Heavy Duty Balanced Opposed Compressors - Ariel Corporation

FOR MODELS: JGZ AND JGU SECTION 5 - MAINTENANCE
Main Bearings - Removal/Installation w/Crankshaft Removed
NOTE: MAIN BEARINGS AND CONNECTING ROD BEARINGS ARE NOT FUNCTION-
ALLY INTERCHANGEABLE. MAIN BEARINGS HAVE A WIDER GROOVE AND
LARGER OIL HOLE. DO NOT PUT A MAIN BEARING IN A CONNECTING ROD
BEARING LOCATION. DO NOT MIX BEARING SHELL PART NUMBERS ON AN
INDIVIDUAL MAIN OR CONNECTING ROD. BOTH HALF SHELLS MUST HAVE
THE SAME ARIEL PART NUMBER. IT IS ALSO RECOMMENDED THAT ALL
MAIN BEARINGS IN A COMPRESSOR HAVE THE SAME PART NUMBER.
1. Do not remove a main bearing cap to check for bearing wear, if cap is removed
it is recommended that a new bearing is installed, i.e. DO NOT REUSE BEAR-
ING SHELLS. Determine bearing wear by checking actual jack and crankshaft
thrust clearances against the clearance limits given in Table 1-4 on Page 1-13.
See “Checking Main Bearing Clearances” on Page 5-17. High copper content in
the oil analysis may be an indication of main and/or connecting rod bearing
wear, and/or chain idler, crosshead, connecting rod bushings wear (excessive
use of anti-seize lubricates can also elevate copper content in the oil analysis).
2. There are notches in the frame and bearing cap for the bearing tabs in order to
position and maintain the position of the bearing halves. Check the new bearing
shells for handling damage, scratches, burrs, and loose material at the tab. DO
NOT RUB BEARING SURFACE WITH FINGERNAIL. The bearing shells must
be absolutely clean and the outside diameter dry.
3. Remove the bearing half shell by rotating/sliding it out, tab end first. Be sure the
main bearing saddles and bearing caps are clean and dry. And crankshaft is
absolutely clean, and free from nicks and burrs. New bearings are to be rotated/
slid in (untabbed end first), and snapped into place. Locate tabs in the notches
in the bearing saddles and bearing caps.
4. See “Crankshaft - Installation” on Page 5-26.
Main Bearings - Removal/Installation w/Crankshaft In Place
NOTE: REPLACE ONE MAIN BEARING AT A TIME. REMOVE THE CAP ON THE
BEARING BEING CHANGED, CHANGE THAT BEARING AND REPLACE THE
CAP AND TIGHTEN THE BOLTING PRIOR TO STARTING THE NEXT
BEARING.
1. Operate the pre-lube pump to lubricate the bearings, prior to rotating the crankshaft.
2. Follow instructions in Caution page 5-1. Remove coupling center member or
otherwise lockout.
3. Remove the top covers, gaskets, top cover and main bearing spacer bars. Tip: If
the spacer bar cap screws are difficult to remove, use a 12 point slugging
wrench and hammer. Spacer bars are a sliding fit and should be capable of
being removed by hand, without falling out or hammering to remove. If too loose
or too tight, contact your packager or Ariel before proceeding. Remove the
RTD’s/thermocouples from the main bearing caps and place them so they will
not be damaged when replacing the bearings.
4. Remove the cap screws from main (journal) bearing cap #1. The separately purchased
hydraulic connecting rod/main bearing-caps cap screw torquing tool and
the appropriate electric or pneumatic pump (see Figure 7-12 on Page 7-7), are
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