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To: dynoman
Nope, Cross hatch is visible even after 100k miles in modern engines. The cross hatch is what holds the oil in the cylinder walls.

If you are holing oil in the cylinder walls on compression stroke, your rings are failing (particularly your oil wiper rings) and you are burning oil. The only places the hone pattern is visible in the cylinder after an engine has completely broken in and the rings have seated will be at the very top ridge of the cylinder above where the compression ring travels, and at the bottom below where the oil rings travel on the areas where the piston skirt doesn't touch.

86 posted on 01/20/2022 7:46:54 AM PST by eastexsteve
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To: eastexsteve

That is completely wrong, especially with modern engines. I’ve seen many with cross hatch clearly visible all the way down the cylinder at well over 100k miles.

Hot Rod magazine has dynoed many junk yard LS engines with many miles where all they did was open up the ring gaps for boost and nitrous, put the engine back together, and more than double the HP. Cross hatch was still visible all the way down the cylinder.

“The surface finish must also meet the piston ring manufacturer’s specifications and have the proper crosshatch so the cylinder walls will retain oil and provide adequate lubrication for the rings.”

“Large, sharp peaks won’t last long once the engine is started because the tops of the peaks will be gradually sheared off by the rings as the rings break in. As the tallest peaks are knocked off, the “mountains” become flattened creating a “plateau” effect. This increases the bearing area for the rings and makes it easier for the rings to glide over the surface on a film of oil that is retained in the valleys.

According to one ring manufacturer we interviewed, once the rings have seated, wear virtually ceases because the rings are now supported by a thin film of oil and do not make physical contact with the cylinder wall. The ideal cylinder bore surface, therefore, should essentially duplicate this condition. By using the right honing procedure, you can create a surface finish that allows the rings to seat quickly with minimal wear and which will retain the proper amount of oil so the rings receive proper lubrication.”
https://www.enginebuildermag.com/2000/09/cylinder-bore-surface-finishes/

“The honing process employs a honing stone of a certain grit applied with precise pressure and speed, to create the desired cross-hatch pattern. The pattern on the cylinder-wall allows the rings to seal after a short break-in period while retaining enough oil to lubricate the piston and ring package properly.

Accomplishing the proper hone is more difficult than it might appear. When racers first started experimenting with cylinder bore finishes, their early efforts were aimed at creating a near-polished surface. This turned out to be less than desirable.

Later experiments revealed that a more optimal surface finish has a few microscopic peaks combined with deeper valleys. This offers the opportunity to store sufficient oil in the valleys to lubricate the rings while still providing a smooth enough surface to seal the rings to the bore.

This approach created what was first called a plateau finish back in the 1980s. The idea was to create the surface through a process first using rough stones to create the deeper valleys, followed by progressively-finer stones, combined with reduced load on the stones to flatten the rough peaks of the surface while retaining sufficient valley depth to lubricate the rings.”
https://www.enginelabs.com/engine-tech/enginelabs-blueprint-series-the-art-and-science-of-cylinder-honing/

I use a Sunnen plateu honing method. I built a Dodge 360 for that at almost 50k miles uses less than 1 QT/10k miles. I use Amsoil and change the oil one per year. I know I’d see crosshatch all the way down the cylinder if I took that engine apart right now.


88 posted on 01/20/2022 8:09:46 AM PST by dynoman (Objectivity is the essence of intelligence. - Marilyn vos Savant)
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