Heavy Duty Balanced Opposed Compressors - Ariel Corporation

Section 4 Part Replacement For Models: JGH:E:K:T
2. Detach connecting rods and move them to their full outer position (see “Connecting Rods” on
page 4-28). Do not damage the crosshead guide surfaces.
3. Remove main (journal) bearing caps capscrews. Pull caps straight up to prevent damage to the
dowel fit. If cap is tight, use a bearing cap puller (see Fig. 4-37).
4. If needed, attach clean nylon straps around the crankshaft and lift it slightly to lessen weight on
the bearings and allow easier bearing shell disassembly.
5. Remove shells from main bearing caps. Remove main journal bearing shells from under the
crankshaft one at a time. To remove, rotate shell under the crankshaft, tab side out first, by pushing
or tapping with a non-metallic tool on the opposite split face side. Once completely loose, use
Ariel optional tool (part number B-3340 or fabricated from a print supplied by Ariel) to push out
shell a little. Do not damage crankshaft bearing surfaces. Replace with new bearing shell, prior to
rotating out the next main bearing shell, see steps below).
6. Clean and dry main bearing cap to bearing surfaces.
7. Check new bearing shells for damage, scratches, burrs, and loose material at the tab. DO NOT
RUB BEARING SURFACE WITH FINGERNAIL. Installation requires perfectly clean bearing
shells. New bearing shells are stamped with ink pictographs of a frame or connecting rod, for
main and connecting rod bearings respectively. Do not mix them up. Install bearing shells in
caps, and frame journals, properly located in the tab notch, (rotate in the untabbed end first),
keeping the backs of the shells dry and clean.
NOTE: Main bearings and connecting rod bearings are not interchangeable. Do not put
main bearings in connecting rod bearing locations. Do not mix part numbers on an individual
main or connecting rod. Both bearing half shells must have the same part number.
8. Replace bearing cap #1 thrust plates if crankshaft thrust clearance is not within tolerance.
9. Oil crankshaft bearing surfaces with the same clean lubricating oil used in the frame.
10. Install bearing caps containing new bearing top halves with capscrews lightly snugged in their
proper locations. Install thrust plates on #1 bearing cap. Starting at the thrust end, use the torque
procedure and Table A-3 in Appendix A to tighten the bearing cap bolts to the correct torque.
Bearing caps have position match-marks corresponding with the spacer bar and spacer bar
bosses on the frame.
11. Verify proper alignment of bearing cap dowels with the holes in the crankcase base. A set screw
on top of each dowel prevents it from backing out.
12. Check crankshaft journal bearing jack (at each bearing) and crankshaft thrust clearances to values
in Table B-1 in Appendix B (see Fig. 4-40). Record readings on a copy of the form in Appendix
D.
13. Install new connecting rod bearings and reattach connecting rods (see “Connecting Rod Installation”
on page 4-30). Tighten fasteners to torque values in Table A-3 in Appendix A. Check connecting
rod bearing jack and thrust clearances (see “Connecting Rod Bearing Removal and
Installation” on page 4-28). Record readings on a copy of the form in Appendix D.
14. If readings are not within tolerance after installing new bearings, contact your packager or Ariel
before proceeding.
15. Install spacer bars so the match mark is up and next to the spacer bar boss with the same mark.
Tighten all spacer-bar capscrews to value in Table A-3 in Appendix A.
16. Account for all tools, equipment, supplies, and parts to ensure none are left inside the crankcase.
Lubricate both sides of cover gaskets with anti-sieze lubricant or multi-purpose grease to ease
future removal. Reinstall gaskets and top cover(s). Tighten cover bolts hand wrench tight.
17. Replace coupling spacer to packager's recommendations or remove lockout.
18. After replacing bearings, thoroughly pre-lube compressor to ensure bearing lubrication and to
help remove foreign materials from the lube system.
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