AERA Materials, Coatings & Surface Finishing Flashcards

What is the purpose of 'plateau honing' as a two-stage process recommended by AERA for modern engine cylinder bores?

Answer: The first stage creates the cross-hatch structure; the second stage removes sharp peaks to create a plateau with oil-holding valleys

Stage one honing with a rougher stone creates the cross-hatch valleys, and stage two with a finer stone clips the sharp peaks to a smooth plateau, reducing break-in time while retaining oil reservoirs.

When AERA specifications reference Rpk, Rk, and Rvk surface parameters for cylinder bores, what does Rvk specifically measure?

Answer: The depth of the oil-retaining valleys below the core roughness plateau

Rvk (reduced valley depth) quantifies the depth of the lower valleys that hold lubricating oil, and AERA uses it to ensure adequate oil retention without excessive depth that could allow blowby.

What type of abrasive is most commonly used in AERA-recommended finishing honing stones to achieve a proper cross-hatch in cast iron bores?

Answer: Vitrified aluminum oxide or silicon carbide honing sticks

Aluminum oxide and silicon carbide vitrified honing stones self-dress as they work and produce the correct controlled cross-hatch pattern and surface texture in cast iron cylinder bores.

According to AERA guidelines, why must all machined engine parts be thoroughly cleaned with hot soapy water (not solvent alone) after honing or grinding?

Answer: Hot soapy water removes abrasive particles embedded in the metal surface; solvent only disperses but does not lift out embedded grit

Abrasive grit from honing embeds into the metal surface and solvent-wiping merely moves it around, while scrubbing with hot soapy water and a brush physically dislodges and flushes grit that would otherwise cause rapid wear.

What is the function of adding a 'top ring reversal groove' (TRRG) feature to a cylinder bore during honing per AERA performance guidelines?

Answer: The groove interrupts the wear track at the top ring reversal point, redistributing oil and reducing bore wear at the highest-stress zone

The TRRG is a shallow groove cut just above the top ring's travel limit, which breaks up the accelerated wear pattern at the reversal point and allows oil to redistribute across the wear zone.

Which AERA-recognized coating is applied to connecting rod bearing bores to improve corrosion resistance during storage and initial start-up lubrication?

Answer: A light rust preventative oil or assembly lubricant compatible with engine oil

AERA recommends applying assembly lube or rust-preventative oil to all bearing surfaces immediately after machining to protect against corrosion during storage and to provide initial lubrication on first start.