In engine remanufacturing, the surface finish of the cylinder bore directly determines oil consumption, ring seal, compression, and engine longevity. The distinction between standard honing and plateau honing—and the specialized tools each requires—is one of the most critical concepts for engine builders and remanufacturers to understand.

What Is Standard Honing?

Standard honing is the conventional process of using rigid honing stones (diamond or CBN abrasive) to establish the cylinder's geometry—correcting out-of-roundness, removing taper, and achieving the precise bore diameter. This process leaves a surface characterized by sharp, abrasive "peaks" and valleys in a normal distribution pattern, meaning there are roughly as many peaks as valleys in the roughness profile .

While standard honing achieves the required dimensional accuracy, the surface it leaves is functionally incomplete. The sharp peaks created by the stones will wear rapidly during engine break-in, generating metal particles that contaminate the oil and accelerate ring wear . This is why plateau honing was developed as the essential final step.

What Is Plateau Honing?

Plateau honing is an advanced finishing process that builds upon standard honing to create an optimized surface. A plateau surface may be defined as a honed cylinder surface that, when examined under a microscope, has had its peaks flattened to create "flat" spots or plateaus .

The process works by first using a coarse abrasive to create deep valleys (a high Rvk value), followed by a very fine abrasive to flatten the peaks (a low Rpk value) without removing the valleys . The result is a surface that:

• Reduces ring wear during break-in by eliminating sharp peaks

• Improves contact area for piston rings, enabling better sealing

• Minimizes loose material that becomes oil contaminants 

• Retains oil in deep valleys for proper cylinder lubrication

This surface structure resembles a cylinder that has already undergone normal break-in—essentially providing the benefits of hundreds of miles of operation from the first start-up.

Measuring the Difference: Surface Parameters

To understand the difference between standard and plateau honing, engine builders rely on specific surface roughness parameters:

A conventional Ra measurement alone is insufficient to characterize a plateau-honed surface. The Rk family of parameters (Rpk, Rk, Rvk, Mr1, and Mr2) as defined in ISO 13565-2 are the industry standards for evaluating cylinder bore surface quality .

The Role of Abrasive Honing Brushes

While rigid honing stones establish geometry, abrasive honing brushes are the tools that create the plateau finish. These flexible, self-centering tools feature nylon filaments impregnated with abrasive grit (typically 180-400 grit silicon carbide or aluminum oxide) .

How Abrasive Honing Brushes Work

When the brush rotates inside the cylinder bore (typically at 350-700 RPM) while moving in and out at 60-120 strokes per minute, the flexible filaments conform to the bore surface. They gently remove the sharp peaks left by rigid stones while preserving the deep oil-retaining valleys .

The brush's self-centering design ensures even contact across the entire bore surface without altering the cylinder geometry established by the stones . This is critical because any change in bore diameter or roundness would compromise the precision work done earlier in the process.

Honing Brush Operating Guidelines

Three-Stage vs. Two-Stage Honing Processes

Traditionally, achieving a plateau surface required a three-stage honing process:

1. Rough honing: Coarse stones establish geometry and base surface

2. Finish honing: Medium stones refine surface texture

3. Plateau honing: Abrasive brush creates final plateau finish 

However, modern research has demonstrated that an optimized two-stage process can achieve the desired plateau surface with significant time savings. By carefully controlling parameters such as honing pressure, roughing time, and finishing grit selection, the plateau brush step can be integrated into a streamlined process .

This advancement is particularly valuable in production engine remanufacturing, where the honing station is often the bottleneck in the cylinder block machining line. Reducing the process from three stages to two saves both machining time and tool change time .

Application in Engine Remanufacturing

For engine rebuild shops, the choice between standard and plateau honing directly impacts rebuild quality. Modern ring manufacturers specify plateau-finished surfaces for optimal ring seating and sealing. A plateau finish is particularly important for:

• High-performance and racing engines: Reduced friction and faster break-in

• Diesel engines: Improved oil retention and ring sealing under high loads 

• Turbocharged and blown applications: Enhanced durability under extreme conditions 

As one industry expert noted, standard honing leaves tiny burrs that are "magically" gone after run time, but those burrs become metal particles that contaminate the oil before being filtered out. Plateau honing skims off most of those burrs before they can cause damage .

Conclusion

The difference between standard honing and plateau honing is the difference between a functional cylinder and an optimal one. While standard honing creates geometry, plateau honing creates longevity—reducing oil consumption, accelerating ring seating, and extending engine life.

Abrasive honing brushes are the specialized tools that make plateau honing possible. Their flexible, self-centering design enables controlled removal of surface peaks without altering critical bore geometry, delivering the plateau finish that modern engine designs require for maximum performance and reliability.

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