Rottler HP 7A - Instructions for Honing Alusil and Lokasil Cylinders; When Honing Silitec Cylinders

Section 5 Operating Instructions HP7A Manual
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Instructions for Honing Alusil and Lokasil Cylinders
Cylinders should be bored to within .002 with a PCD insert. This is very important to prevent fracturing of
silicon particles below the nish surface of bore. If PCD isn’t used the exposure of the silicon will result in
a defective sliding surface for piston and rings.
*NOTE: When using the diamond stones they should be trued in to diameter of cylinder by using
them in cast iron cylinder the same diameter of aluminum cylinder being honed. This includes the
KS nish diamonds also.
Cylinders should then be honed on HP7A using Rottler 400 grit diamond stones (no substitutes only use
400 grit) to size with tolerance of +.0002 -.0000. Machine parameters should be set as follows: RPM 200
to 225, Honing loads should be set at 20% to 25% for roughing and 15% nish load.
Next install the KS nishing diamonds and run one cycle in the plateau mode. The plateau mode
parameters for the HP7A hone are normally 20% load and 7 strokes per cycle. You will need to change
these parameters (see operating instructions) to 10 strokes per cycle and a honing load of 15%. Cylinders
should already be to size from previous step. You are not trying to remove much material with this
operation. The need for this operation is to lower the surface nish for the next step.
*NOTE: Chamfer or break the edge of the exposing stones prior to using them in bore. This will
help prevent chipping on stone edges.
The last step in the process is to expose the silicon particles by eroding the surrounding metal away
from the silicon particles. This can be accomplished with different methods. The rst method (easiest
and cleanest) is to use the exposing stones part# 514-918N. These stones will need to be installed in
machine and run for two plateau cycles. The plateau cycles should be same as prior step (10 strokes and
15% honing load). The bores should be ushed with coolant after the rst plateau cycle and then second
cycle run. It is extremely important that during this last stage that operator not force exposing stones into
cylinders. Operator should start stones slightly away from cylinder wall and let machine feed stones into
cylinder wall at the 15% honing load specied. These stones are extremely soft and any forcing of stones
into cylinder wall will shorten stone life.
The second method to exposing the silicon particles is to use Rottler part# 514-9-21E. These are a felt
wiper that is used with Rottler part# 514-9-21F which is a silicon compound paste. When using this
method the coolant will need to be shutoff. Take a small paint brush and apply paste to felt wipers and the
entire cylinder. Install hone head in bore, hone for approximately 45 to 60 seconds per cylinder. Machine
settings for this operation should be RPM 160 to 170, strokes per minute of 60, shut-off automatic stone
feed up. Start machine and feed stones up manually until load reaches 15%. Let machine run for 45 to 60
seconds per cylinder. Reapply silicon compound to each cylinder. There is no need to over stroke cylinder
during this process so shorten stroke length accordingly.
For honing the Lokasil and Alusil cylinders the preferred method is the use of exposing stones; however
the other method will work.
When Honing Silitec Cylinders
When honing Silitec cylinders use the above method of boring and honing cylinders. When removing
metal away from silicon particles the second method of silicon paste and felt wipers must be used for
Silitec cylinders only.