f. Determine the end play of the piston pin
The double.. keyway on the gerotor assembly
assembly (11) using a dial indicator. Remove or add
(15) must be a free fit over the pin (12). If this is
shims (8, 9, and 10) as required to obtain a piston pin
not so, turn the gerotor assembly over so that
assembly end play of not more than 0.001 inch.
Shimming must allow for free rotation of the piston pin
the face that was facing forward now faces
assembly while restricting the end play to a minimum.
backward and try for a free fit.
identification marks on the inner and outer
g. Disassemble the rings (6 and 7), shims (8, 9,
gerotor assembly must be facing in the same
and 10) used to obtain the proper end play and piston pin
assembly (11) from the first stage piston (3).
h. Using two small blocks of wood to compress the
e. Insert the crankshaft keystone assembly into the
rings, position the first stage piston (3) into the crankcase
crankcase (14, fig. 16) after aligning the holes in the
(14, fig. 16), the mark "F" on the piston facing the fan
gerotor assembly (15, fig. 15), with the holes in the plate
end, so that the piston pin hole in the piston is alined with
(14), and secure the plate to the crankcase using the
the piston pin port in the crankcase and the piston pin
three screws (19), washers (20) and washers (21).
orifice in the upper keystone (8, fig. 15). Insert the piston
Using the 5/32-inch socket wrench and a torque wrench,
pin assembly (11, fig. 14) into the first stage piston
torque the three screws between 2 and 3 pound-feet.
through the piston pin port of the crankcase (14, fig. 16)
f. Position the preformed packing (4) into the
and follow with the previously selected shims (8, 9, and
groove on the adapter (3).
g. Position the oil seal (6) onto the crankshaft (11)
i. Assemble the ring (6) into the groove in the
together with wave washer (5) and adapter (3). Secure
piston (3) using ring pliers.
the adapter to the crankcase (14, fig. 16) using the four
screws (1, fig. 15) and four washers (2). Apply a torque
to the four screws (1) of between 5 to 7 pound-feet.
j. Position the preformed packing (5) on the plug
h. Screw the connector (22) into the adapter (3)
(4) and screw the plug into the piston pin port of the
crankcase (14), fig. 16) end tighten securely.
i. Position the preformed packing (16), oil seal (17)
onto the front end of the crankshaft (11) and secure in
44. First Stage Valve Assembly
place with ring (18).
a. Determine the thickness of shim (4, fig. 13)
43. First Stage Piston Assembly
required to give a proper first stage head clearance
a. Rotate the crankshaft (11, fig. 15), using a piece
between 0.013 to 0.017 inches as described in b through
of suitable size hexagonal bar stock until the piston pin
i below; refer to figure 17.
hole, in the upper keystone (8) is in line with the piston
b. Position the first stage piston (3, fig. 14) to top
pin port of the first stage cylinder of the crankcase (14,.
dead center by rotating the crankshaft (11, fig. 15)"using
a suitable size hexagonal bar stock.
b. Assemble the two piston rings (1, fig. 14) in the
c. Position the spacer (3, fig. 13) and gasket (1)
grooves of the first stage piston (3), 180 apart.
into the first stage cylinder bore.
c. Assemble the ring (2) into the groove in the
piston pin orifice on the first stage piston (3).
from the flat surface of the first stage cylinder of the
d. Preassemble the piston pin assembly (11) to the
piston (3) for the proper selection of required piston pin
Record this valve as the "A" value.
shims (8, 9, and 10) as described in e through g below.;
e. Measure the distance from the flat surface of the
e. Position the piston pin assembly (11) into the
first stage cylinder to the top of the gasket (1, fig. 13).
piston pin orifice opposite the orifice with the truarc ring
Record this distance as the "B" value.
(2). Follow with the shims (8, 9, and 10), ring (7) and