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VILTER MANUFACTURING CORPORATION
VILTER MultiCylinder Compressor
400 Series VMC 2/01
SERVICE - 12 - Replaces all Previous Issues
A straight edge is positioned across the
sheave and flywheel to use as a reference to
measure the deflection of the belts.
The second method measures the amount of
stretch as the belts are tightened to deter-
mine the tension of the belts. The banded
belts are installed on the drive and rotated to
get all the slack on the bottom side. The
belts are then tightened to remove the slack
from the belts. Measure the outside circum-
ference to the nearest ¼” (6.35 mm). Multi-
ply this reading by ¾% (0.0075) to 1%
(0.01). Add this to the circumference read-
ing. Elongate the belt to the new length.
EXAMPLE: 80” x 1% = 0.8” + 80” = 80.8”
B. Direct Drive Compressors
1. Coupling Removal
Remove the guard. Remove the bolts that
extend through the coupling and remove the
center member. Remove the bolts that hold
the shim packs to coupling, and make note
of location of the washers. Using one or two
of these bolts through the shim pack will
keep the shims in alignment.
To remove the coupling from the crankshaft,
remove the screw (and washer, if present).
Try to lightly tap the coupling off the shaft, or
apply heat to coupling. A puller can be con-
structed out of a flat steel bar with holes that
match two holes in the coupling in a straight
line past the center of the crankshaft. Make
a hole in the center of the bar for a
5
/
8
”
(15.88 mm) bolt, thread the hole or weld a
5
/
8
” (15.88 mm) nut inline with the hole. Bolt
this bar loosely to holes in coupling. Place a
solid washer or disc (a little smaller than end
of the shaft) between the bar and in front of
the tapped hole in the crankshaft. Using a
5
/
8
” (15.88 mm) bolt, apply force to center
crankshaft and a pulling force on the cou-
pling.
2. Coupling Replacement
Inspect the compressor coupling bore and
crankshaft to make sure they are clean and
free of burrs. Apply anti-seize to shaft and
coupling bore. Place the key on the shaft
and slip on the coupling. Install the bolt (and
washer, if required), and tighten.
Reassemble shim pack and center member
in correct orientation. Tighten bolts and note
distance between hubs per coupling manu-
facturer’s bulletin. This bulletin is located in
the Installation Section.
Recheck alignment, if necessary.
V. CAPACITY CONTROL
A. Old Style (Mushroom Type)
1. Lift Pins, Ring and Springs Removal
The valve lifting mechanism consists of the
lift pins, lift ring and lift springs all assembled
to the cylinder liner. To remove these parts
from the cylinder liner, place the liner on a
flat surface in an upright position. Rotate the
lift ring slightly until the four semi-circular
notches line up with the lift pins, and slide
the ring down off the liner. Lift the pins out
of the top of the liner.
In order to put the unloading mechanism
onto the cylinder liner, set the lift ring on a
flat surface with the guides for the lift springs
facing up. Next place the cylinder liner in-
side the lift ring. Drop the four lift pins into
their holes in the liner with the notched ends
of the pins facing down and the flat side fac-
ing out. Lift the rings so the semicircular
notches slide over the pins. Then, rotate the
lift ring so the springs fit into their holes in
the cylinder liner.