Classic cylinder honing works to establish surface finish as well as dimensional truing. Surface finish is critical to not only allow oil retention, but to break up the hydrodynamic oil film boundary that can keep ring faces from making proper cylinder wall contact. In other words, the microscopic ?scratches? give the oil a place to go, much like tire tread gives rain water a place to go. The oil retained in the ?scratches? is then released in a controlled fashion to maintain a ?thin film? lubrication boundary, ideally a single molecule thick.
This thin film boundary allows the high points on the ring faces and cylinder surfaces to ?wear? down and form a metal to metal fit capable of sealing high pressure hot combustion gasses. If this oil film gets thick enough to let the ring faces ?hydroplane?, those surfaces won?t wear in (break in), hot gases can escape passed the ring faces, over heating them, AND those faces wont have intimate enough cylinder wall contact to adequately give up their heat to the cylinder wall? result: collapse?
In order for this ring face to cylinder wall metal to metal fit to seal high pressure combustion gasses, this fit MUST be very close. Ideally, closer than the width of a nitrogen molecule. Cylinder honing helps make the cylinder both round and straight. The classic 45 degree cross hatch not only establishes useful surface finish oil retention channels, but also assures the hone has exactly the same axial and radial motion. This, assures the hone has a chance to simultaneously correct taper and ?out of round?.
It also helps keep stone wear even.
Out of round cylinders leave gaps that rings must wear to fill. Tapered cylinders work the rings in and out, accelerating ring land wear and possibly fatiguing the rings.
Most of cylinder wear will be due to the top ring and causes the wear ridge. Wearing this ridge rounds the top edge of the ring to match. If you put a new ring against a previously worn ridge, it won?t have a rounded edge to match and will cause accelerated wear.
If you can measure a ridge, cut it out. Make sure the cylinders are reasonably round and straight, get the surface finish to specs and you?ll have no problems with them. Be sure to check ring grooves for taper.
Nothing can beat a GOOD bore job, but you always run a risk that it could get fouled up. These used cylinders were running and are proven quantities.
Careful with honing. It can leave grit embedded into the cylinder wall surface and cause wear that won?t be obvious for 50,000 miles? Since solvents are virtually the same weight as the honing oil, they can?t get under and lift grit the way old fashioned soap and water can. We pressure wash our honed cylinders, blow dry and IMMEDIATELY oil them to prevent rust. Be careful with oiled cylinders, or parts in general, as oil will collect dust from the air? wash, oil and assemble?
