Rottler H85A, Operation And Maintenance Manual

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Section 5 Operating Instructions H85A Manual
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5-1
Honing In General
The H85A is capable of honing a cylinder very accurately with very little or no work from the operator.
The goal of the operator should be to create or choose a block program for the engine being honed. And
select the proper hone head, stone holders, and stone set that will allow the machine to hone the cylinder
to size with the correct finish.
While the H85A is running, the screen will show a representation of the hone head traveling up and down
in the cylinder. Along the sides will be a line that represents the cylinder wall. While the machine is honing
those lines will approximate the shape of the cylinder. If a section of the cylinder is tight then the lines
will move toward the hone head. When the tight area exceeds a predetermined amount a red mark will
appear in the area and the machine will dwell or short stroke in that area to remove the tight spot.
The H85A uses a two-step process when a cylinder is honed. When the cycle is started the machine will
run a high pressure roughing load that will allow for quick stock removal. When the cylinder is near finish
size the machine will automatically switch to a finish mode that lowers the pressure to allow for truing of
bore geometry and final sizing.
Large Amount of Material Removal
When you have large amounts of material to remove from a cylinder (.005 (.127mm) and up) the following
steps should be used to maintain size control.
For stock removal of .010 (.254mm) or more it is best to use a two step process. Start with 80 grit stones,
(.004” (.1016mm) removal per minute) use the Rough Hone process and bring all cylinders to within
.005”(.0127mm) of the final size. Switch to stones that will leave you the desired RA value and remove
the final amount of material using the Finish Hone process.
When there is less that .010” to remove start with 270 grit stones and bring cylinders to within .002”
(.0508mm) of final size using the Rough Hone process. Switch to stones that will leave you the desired
RA value and remove the final amount of material using the Finish Hone process. You can also use
the 270 grit stones and bring the cylinder to final size. Then install finishing stones and activate the
PLATEAU operation to bring the cylinder to your desired RA value.
Common Surface Finishes
Today’s modern engines are demanding smoother and more precise surface finishes. There are two
commonly used plateau surface finishes in automotive engine cylinder bore finishing today. They are
both described below. The single step, non-plateau finish is no longer recommended for engine cylinder
bores. The processes described below are commonly used in the engine building industry. If the engine
or ring manufacturer recommends a particular finish the engine manufacturers specifications or ring
manufactures recommendation should be followed.
Non-Plateau
The typical Ra finishes used for a Non-Plateau finish should be in the 16-24µin (.41-61µm) range. A 16-24
µin (.41-61 µm) Ra finish leaves adequate peaks to be knocked off during the engine break in period yet
is not so rough as to cause oil burning problems before the cylinder walls have been plateaued by the
rings. During initial start up of the engine the rings will create the plateau by knocking off the peaks of a
non-plateau finish. Most modern ring manufacturers do not recommend using this type of finish.