10
direction, to the right.
4. Carefully install gear end plate over rotor shafts. NOTE: The drive rotor should always be on the left side. Make sure the end
plate feet are facing in the proper direction so the assembled unit will have the same drive shaft location as before.
5. Mechanical Seal Series - Some earlier models used an O-ring [314] under the mating portion of the mechanical seal. This has
been discontinued and O-rings should not be used with newly purchased seals. Check lapped surface of seal mating ring to be
sure it is perfectly clean. Use soft tissue and cleaning agent if necessary. Place a few drops of lubricating oil on its surface and
install on shaft with lapped surface coming to rest on top of carbon. Gently press with fingers to insure compression is taking
place and ring is not hung up for any reason.
Slinger Seal Series - Slide seal slinger [238] over shaft. Also install spacer [129] if two piece.
6. Lubricate shafts and press the double row ball bearings [9] onto rotor shafts and into end plate bores. CAUTION: These
bearings have been flush ground at the factory. The inner race will have a black dot etched on the surface. This dot must be up
and visible when bearings are installed. Secure with bearing retainers [14], and socket head screws [30].
7. Check clearance between the face of the end plate and rotor lobes. See Clearances table on page 16 for correct gear end
clearances. If clearances are not within specifications, recheck parts to find cause of improper clearances before proceeding.
INSTALLATION OF TIMING GEARS:
8. Install spacer [17] (.260” {6.60 mm} thickness) on one shaft, and spacer [18] (.200” {5.08 mm} thickness) and oil slinger [20]
on the other shaft. NOTE: Oil slinger and its spacer should always be mounted on lower rotor for horizontal flow units. It can
be mounted on either shaft for vertical flow units. Install timing shim in same location as found in disassembly. This does not
necessarily insure the unit will be in proper time. Adjustments can be made later in the assembly process.
9. Insert gear keys [24] in their proper location and flush with top of shaft. Use the two keyways facing to the right. A tight fit is
required. Coat shafts and keys with lubricant. Install drive gear (right hand helix) on drive rotor (left side). To install driven gear,
align reference marks as shown in Fig. 6B. Install driven gear carefully to avoid damaging any teeth when engaging opposite
gear. Secure with spacers [57], washers [25], and flat head Allen screws [29]. NOTE: All timing gears must be used in sets,
as they are matched and serially numbered.
10. Remove assembly from press and stand on work table with gears down. Place blocks under end plate to prevent assembly
from falling over. Drive gear should remain on left side.
HOUSING AND FREE END ASSEMBLY:
11. Place a small bead of sealer around the periphery of the end plate, encircling each bolt hole. Install rotor housing [3] and
secure with 4 screws evenly spaced.
12. Check clearance between end of lobes and housing using a flat bar and feeler gauges or a depth micrometer. Refer to
Clearances table on page 16 for free end clearances.
13. Place a small bead of sealer around the periphery of the housing, encircling each bolt hole. Install free end plate and secure
with 4 screws.
14. Mechanical Seals - Install mating rings same as gear end, No. 5. 92/93 - Install seal slinger same as gear end.
15. Install bearing spacers [123] on each shaft. Lubricate shafts and install roller bearings [10]. CAUTION: Inner race of bearing
has a flange on one side only. This flange must face outward. See Figure 10.
16. Install oil retainer rings [14] with button head screws [30]. Only two required for each ring.
ADJUSTING ROTOR INTERLOBE CLEARANCE:
17. Install spacer [67] on each shaft. Install oil slinger [21] on lower rotor, (either shaft on vertical flow units) spacer [57] on
opposite shaft, washers [25], and screws [29]. Lay assembly down with drive on left for timing.
18. Using feeler gauges take interlobe readings and record on each side of housing as indicated in Figure 8. By removing or
adding shim behind the helical gear, it rotates as it is moved in or out and the driven rotor turns with it, thus changing the
clearance between rotor lobes. Changing the shim thickness
.006” (.15 mm) will change the rotor lobe clearance .003”
(.08 mm) or one-half the amount.
EXAMPLE: Referring to Figure 8, check the clearance a
AA (right hand reading) and BB (left hand reading). If AA
reading is .009” (.23 mm) and BB reading .003” (.08 mm)
by removing .006” (.15 mm) shims, the readings will change
one-half the amount removed or .003” (.08 mm) AA should
then read .006” (.15 mm) and BB should read .006” (.15
mm). The final reading should be within .002” (.05 mm)
of each other. To determine the amount of shim to add or
remove, subtract the small figure from the larger. If the right
side reading is higher than the left side, remove shim. If the right side reading is lower, add shim.
19. Install drive shaft [45] and secure with Allen screws [66]. Check drive shaft runout behind keyway. Do not exceed .002” (.05
Figure 7 - Keyways
DRIVE Keywayed
Shaft
Facing
Up
Keyways
Facing
Same
Direction
