Heavy Duty Balanced Opposed Compressors - Ariel Corporation

FOR MODELS: JGZ AND JGU SECTION 5 - MAINTENANCE
CAUTION: DO NOT PLACE ANY PART OF YOUR BODY INSIDE THE CRANKCASE
WITHOUT OBSERVING THE CAUTION ON PAGE 5-1.
28. Complete remaining information on the copy of “BEARING LOG FORM/CONDI-
TIONS AFTER REPLACING BEARINGS” on Page 5-68” and fax copy to Ariel
Technical Services.
Crankshaft - Installation
1. Be sure that the correct new main bearing half shells are in place in the frame saddles,
installed absolutely clean and dry. Lubricate the frame bearing half shell bearing-surfaces
with new clean lubricating oil, same type as is used in the frame. See “Main Bearings
- Removal/Installation w/Crankshaft Removed” on Page 5-23.
2. Move the connecting rods to their full outer position. If the piston-rod-assemblies are still
attached to the crossheads, the cylinder heads or VVCP’s may have to be removed and
wiper packing gland may have to be unbolted so the crankshaft will clear the connecting
rods. While the crankshaft is being lowered very slowly into the crankcase (suspended
by a crane with clean nylon slings), one or two persons should grasp the top of the crankshaft
and slowly maneuver the drive and auxiliary ends straight down into the crankcase,
wearing clean gloves as during removal. DO NOT PLACE HANDS UNDER THE
CRANKSHAFT. Both drive end and auxiliary end journals should touch the bottom bearing
shells at the same time.
3. Clean and dry the bearing-caps and install new dry bearing half shells with their tabs
properly positioned in the slots. With the crankshaft resting on the bottom bearing shells,
lubricate upper crankshaft main bearing surfaces with new clean lubricating oil, same
type as is used in the frame, and reinstall the bearing-caps. Lubricate the cap screw
threads and seating surfaces with a thin coating of “Never-Seez”, Regular Grade and
reinstall in the bearing-caps, lightly snugged. Be sure the dowels in the bearing caps are
aligned with the holes in the crankcase base. Then, starting at the thrust end, tighten the
cap screws in an alternating (criss-cross) pattern in 25% increments to the recommended
torque, and then tighten the cap screws in an alternating (criss-cross) pattern to
the recommended turn value, see values given in Table 1-11 on Page 1-18. A separately
purchased hydraulic connecting rod/main bearing-caps cap screw torquing tool (see Figure
7-12 on Page 7-7), is recommended to achieve the final turn degrees. The hydraulic
tool is provided with its own turn indicators. This tool reacts against the opposite diagonal
cap screw. Be sure that the hydraulic tool is configured for tightening the main bearingcaps
cap screws. Set the turn indicator to the reference mark on the tool, so that the
recessed area will indicate the additional turn degrees. Bearing caps are match-marked
to correspond with the spacer bar and spacer bar bosses on the frame.
4. Reattach the connecting rods (See “Connecting Rod - Installation” on Page 5-6). reinstall
wiper packing glands, and cylinder heads or VVCP’s. Tighten fasteners to values in
Table 1-11 on Page 1-18.
5. If crosshead-balance nuts were loosened, or the crankshaft, connecting rods, cylinder
heads or VVCP’s replaced, set piston end clearance, check crosshead clearances and
check rod runout.
6. Reinstall the RTD’s/thermocouples in the main bearing caps.
7. Install new end cover gaskets. Before installing the gaskets, apply a thin coating of antiseize
lubricant to both sides or to the metal seating surfaces. This will help to hold the
gasket in place during assembly and aid in ease of future removal. Reinstall the drive
end cover, tighten fasteners hand wrench tight, and trim the excess from the new gas-
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