To reduce heat transfer into the piston, lowering piston temperature and improving combustion efficiency

Answer

To increase piston weight for better inertia

Answer

To improve ring seal by roughening the crown

Answer

To prevent carbon buildup on the ring lands

Question 2

Which cylinder bore finishing process does AERA recommend to produce the correct cross-hatch angle for optimal ring seating?

Accepted Answer

Plateau honing with a proper cross-hatch pattern (typically 45–60°)

Answer

Boring only with no honing

Answer

Sand blasting the bore surface

Answer

Polishing to a mirror finish

Question 3

What is the purpose of applying a dry-film lubricant (moly) coating to piston skirts during engine rebuilding?

Accepted Answer

To reduce friction between the piston skirt and cylinder wall, especially during cold start break-in

Answer

To increase piston weight

Answer

To seal micro-cracks in the piston

Answer

To improve heat rejection from the skirt

Question 4

According to AERA guidelines, what type of surface treatment can be applied to crankshaft journals to restore hardness after grinding beyond OEM specifications?

Accepted Answer

Nitriding or chrome plating per AERA-approved processes

Answer

Shot peening only

Answer

Thermal spray (metallizing)

Answer

Case hardening by carburizing

Question 5

What does the term 'valley' refer to in the context of AERA cylinder bore surface finish specifications?

Accepted Answer

The low areas of the cross-hatch hone pattern that retain lubricating oil

Answer

The area between cylinder bores on the block

Answer

The groove cut by a boring bar

Answer

The space under the piston at BDC

Question 6

When rebuilding an aluminum block engine, what precaution does AERA specify regarding the use of steel sleeve inserts in cylinder bores?

Accepted Answer

Sleeves must be properly sized and press-fit or siamesed per spec to prevent movement and ensure correct heat transfer

Answer

Steel sleeves should never be used in aluminum blocks

Answer

Sleeves only require adhesive bonding

Answer

Sleeve material must always match the block alloy