F
OR
M
ODELS
: JGI, JGM, JGN, JGP
AND
JGQ
PAGE 5-1
S
ECTION
5 - M
AINTENANCE
General Introduction
The major components of the frame assembly are the frame (or crankcase) with integral
crosshead guides, crankshaft and bearings, connecting rods, chain drive system and cross-
heads.
A cast-in oil gallery runs the length of the crankcase. Drilled oil passages feed lubricating oil
to the running gear.
The removable top cover on horizontally opposed models, (and connecting rod and chain
access covers on the JGI), and crosshead guide side covers provide generous access for
inspecting and removing internal components. The top cover is made of aluminum for easy
handling.
Absolute cleanliness, including the use of lint-free wiping cloths, is a necessity during any
maintenance on the compressor. When access covers have been removed, keep the frame
covered to protect the interior from dust except when actually working on it. Any components
that have been removed should be protected from falling objects that might mar or chip run-
ning surfaces.
Whenever the machine is dismantled, gaskets at non-pressure positions are to be carefully
inspected before reuse. Damaged gaskets must be replaced. Gaskets at pressure locations
should be replaced. Before installing a gasket, apply an 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 easy of removal.
If replacing any major reciprocating component, that is; a connecting rod assembly, piston,
piston and rod assembly, crosshead-balance nuts or crosshead, weigh component parts and
compare to the Compressor Balancing Record sheet that comes in the parts manual with
each compressor. If there are weight changes, recalculate opposing throw reciprocating