FOR MODELS: JGW, JGR AND JGJ SECTION 5 - MAINTENANCE
1/01 PAGE 5 - 3
AVOID PERSONAL INJURY. THE WEIGHT OF EACH CROSSHEAD IS
LISTED IN THE BALANCE SHEET THAT COMES IN THE MANUAL WITH
EACH COMPRESSOR.)
5. Turn the crankshaft until the throw is at its highest point. Remove the top two
connecting rod bolts and the rod bearing cap. The bottom two bolts remain in
the cap while the cap is being removed.
6. Half of the bearing shell will come out with the cap. The other half can be
removed by sliding it out.
7. Turn the crankshaft until the rod can be taken out through the top opening of the
crankcase.
8. After the removal of the connecting rods, be sure to protect the crank pins from
being nicked or scratched.
NOTE: IF ALL CONNECTING RODS ARE TO BE REMOVED, IT MAY BE MORE EXPE-
DIENT TO REMOVE THE CRANKSHAFT PRIOR TO REMOVING THE RODS.
Crank Pin Bearing & Connecting Rod Bushing Removal
& Installation
Crank Pin Bearing
This is a tri-metal (steel, bronze, and babbitt with a tin flash) precision split bearing. A visual
inspection should be sufficient to determine if the bearing is serviceable. Any appreciable
wear of the babbitt would expose the bronze underneath. Such exposure indicates the need
for bearing replacement.
There are notches in the rod and rod cap for the bearing tabs in order to position and main-
tain the position of the bearing halves.
NOTE: CRANK PIN BEARINGS AND MAIN BEARINGS ARE NO LONGER FUNCTION-
ALLY INTERCHANGEABLE. CRANK PIN (CONNECTING ROD) BEARINGS
HAVE A NARROWER GROOVE. DO NOT PUT A CRANK PIN BEARING IN A
MAIN BEARING LOCATION.
Connecting Rod Bushing
Check crosshead pin to bushing clearance (see Table 1-3 on page 1-9 for recommended
clearance.) Wear on the pin can be determined by a visual inspection. Replace the pin if
necessary.
If a replacement bushing is needed, the existing bushing should be filed or hack-sawed to
within 1/32 inches (1 mm) of its thickness. It can then be easily drifted out.
A press would be helpful to install the new bushing. Do not use a hammer to force the bush-
ing into place as this will distort the bushing's bore. Lay the connecting rod on the press sur-
face so that the chamfered edge of the rod bushing hole is on top. Be sure to locate the
bushing oil hole at the connecting rod oil passage before pressing it in. The bushing has an
annular groove around its outer surface in line with the oil hole; therefore, if the bushing
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