Heavy Duty Balanced Opposed Compressors - Ariel Corporation

Section 4 Part Replacement For Models: JGH:E:K:T
Connecting Rods
A Connecting Rod assembly consists of a Rod with Bushing, a Rod Cap, Rod Cap Bolts (4), and two
half Bearing Shells. The Bearing Shells join together to form the Connecting Rod Bearing.
Connecting Rod Removal
1. Remove top cover from crankcase and side covers from crosshead guides.
2. Remove the middle frame spacer bar of the three over the desired pair of throws. TIP: If spacer
bar bolts are difficult to loosen, use a 12-point hammer wrench. Spacer bars fit snugly, but should
remove manually without hammering. They should not fall out. If fit is too loose or tight contact
your packager or Ariel before proceeding.
3. Move throw to outer dead center position.
4. Remove lock nut, bolt, end plates, and crosshead pin from crosshead. Discard old lock nut.
5. Remove crosshead as described in “Crossheads” on page 4-24.
6. Support connecting rod so it does not drop and damage the crosshead guide, then turn the
crankshaft until the throw is at its highest point. Loosen all the rod cap bolts part way. Using the
connecting rod cap removal tool (see Fig. 1-1), jack against the bolt heads to pull the rod cap free
from the dowels. Remove the top two rod cap bolts and the rod bearing cap. The bottom two
bolts remain in the cap during cap removal.
NOTE: Do not pry or chisel to separate cap from rod; it damages the connecting rod.
7. Half of the bearing shell comes out with the cap. Slide out the other half from the rod.
8. Turn crankshaft until rod can be removed through the crosshead guide side cover openings.
9. After removing connecting rod(s), protect crank pins from nicks or scratches.
NOTE: To remove all connecting rods, remove the crankshaft before rod removal. Detach
all connecting rods from the crankshaft and retract them into the crosshead guides before
crankshaft removal.
Connecting Rod Bearing Removal and Installation
The connecting rod bearing is tri-metal (steel, bronze, and babbitt with a tin flash coat) and precision
split (2-shell). Notches in the rod and rod cap enable bearing tabs to position and maintain the position
of the bearing halves. See Connecting Rod Removal above for bearing removal.
1. Do not remove connecting rod cap to check bearing wear. If cap is removed, replace the bearing.
DO NOT REUSE BEARING SHELLS.
2. To determine bearing wear, check jack and side clearances against clearance limits in Table B-3
in Appendix B. Also check clearances after new bearing installation. Use calibrated dial indicators
with 0.0005 inch (0.005 mm) increments and magnetic stands to check clearances. To check
jack clearance:
• Thread an eye bolt into the connecting rod and turn the crankshaft pin up.
• Install a magnetic stand on the crankshaft web adjacent to the connecting rod. Place a needle
dial indicator against the top of the connecting rod near the cap seam. See Fig. 4-34.
• With a large pry bar inserted into the eye bolt, pry against the frame to force the connecting rod
up until dial indicator needle stops moving. Note the reading.
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